text: // Copyright (C) 2002-2012 Nikolaus Gebhardt
  // This file is part of the "Irrlicht Engine".
  // For conditions of distribution and use, see copyright notice in irrlicht.h
  
  #include "COpenGLDriver.h"
  #include "CNullDriver.h"
  #include "IContextManager.h"
  
  #ifdef _IRR_COMPILE_WITH_OPENGL_
  
  #include "os.h"
  
  #include "COpenGLCacheHandler.h"
  #include "COpenGLMaterialRenderer.h"
  #include "COpenGLShaderMaterialRenderer.h"
  #include "COpenGLSLMaterialRenderer.h"
  #include "COpenGLNormalMapRenderer.h"
  #include "COpenGLParallaxMapRenderer.h"
  
  #include "COpenGLCoreTexture.h"
  #include "COpenGLCoreRenderTarget.h"
  
  #ifdef _IRR_COMPILE_WITH_SDL_DEVICE_
  #include <SDL/SDL.h>
  #endif
  
  namespace irr
  {
  namespace video
  {
  
  // Statics variables
  const u16 COpenGLDriver::Quad2DIndices[4] = { 0, 1, 2, 3 };
  
  #if defined(_IRR_COMPILE_WITH_WINDOWS_DEVICE_) || defined(_IRR_COMPILE_WITH_X11_DEVICE_) || defined(_IRR_COMPILE_WITH_OSX_DEVICE_)
  COpenGLDriver::COpenGLDriver(const SIrrlichtCreationParameters& params, io::IFileSystem* io, IContextManager* contextManager)
  	: CNullDriver(io, params.WindowSize), COpenGLExtensionHandler(), CacheHandler(0), CurrentRenderMode(ERM_NONE), ResetRenderStates(true),
  	Transformation3DChanged(true), AntiAlias(params.AntiAlias), ColorFormat(ECF_R8G8B8), FixedPipelineState(EOFPS_ENABLE), Params(params),
  	ContextManager(contextManager),
  #if defined(_IRR_COMPILE_WITH_WINDOWS_DEVICE_)
  	DeviceType(EIDT_WIN32)
  #elif defined(_IRR_COMPILE_WITH_X11_DEVICE_)
  	DeviceType(EIDT_X11)
  #else
  	DeviceType(EIDT_OSX)
  #endif
  {
  #ifdef _DEBUG
  	setDebugName("COpenGLDriver");
  #endif
  }
  #endif
  
  #ifdef _IRR_COMPILE_WITH_SDL_DEVICE_
  COpenGLDriver::COpenGLDriver(const SIrrlichtCreationParameters& params, io::IFileSystem* io, CIrrDeviceSDL* device)
  	: CNullDriver(io, params.WindowSize), COpenGLExtensionHandler(), CacheHandler(0),
  	CurrentRenderMode(ERM_NONE), ResetRenderStates(true), Transformation3DChanged(true),
  	AntiAlias(params.AntiAlias), ColorFormat(ECF_R8G8B8), FixedPipelineState(EOFPS_ENABLE),
  	Params(params), SDLDevice(device), ContextManager(0), DeviceType(EIDT_SDL)
  {
  #ifdef _DEBUG
  	setDebugName("COpenGLDriver");
  #endif
  
  	genericDriverInit();
  }
  
  #endif
  
  bool COpenGLDriver::initDriver()
  {
  	ContextManager->generateSurface();
  	ContextManager->generateContext();
  	ExposedData = ContextManager->getContext();
  	ContextManager->activateContext(ExposedData);
  
  	genericDriverInit();
  
  #if defined(_IRR_COMPILE_WITH_WINDOWS_DEVICE_) || defined(_IRR_COMPILE_WITH_X11_DEVICE_)
  	extGlSwapInterval(Params.Vsync ? 1 : 0);
  #endif
  
  	return true;
  }
  
  //! destructor
  COpenGLDriver::~COpenGLDriver()
  {
  	RequestedLights.clear();
  
  	deleteMaterialRenders();
  
  	CacheHandler->getTextureCache().clear();
  	// I get a blue screen on my laptop, when I do not delete the
  	// textures manually before releasing the dc. Oh how I love this.
  	removeAllRenderTargets();
  	deleteAllTextures();
  	removeAllOcclusionQueries();
  	removeAllHardwareBuffers();
  
  	delete CacheHandler;
  
  	if (ContextManager)
  	{
  		ContextManager->destroyContext();
  		ContextManager->destroySurface();
  		ContextManager->terminate();
  		ContextManager->drop();
  	}
  }
  
  // -----------------------------------------------------------------------
  // METHODS
  // -----------------------------------------------------------------------
  
  bool COpenGLDriver::genericDriverInit()
  {
  	if (ContextManager)
  		ContextManager->grab();
  
  	Name=L"OpenGL ";
  	Name.append(glGetString(GL_VERSION));
  	s32 pos=Name.findNext(L' ', 7);
  	if (pos != -1)
  		Name=Name.subString(0, pos);
  	printVersion();
  
  	// print renderer information
  	const GLubyte* renderer = glGetString(GL_RENDERER);
  	const GLubyte* vendor = glGetString(GL_VENDOR);
  	if (renderer && vendor)
  	{
  		os::Printer::log(reinterpret_cast<const c8*>(renderer), reinterpret_cast<const c8*>(vendor), ELL_INFORMATION);
  		VendorName = reinterpret_cast<const c8*>(vendor);
  	}
  
  	u32 i;
  
  	// load extensions
  	initExtensions(Params.Stencilbuffer);
  
  	// reset cache handler
  	delete CacheHandler;
  	CacheHandler = new COpenGLCacheHandler(this);
  
  	if (queryFeature(EVDF_ARB_GLSL))
  	{
  		char buf[32];
  		const u32 maj = ShaderLanguageVersion/100;
  		snprintf_irr(buf, 32, "%u.%u", maj, ShaderLanguageVersion-maj*100);
  		os::Printer::log("GLSL version", buf, ELL_INFORMATION);
  	}
  	else
  		os::Printer::log("GLSL not available.", ELL_INFORMATION);
  	DriverAttributes->setAttribute("MaxTextures", (s32)Feature.TextureUnit);
  	DriverAttributes->setAttribute("MaxSupportedTextures", (s32)Feature.TextureUnit);
  	DriverAttributes->setAttribute("MaxLights", MaxLights);
  	DriverAttributes->setAttribute("MaxAnisotropy", MaxAnisotropy);
  	DriverAttributes->setAttribute("MaxUserClipPlanes", MaxUserClipPlanes);
  	DriverAttributes->setAttribute("MaxAuxBuffers", MaxAuxBuffers);
  	DriverAttributes->setAttribute("MaxMultipleRenderTargets", (s32)Feature.MultipleRenderTarget);
  	DriverAttributes->setAttribute("MaxIndices", (s32)MaxIndices);
  	DriverAttributes->setAttribute("MaxTextureSize", (s32)MaxTextureSize);
  	DriverAttributes->setAttribute("MaxGeometryVerticesOut", (s32)MaxGeometryVerticesOut);
  	DriverAttributes->setAttribute("MaxTextureLODBias", MaxTextureLODBias);
  	DriverAttributes->setAttribute("Version", Version);
  	DriverAttributes->setAttribute("ShaderLanguageVersion", ShaderLanguageVersion);
  	DriverAttributes->setAttribute("AntiAlias", AntiAlias);
  
  	glPixelStorei(GL_PACK_ALIGNMENT, 1);
  
  	UserClipPlanes.reallocate(MaxUserClipPlanes);
  	for (i=0; i<MaxUserClipPlanes; ++i)
  		UserClipPlanes.push_back(SUserClipPlane());
  
  	for (i=0; i<ETS_COUNT; ++i)
  		setTransform(static_cast<E_TRANSFORMATION_STATE>(i), core::IdentityMatrix);
  
  	setAmbientLight(SColorf(0.0f,0.0f,0.0f,0.0f));
  #ifdef GL_EXT_separate_specular_color
  	if (FeatureAvailable[IRR_EXT_separate_specular_color])
  		glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
  #endif
  	glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, 1);
  
  	Params.HandleSRGB &= ((FeatureAvailable[IRR_ARB_framebuffer_sRGB] || FeatureAvailable[IRR_EXT_framebuffer_sRGB]) &&
  		FeatureAvailable[IRR_EXT_texture_sRGB]);
  #if defined(GL_ARB_framebuffer_sRGB)
  	if (Params.HandleSRGB)
  		glEnable(GL_FRAMEBUFFER_SRGB);
  #elif defined(GL_EXT_framebuffer_sRGB)
  	if (Params.HandleSRGB)
  		glEnable(GL_FRAMEBUFFER_SRGB_EXT);
  #endif
  
  // This is a fast replacement for NORMALIZE_NORMALS
  //	if ((Version>101) || FeatureAvailable[IRR_EXT_rescale_normal])
  //		glEnable(GL_RESCALE_NORMAL_EXT);
  
  	glClearDepth(1.0);
  	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
  	glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
  	glHint(GL_POINT_SMOOTH_HINT, GL_FASTEST);
  	glFrontFace(GL_CW);
  	// adjust flat coloring scheme to DirectX version
  #if defined(GL_ARB_provoking_vertex) || defined(GL_EXT_provoking_vertex)
  	extGlProvokingVertex(GL_FIRST_VERTEX_CONVENTION_EXT);
  #endif
  
  	// Create built-in 2D quad for 2D rendering (both quads and lines).
  	Quad2DVertices[0] = S3DVertex(core::vector3df(-1.0f, 1.0f, 0.0f), core::vector3df(0.0f, 0.0f, 0.0f), SColor(255,255,255,255), core::vector2df(0.0f, 1.0f));
  	Quad2DVertices[1] = S3DVertex(core::vector3df(1.0f, 1.0f, 0.0f), core::vector3df(0.0f, 0.0f, 0.0f), SColor(255,255,255,255), core::vector2df(1.0f, 1.0f));
  	Quad2DVertices[2] = S3DVertex(core::vector3df(1.0f, -1.0f, 0.0f), core::vector3df(0.0f, 0.0f, 0.0f), SColor(255,255,255,255), core::vector2df(1.0f, 0.0f));
  	Quad2DVertices[3] = S3DVertex(core::vector3df(-1.0f, -1.0f, 0.0f), core::vector3df(0.0f, 0.0f, 0.0f), SColor(255,255,255,255), core::vector2df(0.0f, 0.0f));
  
  	// create material renderers
  	createMaterialRenderers();
  
  	// set the renderstates
  	setRenderStates3DMode();
  
  	// set fog mode
  	setFog(FogColor, FogType, FogStart, FogEnd, FogDensity, PixelFog, RangeFog);
  
  	// create matrix for flipping textures
  	TextureFlipMatrix.buildTextureTransform(0.0f, core::vector2df(0,0), core::vector2df(0,1.0f), core::vector2df(1.0f,-1.0f));
  
  	// We need to reset once more at the beginning of the first rendering.
  	// This fixes problems with intermediate changes to the material during texture load.
  	ResetRenderStates = true;
  
  	return true;
  }
  
  
  void COpenGLDriver::createMaterialRenderers()
  {
  	// create OpenGL material renderers
  
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_SOLID(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_SOLID_2_LAYER(this));
  
  	// add the same renderer for all lightmap types
  	COpenGLMaterialRenderer_LIGHTMAP* lmr = new COpenGLMaterialRenderer_LIGHTMAP(this);
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_ADD:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_M2:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_M4:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_LIGHTING:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_LIGHTING_M2:
  	addMaterialRenderer(lmr); // for EMT_LIGHTMAP_LIGHTING_M4:
  	lmr->drop();
  
  	// add remaining material renderer
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_DETAIL_MAP(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_SPHERE_MAP(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_REFLECTION_2_LAYER(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_TRANSPARENT_ADD_COLOR(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_TRANSPARENT_ALPHA_CHANNEL(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_TRANSPARENT_ALPHA_CHANNEL_REF(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_TRANSPARENT_VERTEX_ALPHA(this));
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_TRANSPARENT_REFLECTION_2_LAYER(this));
  
  	// add normal map renderers
  	s32 tmp = 0;
  	video::IMaterialRenderer* renderer = 0;
  	renderer = new COpenGLNormalMapRenderer(this, tmp, EMT_SOLID);
  	renderer->drop();
  	renderer = new COpenGLNormalMapRenderer(this, tmp, EMT_TRANSPARENT_ADD_COLOR);
  	renderer->drop();
  	renderer = new COpenGLNormalMapRenderer(this, tmp, EMT_TRANSPARENT_VERTEX_ALPHA);
  	renderer->drop();
  
  	// add parallax map renderers
  	renderer = new COpenGLParallaxMapRenderer(this, tmp, EMT_SOLID);
  	renderer->drop();
  	renderer = new COpenGLParallaxMapRenderer(this, tmp, EMT_TRANSPARENT_ADD_COLOR);
  	renderer->drop();
  	renderer = new COpenGLParallaxMapRenderer(this, tmp, EMT_TRANSPARENT_VERTEX_ALPHA);
  	renderer->drop();
  
  	// add basic 1 texture blending
  	addAndDropMaterialRenderer(new COpenGLMaterialRenderer_ONETEXTURE_BLEND(this));
  }
  
  bool COpenGLDriver::beginScene(u16 clearFlag, SColor clearColor, f32 clearDepth, u8 clearStencil, const SExposedVideoData& videoData, core::rect<s32>* sourceRect)
  {
  	CNullDriver::beginScene(clearFlag, clearColor, clearDepth, clearStencil, videoData, sourceRect);
  
  	if (ContextManager)
  		ContextManager->activateContext(videoData);
  
  #if defined(_IRR_COMPILE_WITH_SDL_DEVICE_)
  	if ( DeviceType == EIDT_SDL )
  		glFrontFace(GL_CW);
  #endif
  
  	clearBuffers(clearFlag, clearColor, clearDepth, clearStencil);
  
  	return true;
  }
  
  bool COpenGLDriver::endScene()
  {
  	CNullDriver::endScene();
  
  	glFlush();
  
  	bool status = false;
  
  	if (ContextManager)
  		status = ContextManager->swapBuffers();
  
  #ifdef _IRR_COMPILE_WITH_SDL_DEVICE_
  	if ( DeviceType == EIDT_SDL )
  	{
  		SDL_GL_SwapBuffers();
  		status = true;
  	}
  #endif
  
  	// todo: console device present
  
  	return status;
  }
  
  
  //! Returns the transformation set by setTransform
  const core::matrix4& COpenGLDriver::getTransform(E_TRANSFORMATION_STATE state) const
  {
  	return Matrices[state];
  }
  
  
  //! sets transformation
  void COpenGLDriver::setTransform(E_TRANSFORMATION_STATE state, const core::matrix4& mat)
  {
  	Matrices[state] = mat;
  	Transformation3DChanged = true;
  
  	switch (state)
  	{
  	case ETS_VIEW:
  	case ETS_WORLD:
  		{
  			// OpenGL only has a model matrix, view and world is not existent. so lets fake these two.
  			CacheHandler->setMatrixMode(GL_MODELVIEW);
  
  			// first load the viewing transformation for user clip planes
  			glLoadMatrixf((Matrices[ETS_VIEW]).pointer());
  
  			// we have to update the clip planes to the latest view matrix
  			for (u32 i=0; i<MaxUserClipPlanes; ++i)
  				if (UserClipPlanes[i].Enabled)
  					uploadClipPlane(i);
  
  			// now the real model-view matrix
  			glMultMatrixf(Matrices[ETS_WORLD].pointer());
  		}
  		break;
  	case ETS_PROJECTION:
  		{
  			CacheHandler->setMatrixMode(GL_PROJECTION);
  			glLoadMatrixf(mat.pointer());
  		}
  		break;
  	default:
  		break;
  	}
  }
  
  
  bool COpenGLDriver::updateVertexHardwareBuffer(SHWBufferLink_opengl *HWBuffer)
  {
  	if (!HWBuffer)
  		return false;
  
  	if (!FeatureAvailable[IRR_ARB_vertex_buffer_object])
  		return false;
  
  #if defined(GL_ARB_vertex_buffer_object)
  	const scene::IMeshBuffer* mb = HWBuffer->MeshBuffer;
  	const void* vertices=mb->getVertices();
  	const u32 vertexCount=mb->getVertexCount();
  	const E_VERTEX_TYPE vType=mb->getVertexType();
  	const u32 vertexSize = getVertexPitchFromType(vType);
  
  	const c8* vbuf = static_cast<const c8*>(vertices);
  	core::array<c8> buffer;
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  	{
  		//buffer vertex data, and convert colors...
  		buffer.set_used(vertexSize * vertexCount);
  		memcpy(buffer.pointer(), vertices, vertexSize * vertexCount);
  		vbuf = buffer.const_pointer();
  
  		// in order to convert the colors into opengl format (RGBA)
  		switch (vType)
  		{
  			case EVT_STANDARD:
  			{
  				S3DVertex* pb = reinterpret_cast<S3DVertex*>(buffer.pointer());
  				const S3DVertex* po = static_cast<const S3DVertex*>(vertices);
  				for (u32 i=0; i<vertexCount; i++)
  				{
  					po[i].Color.toOpenGLColor((u8*)&(pb[i].Color));
  				}
  			}
  			break;
  			case EVT_2TCOORDS:
  			{
  				S3DVertex2TCoords* pb = reinterpret_cast<S3DVertex2TCoords*>(buffer.pointer());
  				const S3DVertex2TCoords* po = static_cast<const S3DVertex2TCoords*>(vertices);
  				for (u32 i=0; i<vertexCount; i++)
  				{
  					po[i].Color.toOpenGLColor((u8*)&(pb[i].Color));
  				}
  			}
  			break;
  			case EVT_TANGENTS:
  			{
  				S3DVertexTangents* pb = reinterpret_cast<S3DVertexTangents*>(buffer.pointer());
  				const S3DVertexTangents* po = static_cast<const S3DVertexTangents*>(vertices);
  				for (u32 i=0; i<vertexCount; i++)
  				{
  					po[i].Color.toOpenGLColor((u8*)&(pb[i].Color));
  				}
  			}
  			break;
  			default:
  			{
  				return false;
  			}
  		}
  	}
  
  	//get or create buffer
  	bool newBuffer=false;
  	if (!HWBuffer->vbo_verticesID)
  	{
  		extGlGenBuffers(1, &HWBuffer->vbo_verticesID);
  		if (!HWBuffer->vbo_verticesID)
  			return false;
  		newBuffer=true;
  	}
  	else if (HWBuffer->vbo_verticesSize < vertexCount*vertexSize)
  	{
  		newBuffer=true;
  	}
  
  	extGlBindBuffer(GL_ARRAY_BUFFER, HWBuffer->vbo_verticesID);
  
  	// copy data to graphics card
  	if (!newBuffer)
  		extGlBufferSubData(GL_ARRAY_BUFFER, 0, vertexCount * vertexSize, vbuf);
  	else
  	{
  		HWBuffer->vbo_verticesSize = vertexCount*vertexSize;
  
  		if (HWBuffer->Mapped_Vertex==scene::EHM_STATIC)
  			extGlBufferData(GL_ARRAY_BUFFER, vertexCount * vertexSize, vbuf, GL_STATIC_DRAW);
  		else if (HWBuffer->Mapped_Vertex==scene::EHM_DYNAMIC)
  			extGlBufferData(GL_ARRAY_BUFFER, vertexCount * vertexSize, vbuf, GL_DYNAMIC_DRAW);
  		else //scene::EHM_STREAM
  			extGlBufferData(GL_ARRAY_BUFFER, vertexCount * vertexSize, vbuf, GL_STREAM_DRAW);
  	}
  
  	extGlBindBuffer(GL_ARRAY_BUFFER, 0);
  
  	return (!testGLError(__LINE__));
  #else
  	return false;
  #endif
  }
  
  
  bool COpenGLDriver::updateIndexHardwareBuffer(SHWBufferLink_opengl *HWBuffer)
  {
  	if (!HWBuffer)
  		return false;
  
  	if (!FeatureAvailable[IRR_ARB_vertex_buffer_object])
  		return false;
  
  #if defined(GL_ARB_vertex_buffer_object)
  	const scene::IMeshBuffer* mb = HWBuffer->MeshBuffer;
  
  	const void* indices=mb->getIndices();
  	u32 indexCount= mb->getIndexCount();
  
  	GLenum indexSize;
  	switch (mb->getIndexType())
  	{
  		case EIT_16BIT:
  		{
  			indexSize=sizeof(u16);
  			break;
  		}
  		case EIT_32BIT:
  		{
  			indexSize=sizeof(u32);
  			break;
  		}
  		default:
  		{
  			return false;
  		}
  	}
  
  
  	//get or create buffer
  	bool newBuffer=false;
  	if (!HWBuffer->vbo_indicesID)
  	{
  		extGlGenBuffers(1, &HWBuffer->vbo_indicesID);
  		if (!HWBuffer->vbo_indicesID)
  			return false;
  		newBuffer=true;
  	}
  	else if (HWBuffer->vbo_indicesSize < indexCount*indexSize)
  	{
  		newBuffer=true;
  	}
  
  	extGlBindBuffer(GL_ELEMENT_ARRAY_BUFFER, HWBuffer->vbo_indicesID);
  
  	// copy data to graphics card
  	if (!newBuffer)
  		extGlBufferSubData(GL_ELEMENT_ARRAY_BUFFER, 0, indexCount * indexSize, indices);
  	else
  	{
  		HWBuffer->vbo_indicesSize = indexCount*indexSize;
  
  		if (HWBuffer->Mapped_Index==scene::EHM_STATIC)
  			extGlBufferData(GL_ELEMENT_ARRAY_BUFFER, indexCount * indexSize, indices, GL_STATIC_DRAW);
  		else if (HWBuffer->Mapped_Index==scene::EHM_DYNAMIC)
  			extGlBufferData(GL_ELEMENT_ARRAY_BUFFER, indexCount * indexSize, indices, GL_DYNAMIC_DRAW);
  		else //scene::EHM_STREAM
  			extGlBufferData(GL_ELEMENT_ARRAY_BUFFER, indexCount * indexSize, indices, GL_STREAM_DRAW);
  	}
  
  	extGlBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
  
  	return (!testGLError(__LINE__));
  #else
  	return false;
  #endif
  }
  
  
  //! updates hardware buffer if needed
  bool COpenGLDriver::updateHardwareBuffer(SHWBufferLink *HWBuffer)
  {
  	if (!HWBuffer)
  		return false;
  
  	if (HWBuffer->Mapped_Vertex!=scene::EHM_NEVER)
  	{
  		if (HWBuffer->ChangedID_Vertex != HWBuffer->MeshBuffer->getChangedID_Vertex()
  			|| !((SHWBufferLink_opengl*)HWBuffer)->vbo_verticesID)
  		{
  
  			HWBuffer->ChangedID_Vertex = HWBuffer->MeshBuffer->getChangedID_Vertex();
  
  			if (!updateVertexHardwareBuffer((SHWBufferLink_opengl*)HWBuffer))
  				return false;
  		}
  	}
  
  	if (HWBuffer->Mapped_Index!=scene::EHM_NEVER)
  	{
  		if (HWBuffer->ChangedID_Index != HWBuffer->MeshBuffer->getChangedID_Index()
  			|| !((SHWBufferLink_opengl*)HWBuffer)->vbo_indicesID)
  		{
  
  			HWBuffer->ChangedID_Index = HWBuffer->MeshBuffer->getChangedID_Index();
  
  			if (!updateIndexHardwareBuffer((SHWBufferLink_opengl*)HWBuffer))
  				return false;
  		}
  	}
  
  	return true;
  }
  
  
  //! Create hardware buffer from meshbuffer
  COpenGLDriver::SHWBufferLink *COpenGLDriver::createHardwareBuffer(const scene::IMeshBuffer* mb)
  {
  #if defined(GL_ARB_vertex_buffer_object)
  	if (!mb || (mb->getHardwareMappingHint_Index()==scene::EHM_NEVER && mb->getHardwareMappingHint_Vertex()==scene::EHM_NEVER))
  		return 0;
  
  	SHWBufferLink_opengl *HWBuffer=new SHWBufferLink_opengl(mb);
  
  	//add to map
  	HWBufferMap.insert(HWBuffer->MeshBuffer, HWBuffer);
  
  	HWBuffer->ChangedID_Vertex=HWBuffer->MeshBuffer->getChangedID_Vertex();
  	HWBuffer->ChangedID_Index=HWBuffer->MeshBuffer->getChangedID_Index();
  	HWBuffer->Mapped_Vertex=mb->getHardwareMappingHint_Vertex();
  	HWBuffer->Mapped_Index=mb->getHardwareMappingHint_Index();
  	HWBuffer->LastUsed=0;
  	HWBuffer->vbo_verticesID=0;
  	HWBuffer->vbo_indicesID=0;
  	HWBuffer->vbo_verticesSize=0;
  	HWBuffer->vbo_indicesSize=0;
  
  	if (!updateHardwareBuffer(HWBuffer))
  	{
  		deleteHardwareBuffer(HWBuffer);
  		return 0;
  	}
  
  	return HWBuffer;
  #else
  	return 0;
  #endif
  }
  
  
  void COpenGLDriver::deleteHardwareBuffer(SHWBufferLink *_HWBuffer)
  {
  	if (!_HWBuffer)
  		return;
  
  #if defined(GL_ARB_vertex_buffer_object)
  	SHWBufferLink_opengl *HWBuffer=(SHWBufferLink_opengl*)_HWBuffer;
  	if (HWBuffer->vbo_verticesID)
  	{
  		extGlDeleteBuffers(1, &HWBuffer->vbo_verticesID);
  		HWBuffer->vbo_verticesID=0;
  	}
  	if (HWBuffer->vbo_indicesID)
  	{
  		extGlDeleteBuffers(1, &HWBuffer->vbo_indicesID);
  		HWBuffer->vbo_indicesID=0;
  	}
  #endif
  
  	CNullDriver::deleteHardwareBuffer(_HWBuffer);
  }
  
  
  //! Draw hardware buffer
  void COpenGLDriver::drawHardwareBuffer(SHWBufferLink *_HWBuffer)
  {
  	if (!_HWBuffer)
  		return;
  
  	updateHardwareBuffer(_HWBuffer); //check if update is needed
  	_HWBuffer->LastUsed=0; //reset count
  
  #if defined(GL_ARB_vertex_buffer_object)
  	SHWBufferLink_opengl *HWBuffer=(SHWBufferLink_opengl*)_HWBuffer;
  
  	const scene::IMeshBuffer* mb = HWBuffer->MeshBuffer;
  	const void *vertices=mb->getVertices();
  	const void *indexList=mb->getIndices();
  
  	if (HWBuffer->Mapped_Vertex!=scene::EHM_NEVER)
  	{
  		extGlBindBuffer(GL_ARRAY_BUFFER, HWBuffer->vbo_verticesID);
  		vertices=0;
  	}
  
  	if (HWBuffer->Mapped_Index!=scene::EHM_NEVER)
  	{
  		extGlBindBuffer(GL_ELEMENT_ARRAY_BUFFER, HWBuffer->vbo_indicesID);
  		indexList=0;
  	}
  
  	drawVertexPrimitiveList(vertices, mb->getVertexCount(), indexList, mb->getPrimitiveCount(), mb->getVertexType(), mb->getPrimitiveType(), mb->getIndexType());
  
  	if (HWBuffer->Mapped_Vertex!=scene::EHM_NEVER)
  		extGlBindBuffer(GL_ARRAY_BUFFER, 0);
  	if (HWBuffer->Mapped_Index!=scene::EHM_NEVER)
  		extGlBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
  #endif
  }
  
  
  //! Create occlusion query.
  /** Use node for identification and mesh for occlusion test. */
  void COpenGLDriver::addOcclusionQuery(scene::ISceneNode* node,
  		const scene::IMesh* mesh)
  {
  	if (!queryFeature(EVDF_OCCLUSION_QUERY))
  		return;
  
  	CNullDriver::addOcclusionQuery(node, mesh);
  	const s32 index = OcclusionQueries.linear_search(SOccQuery(node));
  	if ((index != -1) && (OcclusionQueries[index].UID == 0))
  		extGlGenQueries(1, reinterpret_cast<GLuint*>(&OcclusionQueries[index].UID));
  }
  
  
  //! Remove occlusion query.
  void COpenGLDriver::removeOcclusionQuery(scene::ISceneNode* node)
  {
  	const s32 index = OcclusionQueries.linear_search(SOccQuery(node));
  	if (index != -1)
  	{
  		if (OcclusionQueries[index].UID != 0)
  			extGlDeleteQueries(1, reinterpret_cast<GLuint*>(&OcclusionQueries[index].UID));
  		CNullDriver::removeOcclusionQuery(node);
  	}
  }
  
  
  //! Run occlusion query. Draws mesh stored in query.
  /** If the mesh shall not be rendered visible, use
  overrideMaterial to disable the color and depth buffer. */
  void COpenGLDriver::runOcclusionQuery(scene::ISceneNode* node, bool visible)
  {
  	if (!node)
  		return;
  
  	const s32 index = OcclusionQueries.linear_search(SOccQuery(node));
  	if (index != -1)
  	{
  		if (OcclusionQueries[index].UID)
  			extGlBeginQuery(
  #ifdef GL_ARB_occlusion_query
  				GL_SAMPLES_PASSED_ARB,
  #else
  				0,
  #endif
  				OcclusionQueries[index].UID);
  		CNullDriver::runOcclusionQuery(node,visible);
  		if (OcclusionQueries[index].UID)
  			extGlEndQuery(
  #ifdef GL_ARB_occlusion_query
  				GL_SAMPLES_PASSED_ARB);
  #else
  				0);
  #endif
  		testGLError(__LINE__);
  	}
  }
  
  
  //! Update occlusion query. Retrieves results from GPU.
  /** If the query shall not block, set the flag to false.
  Update might not occur in this case, though */
  void COpenGLDriver::updateOcclusionQuery(scene::ISceneNode* node, bool block)
  {
  	const s32 index = OcclusionQueries.linear_search(SOccQuery(node));
  	if (index != -1)
  	{
  		// not yet started
  		if (OcclusionQueries[index].Run==u32(~0))
  			return;
  		GLint available = block?GL_TRUE:GL_FALSE;
  		if (!block)
  			extGlGetQueryObjectiv(OcclusionQueries[index].UID,
  #ifdef GL_ARB_occlusion_query
  						GL_QUERY_RESULT_AVAILABLE_ARB,
  #elif defined(GL_NV_occlusion_query)
  						GL_PIXEL_COUNT_AVAILABLE_NV,
  #else
  						0,
  #endif
  						&available);
  		testGLError(__LINE__);
  		if (available==GL_TRUE)
  		{
  			extGlGetQueryObjectiv(OcclusionQueries[index].UID,
  #ifdef GL_ARB_occlusion_query
  						GL_QUERY_RESULT_ARB,
  #elif defined(GL_NV_occlusion_query)
  						GL_PIXEL_COUNT_NV,
  #else
  						0,
  #endif
  						&available);
  			if (queryFeature(EVDF_OCCLUSION_QUERY))
  				OcclusionQueries[index].Result = available;
  		}
  		testGLError(__LINE__);
  	}
  }
  
  
  //! Return query result.
  /** Return value is the number of visible pixels/fragments.
  The value is a safe approximation, i.e. can be larger than the
  actual value of pixels. */
  u32 COpenGLDriver::getOcclusionQueryResult(scene::ISceneNode* node) const
  {
  	const s32 index = OcclusionQueries.linear_search(SOccQuery(node));
  	if (index != -1)
  		return OcclusionQueries[index].Result;
  	else
  		return ~0;
  }
  
  
  //! Create render target.
  IRenderTarget* COpenGLDriver::addRenderTarget()
  {
  	COpenGLRenderTarget* renderTarget = new COpenGLRenderTarget(this);
  	RenderTargets.push_back(renderTarget);
  
  	return renderTarget;
  }
  
  
  // small helper function to create vertex buffer object adress offsets
  static inline u8* buffer_offset(const long offset)
  {
  	return ((u8*)0 + offset);
  }
  
  
  //! draws a vertex primitive list
  void COpenGLDriver::drawVertexPrimitiveList(const void* vertices, u32 vertexCount,
  		const void* indexList, u32 primitiveCount,
  		E_VERTEX_TYPE vType, scene::E_PRIMITIVE_TYPE pType, E_INDEX_TYPE iType)
  {
  	if (!primitiveCount || !vertexCount)
  		return;
  
  	if (!checkPrimitiveCount(primitiveCount))
  		return;
  
  	CNullDriver::drawVertexPrimitiveList(vertices, vertexCount, indexList, primitiveCount, vType, pType, iType);
  
  	if (vertices && !FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(vertices, vertexCount, vType);
  
  	// draw everything
  	setRenderStates3DMode();
  
  	if ((pType!=scene::EPT_POINTS) && (pType!=scene::EPT_POINT_SPRITES))
  		CacheHandler->setClientState(true, true, true, true);
  	else
  		CacheHandler->setClientState(true, false, true, false);
  
  //due to missing defines in OSX headers, we have to be more specific with this check
  //#if defined(GL_ARB_vertex_array_bgra) || defined(GL_EXT_vertex_array_bgra)
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (vertices)
  	{
  		if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		{
  			switch (vType)
  			{
  				case EVT_STANDARD:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].Color);
  					break;
  				case EVT_2TCOORDS:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].Color);
  					break;
  				case EVT_TANGENTS:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Color);
  					break;
  			}
  		}
  		else
  		{
  			// avoid passing broken pointer to OpenGL
  			_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  			glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  		}
  	}
  
  	switch (vType)
  	{
  		case EVT_STANDARD:
  			if (vertices)
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].Normal);
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].TCoords);
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertex), buffer_offset(12));
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), buffer_offset(28));
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex), 0);
  			}
  
  			if (Feature.TextureUnit > 0 && CacheHandler->getTextureCache()[1])
  			{
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].TCoords);
  				else
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), buffer_offset(28));
  			}
  			break;
  		case EVT_2TCOORDS:
  			if (vertices)
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].Normal);
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].TCoords);
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(12));
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex2TCoords), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(28));
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(0));
  			}
  
  
  			if (Feature.TextureUnit > 0)
  			{
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].TCoords2);
  				else
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(36));
  			}
  			break;
  		case EVT_TANGENTS:
  			if (vertices)
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Normal);
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].TCoords);
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glNormalPointer(GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(12));
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertexTangents), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(28));
  				glVertexPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(0));
  			}
  
  			if (Feature.TextureUnit > 0)
  			{
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Tangent);
  				else
  					glTexCoordPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(36));
  
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 2);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Binormal);
  				else
  					glTexCoordPointer(3, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(48));
  			}
  			break;
  	}
  
  	renderArray(indexList, primitiveCount, pType, iType);
  
  	if (Feature.TextureUnit > 0)
  	{
  		if (vType==EVT_TANGENTS)
  		{
  			CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 2);
  			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
  		}
  		if ((vType!=EVT_STANDARD) || CacheHandler->getTextureCache()[1])
  		{
  			CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
  		}
  		CacheHandler->setClientActiveTexture(GL_TEXTURE0);
  	}
  }
  
  
  void COpenGLDriver::getColorBuffer(const void* vertices, u32 vertexCount, E_VERTEX_TYPE vType)
  {
  	// convert colors to gl color format.
  	vertexCount *= 4; //reused as color component count
  	ColorBuffer.set_used(vertexCount);
  	u32 i;
  
  	switch (vType)
  	{
  		case EVT_STANDARD:
  		{
  			const S3DVertex* p = static_cast<const S3DVertex*>(vertices);
  			for (i=0; i<vertexCount; i+=4)
  			{
  				p->Color.toOpenGLColor(&ColorBuffer[i]);
  				++p;
  			}
  		}
  		break;
  		case EVT_2TCOORDS:
  		{
  			const S3DVertex2TCoords* p = static_cast<const S3DVertex2TCoords*>(vertices);
  			for (i=0; i<vertexCount; i+=4)
  			{
  				p->Color.toOpenGLColor(&ColorBuffer[i]);
  				++p;
  			}
  		}
  		break;
  		case EVT_TANGENTS:
  		{
  			const S3DVertexTangents* p = static_cast<const S3DVertexTangents*>(vertices);
  			for (i=0; i<vertexCount; i+=4)
  			{
  				p->Color.toOpenGLColor(&ColorBuffer[i]);
  				++p;
  			}
  		}
  		break;
  	}
  }
  
  
  void COpenGLDriver::renderArray(const void* indexList, u32 primitiveCount,
  		scene::E_PRIMITIVE_TYPE pType, E_INDEX_TYPE iType)
  {
  	GLenum indexSize=0;
  
  	switch (iType)
  	{
  		case EIT_16BIT:
  		{
  			indexSize=GL_UNSIGNED_SHORT;
  			break;
  		}
  		case EIT_32BIT:
  		{
  			indexSize=GL_UNSIGNED_INT;
  			break;
  		}
  	}
  
  	switch (pType)
  	{
  		case scene::EPT_POINTS:
  		case scene::EPT_POINT_SPRITES:
  		{
  #ifdef GL_ARB_point_sprite
  			if (pType==scene::EPT_POINT_SPRITES && FeatureAvailable[IRR_ARB_point_sprite])
  				glEnable(GL_POINT_SPRITE_ARB);
  #endif
  
  			// prepare size and attenuation (where supported)
  			GLfloat particleSize=Material.Thickness;
  //			if (AntiAlias)
  //				particleSize=core::clamp(particleSize, DimSmoothedPoint[0], DimSmoothedPoint[1]);
  //			else
  				particleSize=core::clamp(particleSize, DimAliasedPoint[0], DimAliasedPoint[1]);
  #if defined(GL_VERSION_1_4) || defined(GL_ARB_point_parameters) || defined(GL_EXT_point_parameters) || defined(GL_SGIS_point_parameters)
  			const float att[] = {1.0f, 1.0f, 0.0f};
  #if defined(GL_VERSION_1_4)
  			extGlPointParameterfv(GL_POINT_DISTANCE_ATTENUATION, att);
  //			extGlPointParameterf(GL_POINT_SIZE_MIN,1.f);
  			extGlPointParameterf(GL_POINT_SIZE_MAX, particleSize);
  			extGlPointParameterf(GL_POINT_FADE_THRESHOLD_SIZE, 1.0f);
  #elif defined(GL_ARB_point_parameters)
  			extGlPointParameterfv(GL_POINT_DISTANCE_ATTENUATION_ARB, att);
  //			extGlPointParameterf(GL_POINT_SIZE_MIN_ARB,1.f);
  			extGlPointParameterf(GL_POINT_SIZE_MAX_ARB, particleSize);
  			extGlPointParameterf(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 1.0f);
  #elif defined(GL_EXT_point_parameters)
  			extGlPointParameterfv(GL_DISTANCE_ATTENUATION_EXT, att);
  //			extGlPointParameterf(GL_POINT_SIZE_MIN_EXT,1.f);
  			extGlPointParameterf(GL_POINT_SIZE_MAX_EXT, particleSize);
  			extGlPointParameterf(GL_POINT_FADE_THRESHOLD_SIZE_EXT, 1.0f);
  #elif defined(GL_SGIS_point_parameters)
  			extGlPointParameterfv(GL_DISTANCE_ATTENUATION_SGIS, att);
  //			extGlPointParameterf(GL_POINT_SIZE_MIN_SGIS,1.f);
  			extGlPointParameterf(GL_POINT_SIZE_MAX_SGIS, particleSize);
  			extGlPointParameterf(GL_POINT_FADE_THRESHOLD_SIZE_SGIS, 1.0f);
  #endif
  #endif
  			glPointSize(particleSize);
  
  #ifdef GL_ARB_point_sprite
  			if (pType == scene::EPT_POINT_SPRITES && FeatureAvailable[IRR_ARB_point_sprite])
  			{
  				CacheHandler->setActiveTexture(GL_TEXTURE0_ARB);
  				glTexEnvf(GL_POINT_SPRITE_ARB, GL_COORD_REPLACE, GL_TRUE);
  			}
  #endif
  			glDrawArrays(GL_POINTS, 0, primitiveCount);
  #ifdef GL_ARB_point_sprite
  			if (pType==scene::EPT_POINT_SPRITES && FeatureAvailable[IRR_ARB_point_sprite])
  			{
  				glDisable(GL_POINT_SPRITE_ARB);
  
  				CacheHandler->setActiveTexture(GL_TEXTURE0_ARB);
  				glTexEnvf(GL_POINT_SPRITE_ARB,GL_COORD_REPLACE, GL_FALSE);
  			}
  #endif
  		}
  			break;
  		case scene::EPT_LINE_STRIP:
  			glDrawElements(GL_LINE_STRIP, primitiveCount+1, indexSize, indexList);
  			break;
  		case scene::EPT_LINE_LOOP:
  			glDrawElements(GL_LINE_LOOP, primitiveCount, indexSize, indexList);
  			break;
  		case scene::EPT_LINES:
  			glDrawElements(GL_LINES, primitiveCount*2, indexSize, indexList);
  			break;
  		case scene::EPT_TRIANGLE_STRIP:
  			glDrawElements(GL_TRIANGLE_STRIP, primitiveCount+2, indexSize, indexList);
  			break;
  		case scene::EPT_TRIANGLE_FAN:
  			glDrawElements(GL_TRIANGLE_FAN, primitiveCount+2, indexSize, indexList);
  			break;
  		case scene::EPT_TRIANGLES:
  			glDrawElements(GL_TRIANGLES, primitiveCount*3, indexSize, indexList);
  			break;
  		case scene::EPT_QUAD_STRIP:
  			glDrawElements(GL_QUAD_STRIP, primitiveCount*2+2, indexSize, indexList);
  			break;
  		case scene::EPT_QUADS:
  			glDrawElements(GL_QUADS, primitiveCount*4, indexSize, indexList);
  			break;
  		case scene::EPT_POLYGON:
  			glDrawElements(GL_POLYGON, primitiveCount, indexSize, indexList);
  			break;
  	}
  }
  
  
  //! draws a vertex primitive list in 2d
  void COpenGLDriver::draw2DVertexPrimitiveList(const void* vertices, u32 vertexCount,
  		const void* indexList, u32 primitiveCount,
  		E_VERTEX_TYPE vType, scene::E_PRIMITIVE_TYPE pType, E_INDEX_TYPE iType)
  {
  	if (!primitiveCount || !vertexCount)
  		return;
  
  	if (!checkPrimitiveCount(primitiveCount))
  		return;
  
  	CNullDriver::draw2DVertexPrimitiveList(vertices, vertexCount, indexList, primitiveCount, vType, pType, iType);
  
  	if (vertices && !FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(vertices, vertexCount, vType);
  
  	// draw everything
  	CacheHandler->getTextureCache().set(0, Material.getTexture(0));
  	if (Material.MaterialType==EMT_ONETEXTURE_BLEND)
  	{
  		E_BLEND_FACTOR srcFact;
  		E_BLEND_FACTOR dstFact;
  		E_MODULATE_FUNC modulo;
  		u32 alphaSource;
  		unpack_textureBlendFunc ( srcFact, dstFact, modulo, alphaSource, Material.MaterialTypeParam);
  		setRenderStates2DMode(alphaSource&video::EAS_VERTEX_COLOR, (Material.getTexture(0) != 0), (alphaSource&video::EAS_TEXTURE) != 0);
  	}
  	else
  		setRenderStates2DMode(Material.MaterialType==EMT_TRANSPARENT_VERTEX_ALPHA, (Material.getTexture(0) != 0), Material.MaterialType==EMT_TRANSPARENT_ALPHA_CHANNEL);
  
  	if ((pType!=scene::EPT_POINTS) && (pType!=scene::EPT_POINT_SPRITES))
  		CacheHandler->setClientState(true, false, true, true);
  	else
  		CacheHandler->setClientState(true, false, true, false);
  
  //due to missing defines in OSX headers, we have to be more specific with this check
  //#if defined(GL_ARB_vertex_array_bgra) || defined(GL_EXT_vertex_array_bgra)
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (vertices)
  	{
  		if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		{
  			switch (vType)
  			{
  				case EVT_STANDARD:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].Color);
  					break;
  				case EVT_2TCOORDS:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].Color);
  					break;
  				case EVT_TANGENTS:
  					glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Color);
  					break;
  			}
  		}
  		else
  		{
  			// avoid passing broken pointer to OpenGL
  			_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  			glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  		}
  	}
  
  	switch (vType)
  	{
  		case EVT_STANDARD:
  			if (vertices)
  			{
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].TCoords);
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), buffer_offset(28));
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), 0);
  			}
  
  			if (Feature.TextureUnit > 0 && CacheHandler->getTextureCache()[1])
  			{
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(vertices))[0].TCoords);
  				else
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), buffer_offset(28));
  			}
  			break;
  		case EVT_2TCOORDS:
  			if (vertices)
  			{
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].TCoords);
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex2TCoords), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(28));
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(0));
  			}
  
  			if (Feature.TextureUnit > 0)
  			{
  				CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  				if (vertices)
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), &(static_cast<const S3DVertex2TCoords*>(vertices))[0].TCoords2);
  				else
  					glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex2TCoords), buffer_offset(36));
  			}
  			break;
  		case EVT_TANGENTS:
  			if (vertices)
  			{
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].TCoords);
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), &(static_cast<const S3DVertexTangents*>(vertices))[0].Pos);
  			}
  			else
  			{
  				glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertexTangents), buffer_offset(24));
  				glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(28));
  				glVertexPointer(2, GL_FLOAT, sizeof(S3DVertexTangents), buffer_offset(0));
  			}
  
  			break;
  	}
  
  	renderArray(indexList, primitiveCount, pType, iType);
  
  	if (Feature.TextureUnit > 0)
  	{
  		if ((vType!=EVT_STANDARD) || CacheHandler->getTextureCache()[1])
  		{
  			CacheHandler->setClientActiveTexture(GL_TEXTURE0 + 1);
  			glDisableClientState(GL_TEXTURE_COORD_ARRAY);
  		}
  		CacheHandler->setClientActiveTexture(GL_TEXTURE0);
  	}
  }
  
  
  void COpenGLDriver::draw2DImage(const video::ITexture* texture, const core::position2d<s32>& destPos,
  	const core::rect<s32>& sourceRect, const core::rect<s32>* clipRect, SColor color,
  	bool useAlphaChannelOfTexture)
  {
  	if (!texture)
  		return;
  
  	if (!sourceRect.isValid())
  		return;
  
  	// clip these coordinates
  	core::rect<s32> targetRect(destPos, sourceRect.getSize());
  	if (clipRect)
  	{
  		targetRect.clipAgainst(*clipRect);
  		if ( targetRect.getWidth() < 0 || targetRect.getHeight() < 0 )
  			return;
  	}
  
  	const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  	targetRect.clipAgainst( core::rect<s32>(0,0, (s32)renderTargetSize.Width, (s32)renderTargetSize.Height) );
  	if ( targetRect.getWidth() < 0 || targetRect.getHeight() < 0 )
  			return;
  
  	// ok, we've clipped everything.
  	// now draw it.
  	const core::dimension2d<s32> sourceSize(targetRect.getSize());
  	const core::position2d<s32> sourcePos(sourceRect.UpperLeftCorner + (targetRect.UpperLeftCorner-destPos));
  
  	const core::dimension2d<u32>& ss = texture->getOriginalSize();
  	const f32 invW = 1.f / static_cast<f32>(ss.Width);
  	const f32 invH = 1.f / static_cast<f32>(ss.Height);
  	const core::rect<f32> tcoords(
  		sourcePos.X * invW,
  		sourcePos.Y * invH,
  		(sourcePos.X + sourceSize.Width) * invW,
  		(sourcePos.Y + sourceSize.Height) * invH);
  
  	disableTextures(1);
  	if (!CacheHandler->getTextureCache().set(0, texture))
  		return;
  	setRenderStates2DMode(color.getAlpha()<255, true, useAlphaChannelOfTexture);
  
  	Quad2DVertices[0].Color = color;
  	Quad2DVertices[1].Color = color;
  	Quad2DVertices[2].Color = color;
  	Quad2DVertices[3].Color = color;
  
  	Quad2DVertices[0].Pos = core::vector3df((f32)targetRect.UpperLeftCorner.X, (f32)targetRect.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[1].Pos = core::vector3df((f32)targetRect.LowerRightCorner.X, (f32)targetRect.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[2].Pos = core::vector3df((f32)targetRect.LowerRightCorner.X, (f32)targetRect.LowerRightCorner.Y, 0.0f);
  	Quad2DVertices[3].Pos = core::vector3df((f32)targetRect.UpperLeftCorner.X, (f32)targetRect.LowerRightCorner.Y, 0.0f);
  
  	Quad2DVertices[0].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.UpperLeftCorner.Y);
  	Quad2DVertices[1].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.UpperLeftCorner.Y);
  	Quad2DVertices[2].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.LowerRightCorner.Y);
  	Quad2DVertices[3].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.LowerRightCorner.Y);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, true);
  
  	glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].TCoords);
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize = (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra]) ? GL_BGRA : 4;
  #else
  	const GLint colorSize = 4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size() == 0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  }
  
  
  void COpenGLDriver::draw2DImage(const video::ITexture* texture, const core::rect<s32>& destRect,
  	const core::rect<s32>& sourceRect, const core::rect<s32>* clipRect,
  	const video::SColor* const colors, bool useAlphaChannelOfTexture)
  {
  	if (!texture)
  		return;
  
  	const core::dimension2d<u32>& ss = texture->getOriginalSize();
  	const f32 invW = 1.f / static_cast<f32>(ss.Width);
  	const f32 invH = 1.f / static_cast<f32>(ss.Height);
  	const core::rect<f32> tcoords(
  		sourceRect.UpperLeftCorner.X * invW,
  		sourceRect.UpperLeftCorner.Y * invH,
  		sourceRect.LowerRightCorner.X * invW,
  		sourceRect.LowerRightCorner.Y *invH);
  
  	const video::SColor temp[4] =
  	{
  		0xFFFFFFFF,
  		0xFFFFFFFF,
  		0xFFFFFFFF,
  		0xFFFFFFFF
  	};
  
  	const video::SColor* const useColor = colors ? colors : temp;
  
  	disableTextures(1);
  	if (!CacheHandler->getTextureCache().set(0, texture))
  		return;
  	setRenderStates2DMode(useColor[0].getAlpha()<255 || useColor[1].getAlpha()<255 ||
  		useColor[2].getAlpha()<255 || useColor[3].getAlpha()<255,
  		true, useAlphaChannelOfTexture);
  
  	if (clipRect)
  	{
  		if (!clipRect->isValid())
  			return;
  
  		glEnable(GL_SCISSOR_TEST);
  		const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  		glScissor(clipRect->UpperLeftCorner.X, renderTargetSize.Height - clipRect->LowerRightCorner.Y,
  			clipRect->getWidth(), clipRect->getHeight());
  	}
  
  	Quad2DVertices[0].Color = useColor[0];
  	Quad2DVertices[1].Color = useColor[3];
  	Quad2DVertices[2].Color = useColor[2];
  	Quad2DVertices[3].Color = useColor[1];
  
  	Quad2DVertices[0].Pos = core::vector3df((f32)destRect.UpperLeftCorner.X, (f32)destRect.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[1].Pos = core::vector3df((f32)destRect.LowerRightCorner.X, (f32)destRect.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[2].Pos = core::vector3df((f32)destRect.LowerRightCorner.X, (f32)destRect.LowerRightCorner.Y, 0.0f);
  	Quad2DVertices[3].Pos = core::vector3df((f32)destRect.UpperLeftCorner.X, (f32)destRect.LowerRightCorner.Y, 0.0f);
  
  	Quad2DVertices[0].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.UpperLeftCorner.Y);
  	Quad2DVertices[1].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.UpperLeftCorner.Y);
  	Quad2DVertices[2].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.LowerRightCorner.Y);
  	Quad2DVertices[3].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.LowerRightCorner.Y);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, true);
  
  	glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].TCoords);
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize = (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra]) ? GL_BGRA : 4;
  #else
  	const GLint colorSize = 4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size() == 0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  
  	if (clipRect)
  		glDisable(GL_SCISSOR_TEST);
  }
  
  
  void COpenGLDriver::draw2DImage(const video::ITexture* texture, u32 layer, bool flip)
  {
  	if (!texture || !CacheHandler->getTextureCache().set(0, texture))
  		return;
  
  	disableTextures(1);
  
  	setRenderStates2DMode(false, true, true);
  
  	CacheHandler->setMatrixMode(GL_PROJECTION);
  	glLoadIdentity();
  	CacheHandler->setMatrixMode(GL_MODELVIEW);
  	glLoadIdentity();
  
  	Transformation3DChanged = true;
  
  	CacheHandler->setClientState(true, false, false, true);
  
  	const core::vector3df positionData[4] = {
  		core::vector3df(-1.f, 1.f, 0.f),
  		core::vector3df(1.f, 1.f, 0.f),
  		core::vector3df(1.f, -1.f, 0.f),
  		core::vector3df(-1.f, -1.f, 0.f)
  	};
  
  	glVertexPointer(2, GL_FLOAT, sizeof(core::vector3df), positionData);
  
  	if (texture && texture->getType() == ETT_CUBEMAP)
  	{
  		const core::vector3df texcoordCubeData[6][4] = {
  
  			// GL_TEXTURE_CUBE_MAP_POSITIVE_X
  			{
  				core::vector3df(1.f, 1.f, 1.f),
  				core::vector3df(1.f, 1.f, -1.f),
  				core::vector3df(1.f, -1.f, -1.f),
  				core::vector3df(1.f, -1.f, 1.f)
  			},
  
  			// GL_TEXTURE_CUBE_MAP_NEGATIVE_X
  			{
  				core::vector3df(-1.f, 1.f, -1.f),
  				core::vector3df(-1.f, 1.f, 1.f),
  				core::vector3df(-1.f, -1.f, 1.f),
  				core::vector3df(-1.f, -1.f, -1.f)
  			},
  
  			// GL_TEXTURE_CUBE_MAP_POSITIVE_Y
  			{
  				core::vector3df(-1.f, 1.f, -1.f),
  				core::vector3df(1.f, 1.f, -1.f),
  				core::vector3df(1.f, 1.f, 1.f),
  				core::vector3df(-1.f, 1.f, 1.f)
  			},
  
  			// GL_TEXTURE_CUBE_MAP_NEGATIVE_Y
  			{
  				core::vector3df(-1.f, -1.f, 1.f),
  				core::vector3df(-1.f, -1.f, -1.f),
  				core::vector3df(1.f, -1.f, -1.f),
  				core::vector3df(1.f, -1.f, 1.f)
  			},
  
  			// GL_TEXTURE_CUBE_MAP_POSITIVE_Z
  			{
  				core::vector3df(-1.f, 1.f, 1.f),
  				core::vector3df(-1.f, -1.f, 1.f),
  				core::vector3df(1.f, -1.f, 1.f),
  				core::vector3df(1.f, 1.f, 1.f)
  			},
  
  			// GL_TEXTURE_CUBE_MAP_NEGATIVE_Z
  			{
  				core::vector3df(1.f, 1.f, -1.f),
  				core::vector3df(-1.f, 1.f, -1.f),
  				core::vector3df(-1.f, -1.f, -1.f),
  				core::vector3df(1.f, -1.f, -1.f)
  			}
  		};
  
  		const core::vector3df texcoordData[4] = {
  			texcoordCubeData[layer][(flip) ? 3 : 0],
  			texcoordCubeData[layer][(flip) ? 2 : 1],
  			texcoordCubeData[layer][(flip) ? 1 : 2],
  			texcoordCubeData[layer][(flip) ? 0 : 3]
  		};
  
  		glTexCoordPointer(3, GL_FLOAT, sizeof(core::vector3df), texcoordData);
  	}
  	else
  	{
  		f32 modificator = (flip) ? 1.f : 0.f;
  
  		core::vector2df texcoordData[4] = {
  			core::vector2df(0.f, 0.f + modificator),
  			core::vector2df(1.f, 0.f + modificator),
  			core::vector2df(1.f, 1.f - modificator),
  			core::vector2df(0.f, 1.f - modificator)
  		};
  
  		glTexCoordPointer(2, GL_FLOAT, sizeof(core::vector2df), texcoordData);
  	}
  
  	glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  }
  
  
  //! draws a set of 2d images, using a color and the alpha channel of the
  //! texture if desired.
  void COpenGLDriver::draw2DImageBatch(const video::ITexture* texture,
  				const core::array<core::position2d<s32> >& positions,
  				const core::array<core::rect<s32> >& sourceRects,
  				const core::rect<s32>* clipRect,
  				SColor color,
  				bool useAlphaChannelOfTexture)
  {
  	if (!texture)
  		return;
  
  	const u32 drawCount = core::min_<u32>(positions.size(), sourceRects.size());
  
  	const core::dimension2d<u32>& ss = texture->getOriginalSize();
  	const f32 invW = 1.f / static_cast<f32>(ss.Width);
  	const f32 invH = 1.f / static_cast<f32>(ss.Height);
  	const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  
  	disableTextures(1);
  	if (!CacheHandler->getTextureCache().set(0, texture))
  		return;
  	setRenderStates2DMode(color.getAlpha()<255, true, useAlphaChannelOfTexture);
  
  	Quad2DVertices[0].Color = color;
  	Quad2DVertices[1].Color = color;
  	Quad2DVertices[2].Color = color;
  	Quad2DVertices[3].Color = color;
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, true);
  
  	glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].TCoords);
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	for (u32 i=0; i<drawCount; ++i)
  	{
  		if (!sourceRects[i].isValid())
  			continue;
  
  		core::position2d<s32> targetPos(positions[i]);
  		core::position2d<s32> sourcePos(sourceRects[i].UpperLeftCorner);
  		// This needs to be signed as it may go negative.
  		core::dimension2d<s32> sourceSize(sourceRects[i].getSize());
  		if (clipRect)
  		{
  			if (targetPos.X < clipRect->UpperLeftCorner.X)
  			{
  				sourceSize.Width += targetPos.X - clipRect->UpperLeftCorner.X;
  				if (sourceSize.Width <= 0)
  					continue;
  
  				sourcePos.X -= targetPos.X - clipRect->UpperLeftCorner.X;
  				targetPos.X = clipRect->UpperLeftCorner.X;
  			}
  
  			if (targetPos.X + sourceSize.Width > clipRect->LowerRightCorner.X)
  			{
  				sourceSize.Width -= (targetPos.X + sourceSize.Width) - clipRect->LowerRightCorner.X;
  				if (sourceSize.Width <= 0)
  					continue;
  			}
  
  			if (targetPos.Y < clipRect->UpperLeftCorner.Y)
  			{
  				sourceSize.Height += targetPos.Y - clipRect->UpperLeftCorner.Y;
  				if (sourceSize.Height <= 0)
  					continue;
  
  				sourcePos.Y -= targetPos.Y - clipRect->UpperLeftCorner.Y;
  				targetPos.Y = clipRect->UpperLeftCorner.Y;
  			}
  
  			if (targetPos.Y + sourceSize.Height > clipRect->LowerRightCorner.Y)
  			{
  				sourceSize.Height -= (targetPos.Y + sourceSize.Height) - clipRect->LowerRightCorner.Y;
  				if (sourceSize.Height <= 0)
  					continue;
  			}
  		}
  
  		// clip these coordinates
  
  		if (targetPos.X<0)
  		{
  			sourceSize.Width += targetPos.X;
  			if (sourceSize.Width <= 0)
  				continue;
  
  			sourcePos.X -= targetPos.X;
  			targetPos.X = 0;
  		}
  
  		if (targetPos.X + sourceSize.Width > (s32)renderTargetSize.Width)
  		{
  			sourceSize.Width -= (targetPos.X + sourceSize.Width) - renderTargetSize.Width;
  			if (sourceSize.Width <= 0)
  				continue;
  		}
  
  		if (targetPos.Y<0)
  		{
  			sourceSize.Height += targetPos.Y;
  			if (sourceSize.Height <= 0)
  				continue;
  
  			sourcePos.Y -= targetPos.Y;
  			targetPos.Y = 0;
  		}
  
  		if (targetPos.Y + sourceSize.Height > (s32)renderTargetSize.Height)
  		{
  			sourceSize.Height -= (targetPos.Y + sourceSize.Height) - renderTargetSize.Height;
  			if (sourceSize.Height <= 0)
  				continue;
  		}
  
  		// ok, we've clipped everything.
  		// now draw it.
  
  		const core::rect<f32> tcoords(
  				sourcePos.X * invW,
  				sourcePos.Y * invH,
  				(sourcePos.X + sourceSize.Width) * invW,
  				(sourcePos.Y + sourceSize.Height) * invH);
  
  		const core::rect<s32> poss(targetPos, sourceSize);
  
  		Quad2DVertices[0].Pos = core::vector3df((f32)poss.UpperLeftCorner.X, (f32)poss.UpperLeftCorner.Y, 0.0f);
  		Quad2DVertices[1].Pos = core::vector3df((f32)poss.LowerRightCorner.X, (f32)poss.UpperLeftCorner.Y, 0.0f);
  		Quad2DVertices[2].Pos = core::vector3df((f32)poss.LowerRightCorner.X, (f32)poss.LowerRightCorner.Y, 0.0f);
  		Quad2DVertices[3].Pos = core::vector3df((f32)poss.UpperLeftCorner.X, (f32)poss.LowerRightCorner.Y, 0.0f);
  
  		Quad2DVertices[0].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.UpperLeftCorner.Y);
  		Quad2DVertices[1].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.UpperLeftCorner.Y);
  		Quad2DVertices[2].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.LowerRightCorner.Y);
  		Quad2DVertices[3].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.LowerRightCorner.Y);
  
  		glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  	}
  }
  
  
  //! draws a set of 2d images, using a color and the alpha channel of the
  //! texture if desired. The images are drawn beginning at pos and concatenated
  //! in one line. All drawings are clipped against clipRect (if != 0).
  //! The subtextures are defined by the array of sourceRects and are chosen
  //! by the indices given.
  void COpenGLDriver::draw2DImageBatch(const video::ITexture* texture,
  				const core::position2d<s32>& pos,
  				const core::array<core::rect<s32> >& sourceRects,
  				const core::array<s32>& indices,
  				s32 kerningWidth,
  				const core::rect<s32>* clipRect, SColor color,
  				bool useAlphaChannelOfTexture)
  {
  	if (!texture)
  		return;
  
  	disableTextures(1);
  	if (!CacheHandler->getTextureCache().set(0, texture))
  		return;
  	setRenderStates2DMode(color.getAlpha()<255, true, useAlphaChannelOfTexture);
  
  	if (clipRect)
  	{
  		if (!clipRect->isValid())
  			return;
  
  		glEnable(GL_SCISSOR_TEST);
  		const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  		glScissor(clipRect->UpperLeftCorner.X, renderTargetSize.Height-clipRect->LowerRightCorner.Y,
  			clipRect->getWidth(),clipRect->getHeight());
  	}
  
  	const core::dimension2d<u32>& ss = texture->getOriginalSize();
  	core::position2d<s32> targetPos(pos);
  	const f32 invW = 1.f / static_cast<f32>(ss.Width);
  	const f32 invH = 1.f / static_cast<f32>(ss.Height);
  
  	Quad2DVertices[0].Color = color;
  	Quad2DVertices[1].Color = color;
  	Quad2DVertices[2].Color = color;
  	Quad2DVertices[3].Color = color;
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, true);
  
  	glTexCoordPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].TCoords);
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	for (u32 i=0; i<indices.size(); ++i)
  	{
  		const s32 currentIndex = indices[i];
  		if (!sourceRects[currentIndex].isValid())
  			break;
  
  		const core::rect<f32> tcoords(
  				sourceRects[currentIndex].UpperLeftCorner.X * invW,
  				sourceRects[currentIndex].UpperLeftCorner.Y * invH,
  				sourceRects[currentIndex].LowerRightCorner.X * invW,
  				sourceRects[currentIndex].LowerRightCorner.Y * invH);
  
  		const core::rect<s32> poss(targetPos, sourceRects[currentIndex].getSize());
  
  		Quad2DVertices[0].Pos = core::vector3df((f32)poss.UpperLeftCorner.X, (f32)poss.UpperLeftCorner.Y, 0.0f);
  		Quad2DVertices[1].Pos = core::vector3df((f32)poss.LowerRightCorner.X, (f32)poss.UpperLeftCorner.Y, 0.0f);
  		Quad2DVertices[2].Pos = core::vector3df((f32)poss.LowerRightCorner.X, (f32)poss.LowerRightCorner.Y, 0.0f);
  		Quad2DVertices[3].Pos = core::vector3df((f32)poss.UpperLeftCorner.X, (f32)poss.LowerRightCorner.Y, 0.0f);
  
  		Quad2DVertices[0].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.UpperLeftCorner.Y);
  		Quad2DVertices[1].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.UpperLeftCorner.Y);
  		Quad2DVertices[2].TCoords = core::vector2df(tcoords.LowerRightCorner.X, tcoords.LowerRightCorner.Y);
  		Quad2DVertices[3].TCoords = core::vector2df(tcoords.UpperLeftCorner.X, tcoords.LowerRightCorner.Y);
  
  		glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  
  		targetPos.X += sourceRects[currentIndex].getWidth();
  	}
  
  	if (clipRect)
  		glDisable(GL_SCISSOR_TEST);
  }
  
  
  //! draw a 2d rectangle
  void COpenGLDriver::draw2DRectangle(SColor color, const core::rect<s32>& position,
  		const core::rect<s32>* clip)
  {
  	disableTextures();
  	setRenderStates2DMode(color.getAlpha() < 255, false, false);
  
  	core::rect<s32> pos = position;
  
  	if (clip)
  		pos.clipAgainst(*clip);
  
  	if (!pos.isValid())
  		return;
  
  	glColor4ub(color.getRed(), color.getGreen(), color.getBlue(), color.getAlpha());
  	glRectf(GLfloat(pos.UpperLeftCorner.X), GLfloat(pos.UpperLeftCorner.Y),
  		GLfloat(pos.LowerRightCorner.X), GLfloat(pos.LowerRightCorner.Y));
  }
  
  
  //! draw an 2d rectangle
  void COpenGLDriver::draw2DRectangle(const core::rect<s32>& position,
  			SColor colorLeftUp, SColor colorRightUp, SColor colorLeftDown, SColor colorRightDown,
  			const core::rect<s32>* clip)
  {
  	core::rect<s32> pos = position;
  
  	if (clip)
  		pos.clipAgainst(*clip);
  
  	if (!pos.isValid())
  		return;
  
  	disableTextures();
  
  	setRenderStates2DMode(colorLeftUp.getAlpha() < 255 ||
  		colorRightUp.getAlpha() < 255 ||
  		colorLeftDown.getAlpha() < 255 ||
  		colorRightDown.getAlpha() < 255, false, false);
  
  	Quad2DVertices[0].Color = colorLeftUp;
  	Quad2DVertices[1].Color = colorRightUp;
  	Quad2DVertices[2].Color = colorRightDown;
  	Quad2DVertices[3].Color = colorLeftDown;
  
  	Quad2DVertices[0].Pos = core::vector3df((f32)pos.UpperLeftCorner.X, (f32)pos.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[1].Pos = core::vector3df((f32)pos.LowerRightCorner.X, (f32)pos.UpperLeftCorner.Y, 0.0f);
  	Quad2DVertices[2].Pos = core::vector3df((f32)pos.LowerRightCorner.X, (f32)pos.LowerRightCorner.Y, 0.0f);
  	Quad2DVertices[3].Pos = core::vector3df((f32)pos.UpperLeftCorner.X, (f32)pos.LowerRightCorner.Y, 0.0f);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, false);
  
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  }
  
  
  //! Draws a 2d line.
  void COpenGLDriver::draw2DLine(const core::position2d<s32>& start,
  				const core::position2d<s32>& end, SColor color)
  {
  	// TODO: It's not pixel-exact. Reason is the way OpenGL handles line-drawing (search the web for "diamond exit rule").
  
  	if (start==end)
  		drawPixel(start.X, start.Y, color);
  	else
  	{
  		disableTextures();
  		setRenderStates2DMode(color.getAlpha() < 255, false, false);
  
  		Quad2DVertices[0].Color = color;
  		Quad2DVertices[1].Color = color;
  
  		Quad2DVertices[0].Pos = core::vector3df((f32)start.X, (f32)start.Y, 0.0f);
  		Quad2DVertices[1].Pos = core::vector3df((f32)end.X, (f32)end.Y, 0.0f);
  
  		if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  			getColorBuffer(Quad2DVertices, 2, EVT_STANDARD);
  
  		CacheHandler->setClientState(true, false, true, false);
  
  		glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  		const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  		const GLint colorSize=4;
  #endif
  		if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  			glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  		else
  		{
  			_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  			glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  		}
  
  		glDrawElements(GL_LINES, 2, GL_UNSIGNED_SHORT, Quad2DIndices);
  	}
  }
  
  //! Draws a pixel
  void COpenGLDriver::drawPixel(u32 x, u32 y, const SColor &color)
  {
  	const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  	if (x > (u32)renderTargetSize.Width || y > (u32)renderTargetSize.Height)
  		return;
  
  	disableTextures();
  	setRenderStates2DMode(color.getAlpha() < 255, false, false);
  
  	Quad2DVertices[0].Color = color;
  
  	Quad2DVertices[0].Pos = core::vector3df((f32)x, (f32)y, 0.0f);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 1, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, false);
  
  	glVertexPointer(2, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawArrays(GL_POINTS, 0, 1);
  }
  
  //! disables all textures beginning with the optional fromStage parameter. Otherwise all texture stages are disabled.
  //! Returns whether disabling was successful or not.
  bool COpenGLDriver::disableTextures(u32 fromStage)
  {
  	bool result=true;
  	for (u32 i=fromStage; i<Feature.TextureUnit; ++i)
  	{
  		result &= CacheHandler->getTextureCache().set(i, 0);
  	}
  	return result;
  }
  
  
  //! creates a matrix in supplied GLfloat array to pass to OpenGL
  inline void COpenGLDriver::getGLMatrix(GLfloat gl_matrix[16], const core::matrix4& m)
  {
  	memcpy(gl_matrix, m.pointer(), 16 * sizeof(f32));
  }
  
  
  //! creates a opengltexturematrix from a D3D style texture matrix
  inline void COpenGLDriver::getGLTextureMatrix(GLfloat *o, const core::matrix4& m)
  {
  	o[0] = m[0];
  	o[1] = m[1];
  	o[2] = 0.f;
  	o[3] = 0.f;
  
  	o[4] = m[4];
  	o[5] = m[5];
  	o[6] = 0.f;
  	o[7] = 0.f;
  
  	o[8] = 0.f;
  	o[9] = 0.f;
  	o[10] = 1.f;
  	o[11] = 0.f;
  
  	o[12] = m[8];
  	o[13] = m[9];
  	o[14] = 0.f;
  	o[15] = 1.f;
  }
  
  ITexture* COpenGLDriver::createDeviceDependentTexture(const io::path& name, IImage* image)
  {
  	core::array<IImage*> imageArray(1);
  	imageArray.push_back(image);
  
  	COpenGLTexture* texture = new COpenGLTexture(name, imageArray, ETT_2D, this);
  
  	return texture;
  }
  
  ITexture* COpenGLDriver::createDeviceDependentTextureCubemap(const io::path& name, const core::array<IImage*>& image)
  {
  	COpenGLTexture* texture = new COpenGLTexture(name, image, ETT_CUBEMAP, this);
  
  	return texture;
  }
  
  //! Sets a material. All 3d drawing functions draw geometry now using this material.
  void COpenGLDriver::setMaterial(const SMaterial& material)
  {
  	Material = material;
  	OverrideMaterial.apply(Material);
  
  	for (u32 i = 0; i < Feature.TextureUnit; ++i)
  	{
  		CacheHandler->getTextureCache().set(i, material.getTexture(i));
  		setTransform((E_TRANSFORMATION_STATE)(ETS_TEXTURE_0 + i), material.getTextureMatrix(i));
  	}
  }
  
  
  //! prints error if an error happened.
  bool COpenGLDriver::testGLError(int code)
  {
  #ifdef _DEBUG
  	GLenum g = glGetError();
  	switch (g)
  	{
  	case GL_NO_ERROR:
  		return false;
  	case GL_INVALID_ENUM:
  		os::Printer::log("GL_INVALID_ENUM", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_INVALID_VALUE:
  		os::Printer::log("GL_INVALID_VALUE", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_INVALID_OPERATION:
  		os::Printer::log("GL_INVALID_OPERATION", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_STACK_OVERFLOW:
  		os::Printer::log("GL_STACK_OVERFLOW", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_STACK_UNDERFLOW:
  		os::Printer::log("GL_STACK_UNDERFLOW", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_OUT_OF_MEMORY:
  		os::Printer::log("GL_OUT_OF_MEMORY", core::stringc(code).c_str(), ELL_ERROR); break;
  	case GL_TABLE_TOO_LARGE:
  		os::Printer::log("GL_TABLE_TOO_LARGE", core::stringc(code).c_str(), ELL_ERROR); break;
  #if defined(GL_EXT_framebuffer_object)
  	case GL_INVALID_FRAMEBUFFER_OPERATION_EXT:
  		os::Printer::log("GL_INVALID_FRAMEBUFFER_OPERATION", core::stringc(code).c_str(), ELL_ERROR); break;
  #endif
  	};
  //	_IRR_DEBUG_BREAK_IF(true);
  	return true;
  #else
  	return false;
  #endif
  }
  
  
  //! sets the needed renderstates
  void COpenGLDriver::setRenderStates3DMode()
  {
  	if (CurrentRenderMode != ERM_3D)
  	{
  		// Reset Texture Stages
  		CacheHandler->setBlend(false);
  		CacheHandler->setAlphaTest(false);
  		CacheHandler->setBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  		CacheHandler->setActiveTexture(GL_TEXTURE0_ARB);
  		glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  
  		// switch back the matrices
  		CacheHandler->setMatrixMode(GL_MODELVIEW);
  		glLoadMatrixf((Matrices[ETS_VIEW] * Matrices[ETS_WORLD]).pointer());
  
  		CacheHandler->setMatrixMode(GL_PROJECTION);
  		glLoadMatrixf(Matrices[ETS_PROJECTION].pointer());
  
  		ResetRenderStates = true;
  #ifdef GL_EXT_clip_volume_hint
  		if (FeatureAvailable[IRR_EXT_clip_volume_hint])
  			glHint(GL_CLIP_VOLUME_CLIPPING_HINT_EXT, GL_NICEST);
  #endif
  	}
  
  	if (ResetRenderStates || LastMaterial != Material)
  	{
  		// unset old material
  
  		if (LastMaterial.MaterialType != Material.MaterialType &&
  				static_cast<u32>(LastMaterial.MaterialType) < MaterialRenderers.size())
  			MaterialRenderers[LastMaterial.MaterialType].Renderer->OnUnsetMaterial();
  
  		// set new material.
  		if (static_cast<u32>(Material.MaterialType) < MaterialRenderers.size())
  			MaterialRenderers[Material.MaterialType].Renderer->OnSetMaterial(
  				Material, LastMaterial, ResetRenderStates, this);
  
  		LastMaterial = Material;
  		ResetRenderStates = false;
  	}
  
  	if (static_cast<u32>(Material.MaterialType) < MaterialRenderers.size())
  		MaterialRenderers[Material.MaterialType].Renderer->OnRender(this, video::EVT_STANDARD);
  
  	CurrentRenderMode = ERM_3D;
  }
  
  
  //! Get native wrap mode value
  GLint COpenGLDriver::getTextureWrapMode(const u8 clamp)
  {
  	GLint mode=GL_REPEAT;
  	switch (clamp)
  	{
  		case ETC_REPEAT:
  			mode=GL_REPEAT;
  			break;
  		case ETC_CLAMP:
  			mode=GL_CLAMP;
  			break;
  		case ETC_CLAMP_TO_EDGE:
  #ifdef GL_VERSION_1_2
  			if (Version>101)
  				mode=GL_CLAMP_TO_EDGE;
  			else
  #endif
  #ifdef GL_SGIS_texture_edge_clamp
  			if (FeatureAvailable[IRR_SGIS_texture_edge_clamp])
  				mode=GL_CLAMP_TO_EDGE_SGIS;
  			else
  #endif
  				// fallback
  				mode=GL_CLAMP;
  			break;
  		case ETC_CLAMP_TO_BORDER:
  #ifdef GL_VERSION_1_3
  			if (Version>102)
  				mode=GL_CLAMP_TO_BORDER;
  			else
  #endif
  #ifdef GL_ARB_texture_border_clamp
  			if (FeatureAvailable[IRR_ARB_texture_border_clamp])
  				mode=GL_CLAMP_TO_BORDER_ARB;
  			else
  #endif
  #ifdef GL_SGIS_texture_border_clamp
  			if (FeatureAvailable[IRR_SGIS_texture_border_clamp])
  				mode=GL_CLAMP_TO_BORDER_SGIS;
  			else
  #endif
  				// fallback
  				mode=GL_CLAMP;
  			break;
  		case ETC_MIRROR:
  #ifdef GL_VERSION_1_4
  			if (Version>103)
  				mode=GL_MIRRORED_REPEAT;
  			else
  #endif
  #ifdef GL_ARB_texture_border_clamp
  			if (FeatureAvailable[IRR_ARB_texture_mirrored_repeat])
  				mode=GL_MIRRORED_REPEAT_ARB;
  			else
  #endif
  #ifdef GL_IBM_texture_mirrored_repeat
  			if (FeatureAvailable[IRR_IBM_texture_mirrored_repeat])
  				mode=GL_MIRRORED_REPEAT_IBM;
  			else
  #endif
  				mode=GL_REPEAT;
  			break;
  		case ETC_MIRROR_CLAMP:
  #ifdef GL_EXT_texture_mirror_clamp
  			if (FeatureAvailable[IRR_EXT_texture_mirror_clamp])
  				mode=GL_MIRROR_CLAMP_EXT;
  			else
  #endif
  #if defined(GL_ATI_texture_mirror_once)
  			if (FeatureAvailable[IRR_ATI_texture_mirror_once])
  				mode=GL_MIRROR_CLAMP_ATI;
  			else
  #endif
  				mode=GL_CLAMP;
  			break;
  		case ETC_MIRROR_CLAMP_TO_EDGE:
  #ifdef GL_EXT_texture_mirror_clamp
  			if (FeatureAvailable[IRR_EXT_texture_mirror_clamp])
  				mode=GL_MIRROR_CLAMP_TO_EDGE_EXT;
  			else
  #endif
  #if defined(GL_ATI_texture_mirror_once)
  			if (FeatureAvailable[IRR_ATI_texture_mirror_once])
  				mode=GL_MIRROR_CLAMP_TO_EDGE_ATI;
  			else
  #endif
  				mode=GL_CLAMP;
  			break;
  		case ETC_MIRROR_CLAMP_TO_BORDER:
  #ifdef GL_EXT_texture_mirror_clamp
  			if (FeatureAvailable[IRR_EXT_texture_mirror_clamp])
  				mode=GL_MIRROR_CLAMP_TO_BORDER_EXT;
  			else
  #endif
  				mode=GL_CLAMP;
  			break;
  	}
  	return mode;
  }
  
  
  //! Can be called by an IMaterialRenderer to make its work easier.
  void COpenGLDriver::setBasicRenderStates(const SMaterial& material, const SMaterial& lastmaterial,
  	bool resetAllRenderStates)
  {
  	// Fixed pipeline isn't important for shader based materials
  
  	E_OPENGL_FIXED_PIPELINE_STATE tempState = FixedPipelineState;
  
  	if (resetAllRenderStates || tempState == EOFPS_ENABLE || tempState == EOFPS_DISABLE_TO_ENABLE)
  	{
  		// material colors
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.ColorMaterial != material.ColorMaterial)
  		{
  			switch (material.ColorMaterial)
  			{
  			case ECM_NONE:
  				glDisable(GL_COLOR_MATERIAL);
  				break;
  			case ECM_DIFFUSE:
  				glColorMaterial(GL_FRONT_AND_BACK, GL_DIFFUSE);
  				break;
  			case ECM_AMBIENT:
  				glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT);
  				break;
  			case ECM_EMISSIVE:
  				glColorMaterial(GL_FRONT_AND_BACK, GL_EMISSION);
  				break;
  			case ECM_SPECULAR:
  				glColorMaterial(GL_FRONT_AND_BACK, GL_SPECULAR);
  				break;
  			case ECM_DIFFUSE_AND_AMBIENT:
  				glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
  				break;
  			}
  			if (material.ColorMaterial != ECM_NONE)
  				glEnable(GL_COLOR_MATERIAL);
  		}
  
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.AmbientColor != material.AmbientColor ||
  			lastmaterial.DiffuseColor != material.DiffuseColor ||
  			lastmaterial.EmissiveColor != material.EmissiveColor ||
  			lastmaterial.ColorMaterial != material.ColorMaterial)
  		{
  			GLfloat color[4];
  
  			const f32 inv = 1.0f / 255.0f;
  
  			if ((material.ColorMaterial != video::ECM_AMBIENT) &&
  				(material.ColorMaterial != video::ECM_DIFFUSE_AND_AMBIENT))
  			{
  				color[0] = material.AmbientColor.getRed() * inv;
  				color[1] = material.AmbientColor.getGreen() * inv;
  				color[2] = material.AmbientColor.getBlue() * inv;
  				color[3] = material.AmbientColor.getAlpha() * inv;
  				glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, color);
  			}
  
  			if ((material.ColorMaterial != video::ECM_DIFFUSE) &&
  				(material.ColorMaterial != video::ECM_DIFFUSE_AND_AMBIENT))
  			{
  				color[0] = material.DiffuseColor.getRed() * inv;
  				color[1] = material.DiffuseColor.getGreen() * inv;
  				color[2] = material.DiffuseColor.getBlue() * inv;
  				color[3] = material.DiffuseColor.getAlpha() * inv;
  				glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, color);
  			}
  
  			if (material.ColorMaterial != video::ECM_EMISSIVE)
  			{
  				color[0] = material.EmissiveColor.getRed() * inv;
  				color[1] = material.EmissiveColor.getGreen() * inv;
  				color[2] = material.EmissiveColor.getBlue() * inv;
  				color[3] = material.EmissiveColor.getAlpha() * inv;
  				glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, color);
  			}
  		}
  
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.SpecularColor != material.SpecularColor ||
  			lastmaterial.Shininess != material.Shininess ||
  			lastmaterial.ColorMaterial != material.ColorMaterial)
  		{
  			GLfloat color[4]={0.f,0.f,0.f,1.f};
  			const f32 inv = 1.0f / 255.0f;
  
  			glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, material.Shininess);
  			// disable Specular colors if no shininess is set
  			if ((material.Shininess != 0.0f) &&
  				(material.ColorMaterial != video::ECM_SPECULAR))
  			{
  #ifdef GL_EXT_separate_specular_color
  				if (FeatureAvailable[IRR_EXT_separate_specular_color])
  					glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
  #endif
  				color[0] = material.SpecularColor.getRed() * inv;
  				color[1] = material.SpecularColor.getGreen() * inv;
  				color[2] = material.SpecularColor.getBlue() * inv;
  				color[3] = material.SpecularColor.getAlpha() * inv;
  			}
  #ifdef GL_EXT_separate_specular_color
  			else if (FeatureAvailable[IRR_EXT_separate_specular_color])
  				glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SINGLE_COLOR);
  #endif
  			glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, color);
  		}
  
  		// shademode
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.GouraudShading != material.GouraudShading)
  		{
  			if (material.GouraudShading)
  				glShadeModel(GL_SMOOTH);
  			else
  				glShadeModel(GL_FLAT);
  		}
  
  		// lighting
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.Lighting != material.Lighting)
  		{
  			if (material.Lighting)
  				glEnable(GL_LIGHTING);
  			else
  				glDisable(GL_LIGHTING);
  		}
  
  		// fog
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.FogEnable != material.FogEnable)
  		{
  			if (material.FogEnable)
  				glEnable(GL_FOG);
  			else
  				glDisable(GL_FOG);
  		}
  
  		// normalization
  		if (resetAllRenderStates || tempState == EOFPS_DISABLE_TO_ENABLE ||
  			lastmaterial.NormalizeNormals != material.NormalizeNormals)
  		{
  			if (material.NormalizeNormals)
  				glEnable(GL_NORMALIZE);
  			else
  				glDisable(GL_NORMALIZE);
  		}
  
  		// Set fixed pipeline as active.
  		tempState = EOFPS_ENABLE;
  	}
  	else if (tempState == EOFPS_ENABLE_TO_DISABLE)
  	{
  		glDisable(GL_COLOR_MATERIAL);
  		glDisable(GL_LIGHTING);
  		glDisable(GL_FOG);
  		glDisable(GL_NORMALIZE);
  
  		// Set programmable pipeline as active.
  		tempState = EOFPS_DISABLE;
  	}
  
  	// tempState == EOFPS_DISABLE - driver doesn't calls functions related to fixed pipeline.
  
  	// fillmode - fixed pipeline call, but it emulate GL_LINES behaviour in rendering, so it stay here.
  	if (resetAllRenderStates || (lastmaterial.Wireframe != material.Wireframe) || (lastmaterial.PointCloud != material.PointCloud))
  		glPolygonMode(GL_FRONT_AND_BACK, material.Wireframe ? GL_LINE : material.PointCloud? GL_POINT : GL_FILL);
  
  	// ZBuffer
  	switch (material.ZBuffer)
  	{
  	case ECFN_DISABLED:
  		CacheHandler->setDepthTest(false);
  		break;
  	case ECFN_LESSEQUAL:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_LEQUAL);
  		break;
  	case ECFN_EQUAL:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_EQUAL);
  		break;
  	case ECFN_LESS:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_LESS);
  		break;
  	case ECFN_NOTEQUAL:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_NOTEQUAL);
  		break;
  	case ECFN_GREATEREQUAL:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_GEQUAL);
  		break;
  	case ECFN_GREATER:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_GREATER);
  		break;
  	case ECFN_ALWAYS:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_ALWAYS);
  		break;
  	case ECFN_NEVER:
  		CacheHandler->setDepthTest(true);
  		CacheHandler->setDepthFunc(GL_NEVER);
  		break;
  	default:
  		break;
  	}
  
  	// ZWrite
  	if (getWriteZBuffer(material))
  	{
  		CacheHandler->setDepthMask(true);
  	}
  	else
  	{
  		CacheHandler->setDepthMask(false);
  	}
  
  	// Back face culling
  	if ((material.FrontfaceCulling) && (material.BackfaceCulling))
  	{
  		CacheHandler->setCullFaceFunc(GL_FRONT_AND_BACK);
  		CacheHandler->setCullFace(true);
  	}
  	else if (material.BackfaceCulling)
  	{
  		CacheHandler->setCullFaceFunc(GL_BACK);
  		CacheHandler->setCullFace(true);
  	}
  	else if (material.FrontfaceCulling)
  	{
  		CacheHandler->setCullFaceFunc(GL_FRONT);
  		CacheHandler->setCullFace(true);
  	}
  	else
  	{
  		CacheHandler->setCullFace(false);
  	}
  
  	// Color Mask
  	CacheHandler->setColorMask(material.ColorMask);
  
  	// Blend Equation
      if (material.BlendOperation == EBO_NONE)
          CacheHandler->setBlend(false);
      else
      {
          CacheHandler->setBlend(true);
  
  #if defined(GL_EXT_blend_subtract) || defined(GL_EXT_blend_minmax) || defined(GL_EXT_blend_logic_op) || defined(GL_VERSION_1_4)
          if (queryFeature(EVDF_BLEND_OPERATIONS))
          {
              switch (material.BlendOperation)
              {
              case EBO_SUBTRACT:
  #if defined(GL_VERSION_1_4)
                  CacheHandler->setBlendEquation(GL_FUNC_SUBTRACT);
  #elif defined(GL_EXT_blend_subtract)
                  CacheHandler->setBlendEquation(GL_FUNC_SUBTRACT_EXT);
  #endif
                  break;
              case EBO_REVSUBTRACT:
  #if defined(GL_VERSION_1_4)
                  CacheHandler->setBlendEquation(GL_FUNC_REVERSE_SUBTRACT);
  #elif defined(GL_EXT_blend_subtract)
                  CacheHandler->setBlendEquation(GL_FUNC_REVERSE_SUBTRACT_EXT);
  #endif
                  break;
              case EBO_MIN:
  #if defined(GL_VERSION_1_4)
                  CacheHandler->setBlendEquation(GL_MIN);
  #elif defined(GL_EXT_blend_minmax)
                  CacheHandler->setBlendEquation(GL_MIN_EXT);
  #endif
                  break;
              case EBO_MAX:
  #if defined(GL_VERSION_1_4)
                  CacheHandler->setBlendEquation(GL_MAX);
  #elif defined(GL_EXT_blend_minmax)
                  CacheHandler->setBlendEquation(GL_MAX_EXT);
  #endif
                  break;
              case EBO_MIN_FACTOR:
  #if defined(GL_AMD_blend_minmax_factor)
                  if (FeatureAvailable[IRR_AMD_blend_minmax_factor])
                      CacheHandler->setBlendEquation(GL_FACTOR_MIN_AMD);
  #endif
  				// fallback in case of missing extension
  #if defined(GL_VERSION_1_4)
  #if defined(GL_AMD_blend_minmax_factor)
                  else
  #endif
                      CacheHandler->setBlendEquation(GL_MIN);
  #endif
                  break;
              case EBO_MAX_FACTOR:
  #if defined(GL_AMD_blend_minmax_factor)
                  if (FeatureAvailable[IRR_AMD_blend_minmax_factor])
                      CacheHandler->setBlendEquation(GL_FACTOR_MAX_AMD);
  #endif
  				// fallback in case of missing extension
  #if defined(GL_VERSION_1_4)
  #if defined(GL_AMD_blend_minmax_factor)
                  else
  #endif
                      CacheHandler->setBlendEquation(GL_MAX);
  #endif
                  break;
              case EBO_MIN_ALPHA:
  #if defined(GL_SGIX_blend_alpha_minmax)
                  if (FeatureAvailable[IRR_SGIX_blend_alpha_minmax])
                      CacheHandler->setBlendEquation(GL_ALPHA_MIN_SGIX);
                  // fallback in case of missing extension
                  else
                      if (FeatureAvailable[IRR_EXT_blend_minmax])
                          CacheHandler->setBlendEquation(GL_MIN_EXT);
  #endif
                  break;
              case EBO_MAX_ALPHA:
  #if defined(GL_SGIX_blend_alpha_minmax)
                  if (FeatureAvailable[IRR_SGIX_blend_alpha_minmax])
                      CacheHandler->setBlendEquation(GL_ALPHA_MAX_SGIX);
                  // fallback in case of missing extension
                  else
                      if (FeatureAvailable[IRR_EXT_blend_minmax])
                          CacheHandler->setBlendEquation(GL_MAX_EXT);
  #endif
                  break;
              default:
  #if defined(GL_VERSION_1_4)
                  CacheHandler->setBlendEquation(GL_FUNC_ADD);
  #elif defined(GL_EXT_blend_subtract) || defined(GL_EXT_blend_minmax) || defined(GL_EXT_blend_logic_op)
                  CacheHandler->setBlendEquation(GL_FUNC_ADD_EXT);
  #endif
                  break;
              }
  		}
  #endif
  	}
  
      // Blend Factor
  	if (IR(material.BlendFactor) & 0xFFFFFFFF)
  	{
          E_BLEND_FACTOR srcRGBFact = EBF_ZERO;
          E_BLEND_FACTOR dstRGBFact = EBF_ZERO;
          E_BLEND_FACTOR srcAlphaFact = EBF_ZERO;
          E_BLEND_FACTOR dstAlphaFact = EBF_ZERO;
          E_MODULATE_FUNC modulo = EMFN_MODULATE_1X;
          u32 alphaSource = 0;
  
          unpack_textureBlendFuncSeparate(srcRGBFact, dstRGBFact, srcAlphaFact, dstAlphaFact, modulo, alphaSource, material.BlendFactor);
  
          if (queryFeature(EVDF_BLEND_SEPARATE))
          {
              CacheHandler->setBlendFuncSeparate(getGLBlend(srcRGBFact), getGLBlend(dstRGBFact),
                  getGLBlend(srcAlphaFact), getGLBlend(dstAlphaFact));
          }
          else
          {
              CacheHandler->setBlendFunc(getGLBlend(srcRGBFact), getGLBlend(dstRGBFact));
          }
  	}
  
  	// Polygon Offset
  	if (queryFeature(EVDF_POLYGON_OFFSET) && (resetAllRenderStates ||
  		lastmaterial.PolygonOffsetDirection != material.PolygonOffsetDirection ||
  		lastmaterial.PolygonOffsetFactor != material.PolygonOffsetFactor))
  	{
  		glDisable(lastmaterial.Wireframe?GL_POLYGON_OFFSET_LINE:lastmaterial.PointCloud?GL_POLYGON_OFFSET_POINT:GL_POLYGON_OFFSET_FILL);
  		if (material.PolygonOffsetFactor)
  		{
  			glDisable(material.Wireframe?GL_POLYGON_OFFSET_LINE:material.PointCloud?GL_POLYGON_OFFSET_POINT:GL_POLYGON_OFFSET_FILL);
  			glEnable(material.Wireframe?GL_POLYGON_OFFSET_LINE:material.PointCloud?GL_POLYGON_OFFSET_POINT:GL_POLYGON_OFFSET_FILL);
  		}
  		if (material.PolygonOffsetDirection==EPO_BACK)
  			glPolygonOffset(1.0f, (GLfloat)material.PolygonOffsetFactor);
  		else
  			glPolygonOffset(-1.0f, (GLfloat)-material.PolygonOffsetFactor);
  	}
  
  	// thickness
  	if (resetAllRenderStates || lastmaterial.Thickness != material.Thickness)
  	{
  		if (AntiAlias)
  		{
  //			glPointSize(core::clamp(static_cast<GLfloat>(material.Thickness), DimSmoothedPoint[0], DimSmoothedPoint[1]));
  			// we don't use point smoothing
  			glPointSize(core::clamp(static_cast<GLfloat>(material.Thickness), DimAliasedPoint[0], DimAliasedPoint[1]));
  			glLineWidth(core::clamp(static_cast<GLfloat>(material.Thickness), DimSmoothedLine[0], DimSmoothedLine[1]));
  		}
  		else
  		{
  			glPointSize(core::clamp(static_cast<GLfloat>(material.Thickness), DimAliasedPoint[0], DimAliasedPoint[1]));
  			glLineWidth(core::clamp(static_cast<GLfloat>(material.Thickness), DimAliasedLine[0], DimAliasedLine[1]));
  		}
  	}
  
  	// Anti aliasing
  	if (resetAllRenderStates || lastmaterial.AntiAliasing != material.AntiAliasing)
  	{
  		if (FeatureAvailable[IRR_ARB_multisample])
  		{
  			if (material.AntiAliasing & EAAM_ALPHA_TO_COVERAGE)
  				glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE_ARB);
  			else if (lastmaterial.AntiAliasing & EAAM_ALPHA_TO_COVERAGE)
  				glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE_ARB);
  
  			if ((AntiAlias >= 2) && (material.AntiAliasing & (EAAM_SIMPLE|EAAM_QUALITY)))
  			{
  				glEnable(GL_MULTISAMPLE_ARB);
  #ifdef GL_NV_multisample_filter_hint
  				if (FeatureAvailable[IRR_NV_multisample_filter_hint])
  				{
  					if ((material.AntiAliasing & EAAM_QUALITY) == EAAM_QUALITY)
  						glHint(GL_MULTISAMPLE_FILTER_HINT_NV, GL_NICEST);
  					else
  						glHint(GL_MULTISAMPLE_FILTER_HINT_NV, GL_NICEST);
  				}
  #endif
  			}
  			else
  				glDisable(GL_MULTISAMPLE_ARB);
  		}
  		if ((material.AntiAliasing & EAAM_LINE_SMOOTH) != (lastmaterial.AntiAliasing & EAAM_LINE_SMOOTH))
  		{
  			if (material.AntiAliasing & EAAM_LINE_SMOOTH)
  				glEnable(GL_LINE_SMOOTH);
  			else if (lastmaterial.AntiAliasing & EAAM_LINE_SMOOTH)
  				glDisable(GL_LINE_SMOOTH);
  		}
  		if ((material.AntiAliasing & EAAM_POINT_SMOOTH) != (lastmaterial.AntiAliasing & EAAM_POINT_SMOOTH))
  		{
  			if (material.AntiAliasing & EAAM_POINT_SMOOTH)
  				// often in software, and thus very slow
  				glEnable(GL_POINT_SMOOTH);
  			else if (lastmaterial.AntiAliasing & EAAM_POINT_SMOOTH)
  				glDisable(GL_POINT_SMOOTH);
  		}
  	}
  
  	// Texture parameters
  	setTextureRenderStates(material, resetAllRenderStates);
  
  	// set current fixed pipeline state
  	FixedPipelineState = tempState;
  }
  
  //! Compare in SMaterial doesn't check texture parameters, so we should call this on each OnRender call.
  void COpenGLDriver::setTextureRenderStates(const SMaterial& material, bool resetAllRenderstates)
  {
  	// Set textures to TU/TIU and apply filters to them
  
  	for (s32 i = Feature.TextureUnit - 1; i >= 0; --i)
  	{
  		bool fixedPipeline = false;
  
  		if (FixedPipelineState == EOFPS_ENABLE || FixedPipelineState == EOFPS_DISABLE_TO_ENABLE)
  			fixedPipeline = true;
  
  		const COpenGLTexture* tmpTexture = CacheHandler->getTextureCache().get(i);
  
  		if (tmpTexture)
  		{
  			CacheHandler->setActiveTexture(GL_TEXTURE0 + i);
  
  			if (fixedPipeline)
  			{
  				const bool isRTT = tmpTexture->isRenderTarget();
  
  				CacheHandler->setMatrixMode(GL_TEXTURE);
  
  				if (!isRTT && Matrices[ETS_TEXTURE_0 + i].isIdentity())
  					glLoadIdentity();
  				else
  				{
  					GLfloat glmat[16];
  					if (isRTT)
  						getGLTextureMatrix(glmat, Matrices[ETS_TEXTURE_0 + i] * TextureFlipMatrix);
  					else
  						getGLTextureMatrix(glmat, Matrices[ETS_TEXTURE_0 + i]);
  					glLoadMatrixf(glmat);
  				}
  			}
  
  			const GLenum tmpType = tmpTexture->getOpenGLTextureType();
  
  			COpenGLTexture::SStatesCache& statesCache = tmpTexture->getStatesCache();
  
  			if (resetAllRenderstates)
  				statesCache.IsCached = false;
  
  #ifdef GL_VERSION_2_1
  			if (Version >= 210)
  			{
  				if (!statesCache.IsCached || material.TextureLayer[i].LODBias != statesCache.LODBias)
  				{
  					if (material.TextureLayer[i].LODBias)
  					{
  						const float tmp = core::clamp(material.TextureLayer[i].LODBias * 0.125f, -MaxTextureLODBias, MaxTextureLODBias);
  						glTexParameterf(tmpType, GL_TEXTURE_LOD_BIAS, tmp);
  					}
  					else
  						glTexParameterf(tmpType, GL_TEXTURE_LOD_BIAS, 0.f);
  
  					statesCache.LODBias = material.TextureLayer[i].LODBias;
  				}
  			}
  			else if (FeatureAvailable[IRR_EXT_texture_lod_bias])
  			{
  				if (material.TextureLayer[i].LODBias)
  				{
  					const float tmp = core::clamp(material.TextureLayer[i].LODBias * 0.125f, -MaxTextureLODBias, MaxTextureLODBias);
  					glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, tmp);
  				}
  				else
  					glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, 0.f);
  			}
  #elif defined(GL_EXT_texture_lod_bias)
  			if (FeatureAvailable[IRR_EXT_texture_lod_bias])
  			{
  				if (material.TextureLayer[i].LODBias)
  				{
  					const float tmp = core::clamp(material.TextureLayer[i].LODBias * 0.125f, -MaxTextureLODBias, MaxTextureLODBias);
  					glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, tmp);
  				}
  				else
  					glTexEnvf(GL_TEXTURE_FILTER_CONTROL_EXT, GL_TEXTURE_LOD_BIAS_EXT, 0.f);
  			}
  #endif
  
  			if (!statesCache.IsCached || material.TextureLayer[i].BilinearFilter != statesCache.BilinearFilter ||
  				material.TextureLayer[i].TrilinearFilter != statesCache.TrilinearFilter)
  			{
  				glTexParameteri(tmpType, GL_TEXTURE_MAG_FILTER,
  					(material.TextureLayer[i].BilinearFilter || material.TextureLayer[i].TrilinearFilter) ? GL_LINEAR : GL_NEAREST);
  
  				statesCache.BilinearFilter = material.TextureLayer[i].BilinearFilter;
  				statesCache.TrilinearFilter = material.TextureLayer[i].TrilinearFilter;
  			}
  
  			if (material.UseMipMaps && tmpTexture->hasMipMaps())
  			{
  				if (!statesCache.IsCached || material.TextureLayer[i].BilinearFilter != statesCache.BilinearFilter ||
  					material.TextureLayer[i].TrilinearFilter != statesCache.TrilinearFilter || !statesCache.MipMapStatus)
  				{
  					glTexParameteri(tmpType, GL_TEXTURE_MIN_FILTER,
  						material.TextureLayer[i].TrilinearFilter ? GL_LINEAR_MIPMAP_LINEAR :
  						material.TextureLayer[i].BilinearFilter ? GL_LINEAR_MIPMAP_NEAREST :
  						GL_NEAREST_MIPMAP_NEAREST);
  
  					statesCache.BilinearFilter = material.TextureLayer[i].BilinearFilter;
  					statesCache.TrilinearFilter = material.TextureLayer[i].TrilinearFilter;
  					statesCache.MipMapStatus = true;
  				}
  			}
  			else
  			{
  				if (!statesCache.IsCached || material.TextureLayer[i].BilinearFilter != statesCache.BilinearFilter ||
  					material.TextureLayer[i].TrilinearFilter != statesCache.TrilinearFilter || statesCache.MipMapStatus)
  				{
  					glTexParameteri(tmpType, GL_TEXTURE_MIN_FILTER,
  						(material.TextureLayer[i].BilinearFilter || material.TextureLayer[i].TrilinearFilter) ? GL_LINEAR : GL_NEAREST);
  
  					statesCache.BilinearFilter = material.TextureLayer[i].BilinearFilter;
  					statesCache.TrilinearFilter = material.TextureLayer[i].TrilinearFilter;
  					statesCache.MipMapStatus = false;
  				}
  			}
  
  #ifdef GL_EXT_texture_filter_anisotropic
  			if (FeatureAvailable[IRR_EXT_texture_filter_anisotropic] &&
  				(!statesCache.IsCached || material.TextureLayer[i].AnisotropicFilter != statesCache.AnisotropicFilter))
  			{
  				glTexParameteri(tmpType, GL_TEXTURE_MAX_ANISOTROPY_EXT,
  					material.TextureLayer[i].AnisotropicFilter > 1 ? core::min_(MaxAnisotropy, material.TextureLayer[i].AnisotropicFilter) : 1);
  
  				statesCache.AnisotropicFilter = material.TextureLayer[i].AnisotropicFilter;
  			}
  #endif
  
  			if (!statesCache.IsCached || material.TextureLayer[i].TextureWrapU != statesCache.WrapU)
  			{
  				glTexParameteri(tmpType, GL_TEXTURE_WRAP_S, getTextureWrapMode(material.TextureLayer[i].TextureWrapU));
  				statesCache.WrapU = material.TextureLayer[i].TextureWrapU;
  			}
  
  			if (!statesCache.IsCached || material.TextureLayer[i].TextureWrapV != statesCache.WrapV)
  			{
  				glTexParameteri(tmpType, GL_TEXTURE_WRAP_T, getTextureWrapMode(material.TextureLayer[i].TextureWrapV));
  				statesCache.WrapV = material.TextureLayer[i].TextureWrapV;
  			}
  
  			if (!statesCache.IsCached || material.TextureLayer[i].TextureWrapW != statesCache.WrapW)
  			{
  				glTexParameteri(tmpType, GL_TEXTURE_WRAP_R, getTextureWrapMode(material.TextureLayer[i].TextureWrapW));
  				statesCache.WrapW = material.TextureLayer[i].TextureWrapW;
  			}
  
  			statesCache.IsCached = true;
  		}
  	}
  }
  
  
  //! Enable the 2d override material
  void COpenGLDriver::enableMaterial2D(bool enable)
  {
  	if (!enable)
  		CurrentRenderMode = ERM_NONE;
  	CNullDriver::enableMaterial2D(enable);
  }
  
  
  //! sets the needed renderstates
  void COpenGLDriver::setRenderStates2DMode(bool alpha, bool texture, bool alphaChannel)
  {
  	// 2d methods uses fixed pipeline
  	if (FixedPipelineState == COpenGLDriver::EOFPS_DISABLE)
  		FixedPipelineState = COpenGLDriver::EOFPS_DISABLE_TO_ENABLE;
  	else
  		FixedPipelineState = COpenGLDriver::EOFPS_ENABLE;
  
  	bool resetAllRenderStates = false;
  
  	if (CurrentRenderMode != ERM_2D || Transformation3DChanged)
  	{
  		// unset last 3d material
  		if (CurrentRenderMode == ERM_3D)
  		{
  			if (static_cast<u32>(LastMaterial.MaterialType) < MaterialRenderers.size())
  				MaterialRenderers[LastMaterial.MaterialType].Renderer->OnUnsetMaterial();
  		}
  
  		if (Transformation3DChanged)
  		{
  			CacheHandler->setMatrixMode(GL_PROJECTION);
  
  			const core::dimension2d<u32>& renderTargetSize = getCurrentRenderTargetSize();
  			core::matrix4 m(core::matrix4::EM4CONST_NOTHING);
  			m.buildProjectionMatrixOrthoLH(f32(renderTargetSize.Width), f32(-(s32)(renderTargetSize.Height)), -1.0f, 1.0f);
  			m.setTranslation(core::vector3df(-1,1,0));
  			glLoadMatrixf(m.pointer());
  
  			CacheHandler->setMatrixMode(GL_MODELVIEW);
  			glLoadIdentity();
  			glTranslatef(0.375f, 0.375f, 0.0f);
  
  			Transformation3DChanged = false;
  		}
  
  		CacheHandler->setBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  
  #ifdef GL_EXT_clip_volume_hint
  		if (FeatureAvailable[IRR_EXT_clip_volume_hint])
  			glHint(GL_CLIP_VOLUME_CLIPPING_HINT_EXT, GL_FASTEST);
  #endif
  
  		resetAllRenderStates = true;
  	}
  
  	SMaterial currentMaterial = (!OverrideMaterial2DEnabled) ? InitMaterial2D : OverrideMaterial2D;
  	currentMaterial.Lighting = false;
  
  	if (texture)
  	{
  		setTransform(ETS_TEXTURE_0, core::IdentityMatrix);
  
  		// Due to the transformation change, the previous line would call a reset each frame
  		// but we can safely reset the variable as it was false before
  		Transformation3DChanged = false;
  	}
  	else
  	{
  		CacheHandler->getTextureCache().set(0, 0);
  	}
  
  	setBasicRenderStates(currentMaterial, LastMaterial, resetAllRenderStates);
  
  	LastMaterial = currentMaterial;
  
  	// no alphaChannel without texture
  	alphaChannel &= texture;
  
  	if (alphaChannel || alpha)
  	{
  		CacheHandler->setBlend(true);
  		CacheHandler->setAlphaTest(true);
  		CacheHandler->setAlphaFunc(GL_GREATER, 0.f);
  	}
  	else
  	{
  		CacheHandler->setBlend(false);
  		CacheHandler->setAlphaTest(false);
  	}
  
  	if (texture)
  	{
  		CacheHandler->setActiveTexture(GL_TEXTURE0_ARB);
  
  		if (alphaChannel)
  		{
  			// if alpha and alpha texture just modulate, otherwise use only the alpha channel
  			if (alpha)
  			{
  				glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  			}
  			else
  			{
  #if defined(GL_ARB_texture_env_combine) || defined(GL_EXT_texture_env_combine)
  				if (FeatureAvailable[IRR_ARB_texture_env_combine]||FeatureAvailable[IRR_EXT_texture_env_combine])
  				{
  #ifdef GL_ARB_texture_env_combine
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE);
  					// rgb always modulates
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PRIMARY_COLOR_ARB);
  #else
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_EXT, GL_REPLACE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_EXT, GL_TEXTURE);
  					// rgb always modulates
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_EXT, GL_MODULATE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_EXT, GL_TEXTURE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_EXT, GL_PRIMARY_COLOR_EXT);
  #endif
  				}
  				else
  #endif
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  			}
  		}
  		else
  		{
  			if (alpha)
  			{
  #if defined(GL_ARB_texture_env_combine) || defined(GL_EXT_texture_env_combine)
  				if (FeatureAvailable[IRR_ARB_texture_env_combine]||FeatureAvailable[IRR_EXT_texture_env_combine])
  				{
  #ifdef GL_ARB_texture_env_combine
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PRIMARY_COLOR_ARB);
  					// rgb always modulates
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PRIMARY_COLOR_ARB);
  #else
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_EXT);
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA_EXT, GL_REPLACE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_EXT, GL_PRIMARY_COLOR_EXT);
  					// rgb always modulates
  					glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB_EXT, GL_MODULATE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_EXT, GL_TEXTURE);
  					glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_EXT, GL_PRIMARY_COLOR_EXT);
  #endif
  				}
  				else
  #endif
  					glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  			}
  			else
  			{
  				glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  			}
  		}
  	}
  
  	CurrentRenderMode = ERM_2D;
  }
  
  
  //! \return Returns the name of the video driver.
  const wchar_t* COpenGLDriver::getName() const
  {
  	return Name.c_str();
  }
  
  
  //! deletes all dynamic lights there are
  void COpenGLDriver::deleteAllDynamicLights()
  {
  	for (s32 i=0; i<MaxLights; ++i)
  		glDisable(GL_LIGHT0 + i);
  
  	RequestedLights.clear();
  
  	CNullDriver::deleteAllDynamicLights();
  }
  
  
  //! adds a dynamic light
  s32 COpenGLDriver::addDynamicLight(const SLight& light)
  {
  	CNullDriver::addDynamicLight(light);
  
  	RequestedLights.push_back(RequestedLight(light));
  
  	u32 newLightIndex = RequestedLights.size() - 1;
  
  	// Try and assign a hardware light just now, but don't worry if I can't
  	assignHardwareLight(newLightIndex);
  
  	return (s32)newLightIndex;
  }
  
  
  void COpenGLDriver::assignHardwareLight(u32 lightIndex)
  {
  	setTransform(ETS_WORLD, core::matrix4());
  
  	s32 lidx;
  	for (lidx=GL_LIGHT0; lidx < GL_LIGHT0 + MaxLights; ++lidx)
  	{
  		if(!glIsEnabled(lidx))
  		{
  			RequestedLights[lightIndex].HardwareLightIndex = lidx;
  			break;
  		}
  	}
  
  	if(lidx == GL_LIGHT0 + MaxLights) // There's no room for it just now
  		return;
  
  	GLfloat data[4];
  	const SLight & light = RequestedLights[lightIndex].LightData;
  
  	switch (light.Type)
  	{
  	case video::ELT_SPOT:
  		data[0] = light.Direction.X;
  		data[1] = light.Direction.Y;
  		data[2] = light.Direction.Z;
  		data[3] = 0.0f;
  		glLightfv(lidx, GL_SPOT_DIRECTION, data);
  
  		// set position
  		data[0] = light.Position.X;
  		data[1] = light.Position.Y;
  		data[2] = light.Position.Z;
  		data[3] = 1.0f; // 1.0f for positional light
  		glLightfv(lidx, GL_POSITION, data);
  
  		glLightf(lidx, GL_SPOT_EXPONENT, light.Falloff);
  		glLightf(lidx, GL_SPOT_CUTOFF, light.OuterCone);
  	break;
  	case video::ELT_POINT:
  		// set position
  		data[0] = light.Position.X;
  		data[1] = light.Position.Y;
  		data[2] = light.Position.Z;
  		data[3] = 1.0f; // 1.0f for positional light
  		glLightfv(lidx, GL_POSITION, data);
  
  		glLightf(lidx, GL_SPOT_EXPONENT, 0.0f);
  		glLightf(lidx, GL_SPOT_CUTOFF, 180.0f);
  	break;
  	case video::ELT_DIRECTIONAL:
  		// set direction
  		data[0] = -light.Direction.X;
  		data[1] = -light.Direction.Y;
  		data[2] = -light.Direction.Z;
  		data[3] = 0.0f; // 0.0f for directional light
  		glLightfv(lidx, GL_POSITION, data);
  
  		glLightf(lidx, GL_SPOT_EXPONENT, 0.0f);
  		glLightf(lidx, GL_SPOT_CUTOFF, 180.0f);
  	break;
  	default:
  	break;
  	}
  
  	// set diffuse color
  	data[0] = light.DiffuseColor.r;
  	data[1] = light.DiffuseColor.g;
  	data[2] = light.DiffuseColor.b;
  	data[3] = light.DiffuseColor.a;
  	glLightfv(lidx, GL_DIFFUSE, data);
  
  	// set specular color
  	data[0] = light.SpecularColor.r;
  	data[1] = light.SpecularColor.g;
  	data[2] = light.SpecularColor.b;
  	data[3] = light.SpecularColor.a;
  	glLightfv(lidx, GL_SPECULAR, data);
  
  	// set ambient color
  	data[0] = light.AmbientColor.r;
  	data[1] = light.AmbientColor.g;
  	data[2] = light.AmbientColor.b;
  	data[3] = light.AmbientColor.a;
  	glLightfv(lidx, GL_AMBIENT, data);
  
  	// 1.0f / (constant + linear * d + quadratic*(d*d);
  
  	// set attenuation
  	glLightf(lidx, GL_CONSTANT_ATTENUATION, light.Attenuation.X);
  	glLightf(lidx, GL_LINEAR_ATTENUATION, light.Attenuation.Y);
  	glLightf(lidx, GL_QUADRATIC_ATTENUATION, light.Attenuation.Z);
  
  	glEnable(lidx);
  }
  
  
  //! Turns a dynamic light on or off
  //! \param lightIndex: the index returned by addDynamicLight
  //! \param turnOn: true to turn the light on, false to turn it off
  void COpenGLDriver::turnLightOn(s32 lightIndex, bool turnOn)
  {
  	if(lightIndex < 0 || lightIndex >= (s32)RequestedLights.size())
  		return;
  
  	RequestedLight & requestedLight = RequestedLights[lightIndex];
  
  	requestedLight.DesireToBeOn = turnOn;
  
  	if(turnOn)
  	{
  		if(-1 == requestedLight.HardwareLightIndex)
  			assignHardwareLight(lightIndex);
  	}
  	else
  	{
  		if(-1 != requestedLight.HardwareLightIndex)
  		{
  			// It's currently assigned, so free up the hardware light
  			glDisable(requestedLight.HardwareLightIndex);
  			requestedLight.HardwareLightIndex = -1;
  
  			// Now let the first light that's waiting on a free hardware light grab it
  			for(u32 requested = 0; requested < RequestedLights.size(); ++requested)
  				if(RequestedLights[requested].DesireToBeOn
  					&&
  					-1 == RequestedLights[requested].HardwareLightIndex)
  				{
  					assignHardwareLight(requested);
  					break;
  				}
  		}
  	}
  }
  
  
  //! returns the maximal amount of dynamic lights the device can handle
  u32 COpenGLDriver::getMaximalDynamicLightAmount() const
  {
  	return MaxLights;
  }
  
  
  //! Sets the dynamic ambient light color. The default color is
  //! (0,0,0,0) which means it is dark.
  //! \param color: New color of the ambient light.
  void COpenGLDriver::setAmbientLight(const SColorf& color)
  {
  	GLfloat data[4] = {color.r, color.g, color.b, color.a};
  	glLightModelfv(GL_LIGHT_MODEL_AMBIENT, data);
  }
  
  
  // this code was sent in by Oliver Klems, thank you! (I modified the glViewport
  // method just a bit.
  void COpenGLDriver::setViewPort(const core::rect<s32>& area)
  {
  	core::rect<s32> vp = area;
  	core::rect<s32> rendert(0, 0, getCurrentRenderTargetSize().Width, getCurrentRenderTargetSize().Height);
  	vp.clipAgainst(rendert);
  
  	if (vp.getHeight() > 0 && vp.getWidth() > 0)
  		CacheHandler->setViewport(vp.UpperLeftCorner.X, getCurrentRenderTargetSize().Height - vp.UpperLeftCorner.Y - vp.getHeight(), vp.getWidth(), vp.getHeight());
  
  	ViewPort = vp;
  }
  
  
  //! Draws a shadow volume into the stencil buffer. To draw a stencil shadow, do
  //! this: First, draw all geometry. Then use this method, to draw the shadow
  //! volume. Next use IVideoDriver::drawStencilShadow() to visualize the shadow.
  void COpenGLDriver::drawStencilShadowVolume(const core::array<core::vector3df>& triangles, bool zfail, u32 debugDataVisible)
  {
  	const u32 count=triangles.size();
  	if (!StencilBuffer || !count)
  		return;
  
  	// unset last 3d material
  	if (CurrentRenderMode == ERM_3D &&
  		static_cast<u32>(Material.MaterialType) < MaterialRenderers.size())
  	{
  		MaterialRenderers[Material.MaterialType].Renderer->OnUnsetMaterial();
  		ResetRenderStates = true;
  	}
  
  	// store current OpenGL state
  	glPushAttrib(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT |
  		GL_POLYGON_BIT | GL_STENCIL_BUFFER_BIT);
  
  	glDisable(GL_LIGHTING);
  	glDisable(GL_FOG);
  	glEnable(GL_DEPTH_TEST);
  	glDepthFunc(GL_LESS);
  	glDepthMask(GL_FALSE);
  
  	if (debugDataVisible & scene::EDS_MESH_WIRE_OVERLAY)
  		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
  	if (!(debugDataVisible & (scene::EDS_SKELETON|scene::EDS_MESH_WIRE_OVERLAY)))
  	{
  		glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE); // no color buffer drawing
  		glEnable(GL_STENCIL_TEST);
  	}
  
  	CacheHandler->setClientState(true, false, false, false);
  	glVertexPointer(3,GL_FLOAT,sizeof(core::vector3df),triangles.const_pointer());
  	glStencilMask(~0);
  	glStencilFunc(GL_ALWAYS, 0, ~0);
  
  	GLenum incr = GL_INCR;
  	GLenum decr = GL_DECR;
  #ifdef GL_EXT_stencil_wrap
  	if (FeatureAvailable[IRR_EXT_stencil_wrap])
  	{
  		incr = GL_INCR_WRAP_EXT;
  		decr = GL_DECR_WRAP_EXT;
  	}
  #endif
  #ifdef GL_NV_depth_clamp
  	if (FeatureAvailable[IRR_NV_depth_clamp])
  		glEnable(GL_DEPTH_CLAMP_NV);
  #endif
  
  	// The first parts are not correctly working, yet.
  #if 0
  #ifdef GL_EXT_stencil_two_side
  	if (FeatureAvailable[IRR_EXT_stencil_two_side])
  	{
  		glEnable(GL_STENCIL_TEST_TWO_SIDE_EXT);
  		glDisable(GL_CULL_FACE);
  		if (zfail)
  		{
  			extGlActiveStencilFace(GL_BACK);
  			glStencilOp(GL_KEEP, incr, GL_KEEP);
  			glStencilMask(~0);
  			glStencilFunc(GL_ALWAYS, 0, ~0);
  
  			extGlActiveStencilFace(GL_FRONT);
  			glStencilOp(GL_KEEP, decr, GL_KEEP);
  		}
  		else // zpass
  		{
  			extGlActiveStencilFace(GL_BACK);
  			glStencilOp(GL_KEEP, GL_KEEP, decr);
  			glStencilMask(~0);
  			glStencilFunc(GL_ALWAYS, 0, ~0);
  
  			extGlActiveStencilFace(GL_FRONT);
  			glStencilOp(GL_KEEP, GL_KEEP, incr);
  		}
  		glStencilMask(~0);
  		glStencilFunc(GL_ALWAYS, 0, ~0);
  		glDrawArrays(GL_TRIANGLES,0,count);
  		glDisable(GL_STENCIL_TEST_TWO_SIDE_EXT);
  	}
  	else
  #endif
  	if (FeatureAvailable[IRR_ATI_separate_stencil])
  	{
  		glDisable(GL_CULL_FACE);
  		if (zfail)
  		{
  			extGlStencilOpSeparate(GL_BACK, GL_KEEP, incr, GL_KEEP);
  			extGlStencilOpSeparate(GL_FRONT, GL_KEEP, decr, GL_KEEP);
  		}
  		else // zpass
  		{
  			extGlStencilOpSeparate(GL_BACK, GL_KEEP, GL_KEEP, decr);
  			extGlStencilOpSeparate(GL_FRONT, GL_KEEP, GL_KEEP, incr);
  		}
  		extGlStencilFuncSeparate(GL_ALWAYS, GL_ALWAYS, 0, ~0);
  		glStencilMask(~0);
  		glDrawArrays(GL_TRIANGLES,0,count);
  	}
  	else
  #endif
  	{
  		glEnable(GL_CULL_FACE);
  		if (zfail)
  		{
  			glCullFace(GL_FRONT);
  			glStencilOp(GL_KEEP, incr, GL_KEEP);
  			glDrawArrays(GL_TRIANGLES,0,count);
  
  			glCullFace(GL_BACK);
  			glStencilOp(GL_KEEP, decr, GL_KEEP);
  			glDrawArrays(GL_TRIANGLES,0,count);
  		}
  		else // zpass
  		{
  			glCullFace(GL_BACK);
  			glStencilOp(GL_KEEP, GL_KEEP, incr);
  			glDrawArrays(GL_TRIANGLES,0,count);
  
  			glCullFace(GL_FRONT);
  			glStencilOp(GL_KEEP, GL_KEEP, decr);
  			glDrawArrays(GL_TRIANGLES,0,count);
  		}
  	}
  #ifdef GL_NV_depth_clamp
  	if (FeatureAvailable[IRR_NV_depth_clamp])
  		glDisable(GL_DEPTH_CLAMP_NV);
  #endif
  
  	glDisable(GL_POLYGON_OFFSET_FILL);
  	glPopAttrib();
  }
  
  //! Fills the stencil shadow with color. After the shadow volume has been drawn
  //! into the stencil buffer using IVideoDriver::drawStencilShadowVolume(), use this
  //! to draw the color of the shadow.
  void COpenGLDriver::drawStencilShadow(bool clearStencilBuffer, video::SColor leftUpEdge,
  	video::SColor rightUpEdge, video::SColor leftDownEdge, video::SColor rightDownEdge)
  {
  	if (!StencilBuffer)
  		return;
  
  	disableTextures();
  
  	// store attributes
  	glPushAttrib(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT | GL_POLYGON_BIT | GL_STENCIL_BUFFER_BIT | GL_LIGHTING_BIT);
  
  	glDisable(GL_LIGHTING);
  	glDisable(GL_FOG);
  	glDepthMask(GL_FALSE);
  
  	glShadeModel(GL_FLAT);
  	glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
  
  	glEnable(GL_BLEND);
  	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  
  	glEnable(GL_STENCIL_TEST);
  	glStencilFunc(GL_NOTEQUAL, 0, ~0);
  	glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
  
  	// draw a shadow rectangle covering the entire screen using stencil buffer
  	CacheHandler->setMatrixMode(GL_MODELVIEW);
  	glPushMatrix();
  	glLoadIdentity();
  	CacheHandler->setMatrixMode(GL_PROJECTION);
  	glPushMatrix();
  	glLoadIdentity();
  
  	Quad2DVertices[0].Color = leftDownEdge;
  	Quad2DVertices[1].Color = leftUpEdge;
  	Quad2DVertices[2].Color = rightUpEdge;
  	Quad2DVertices[3].Color = rightDownEdge;
  
  	Quad2DVertices[0].Pos = core::vector3df(-1.0f, -1.0f, -0.9f);
  	Quad2DVertices[1].Pos = core::vector3df(-1.0f, 1.0f, -0.9f);
  	Quad2DVertices[2].Pos = core::vector3df(1.0f, 1.0f, -0.9f);
  	Quad2DVertices[3].Pos = core::vector3df(1.0f, -1.0f, -0.9f);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 4, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, false);
  
  	glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_SHORT, Quad2DIndices);
  
  	if (clearStencilBuffer)
  		glClear(GL_STENCIL_BUFFER_BIT);
  
  	// restore settings
  	glPopMatrix();
  	CacheHandler->setMatrixMode(GL_MODELVIEW);
  	glPopMatrix();
  	glPopAttrib();
  }
  
  
  //! Sets the fog mode.
  void COpenGLDriver::setFog(SColor c, E_FOG_TYPE fogType, f32 start,
  			f32 end, f32 density, bool pixelFog, bool rangeFog)
  {
  	CNullDriver::setFog(c, fogType, start, end, density, pixelFog, rangeFog);
  
  	glFogf(GL_FOG_MODE, GLfloat((fogType==EFT_FOG_LINEAR)? GL_LINEAR : (fogType==EFT_FOG_EXP)?GL_EXP:GL_EXP2));
  
  #ifdef GL_EXT_fog_coord
  	if (FeatureAvailable[IRR_EXT_fog_coord])
  		glFogi(GL_FOG_COORDINATE_SOURCE, GL_FRAGMENT_DEPTH);
  #endif
  #ifdef GL_NV_fog_distance
  	if (FeatureAvailable[IRR_NV_fog_distance])
  	{
  		if (rangeFog)
  			glFogi(GL_FOG_DISTANCE_MODE_NV, GL_EYE_RADIAL_NV);
  		else
  			glFogi(GL_FOG_DISTANCE_MODE_NV, GL_EYE_PLANE_ABSOLUTE_NV);
  	}
  #endif
  
  	if (fogType==EFT_FOG_LINEAR)
  	{
  		glFogf(GL_FOG_START, start);
  		glFogf(GL_FOG_END, end);
  	}
  	else
  		glFogf(GL_FOG_DENSITY, density);
  
  	if (pixelFog)
  		glHint(GL_FOG_HINT, GL_NICEST);
  	else
  		glHint(GL_FOG_HINT, GL_FASTEST);
  
  	SColorf color(c);
  	GLfloat data[4] = {color.r, color.g, color.b, color.a};
  	glFogfv(GL_FOG_COLOR, data);
  }
  
  //! Draws a 3d box.
  void COpenGLDriver::draw3DBox( const core::aabbox3d<f32>& box, SColor color )
  {
  	core::vector3df edges[8];
  	box.getEdges(edges);
  
  	setRenderStates3DMode();
  
  	video::S3DVertex v[24];
  
  	for(u32 i = 0; i < 24; i++)
  		v[i].Color = color;
  
  	v[0].Pos = edges[5];
  	v[1].Pos = edges[1];
  	v[2].Pos = edges[1];
  	v[3].Pos = edges[3];
  	v[4].Pos = edges[3];
  	v[5].Pos = edges[7];
  	v[6].Pos = edges[7];
  	v[7].Pos = edges[5];
  	v[8].Pos = edges[0];
  	v[9].Pos = edges[2];
  	v[10].Pos = edges[2];
  	v[11].Pos = edges[6];
  	v[12].Pos = edges[6];
  	v[13].Pos = edges[4];
  	v[14].Pos = edges[4];
  	v[15].Pos = edges[0];
  	v[16].Pos = edges[1];
  	v[17].Pos = edges[0];
  	v[18].Pos = edges[3];
  	v[19].Pos = edges[2];
  	v[20].Pos = edges[7];
  	v[21].Pos = edges[6];
  	v[22].Pos = edges[5];
  	v[23].Pos = edges[4];
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(v, 24, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, false);
  
  	glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(v))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(v))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawArrays(GL_LINES, 0, 24);
  }
  
  
  //! Draws a 3d line.
  void COpenGLDriver::draw3DLine(const core::vector3df& start,
  				const core::vector3df& end, SColor color)
  {
  	setRenderStates3DMode();
  
  	Quad2DVertices[0].Color = color;
  	Quad2DVertices[1].Color = color;
  
  	Quad2DVertices[0].Pos = core::vector3df((f32)start.X, (f32)start.Y, (f32)start.Z);
  	Quad2DVertices[1].Pos = core::vector3df((f32)end.X, (f32)end.Y, (f32)end.Z);
  
  	if (!FeatureAvailable[IRR_ARB_vertex_array_bgra] && !FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		getColorBuffer(Quad2DVertices, 2, EVT_STANDARD);
  
  	CacheHandler->setClientState(true, false, true, false);
  
  	glVertexPointer(3, GL_FLOAT, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Pos);
  
  #ifdef GL_BGRA
  	const GLint colorSize=(FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])?GL_BGRA:4;
  #else
  	const GLint colorSize=4;
  #endif
  	if (FeatureAvailable[IRR_ARB_vertex_array_bgra] || FeatureAvailable[IRR_EXT_vertex_array_bgra])
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, sizeof(S3DVertex), &(static_cast<const S3DVertex*>(Quad2DVertices))[0].Color);
  	else
  	{
  		_IRR_DEBUG_BREAK_IF(ColorBuffer.size()==0);
  		glColorPointer(colorSize, GL_UNSIGNED_BYTE, 0, &ColorBuffer[0]);
  	}
  
  	glDrawElements(GL_LINES, 2, GL_UNSIGNED_SHORT, Quad2DIndices);
  }
  
  
  //! Removes a texture from the texture cache and deletes it, freeing lot of memory.
  void COpenGLDriver::removeTexture(ITexture* texture)
  {
  	if (!texture)
  		return;
  
  	CNullDriver::removeTexture(texture);
  }
  
  //! Check if the driver supports creating textures with the given color format
  bool COpenGLDriver::queryTextureFormat(ECOLOR_FORMAT format) const
  {
  	GLint dummyInternalFormat;
  	GLenum dummyPixelFormat;
  	GLenum dummyPixelType;
  	void (*dummyConverter)(const void*, s32, void*);
  	return getColorFormatParameters(format, dummyInternalFormat, dummyPixelFormat, dummyPixelType, &dummyConverter);
  }
  
  //! Only used by the internal engine. Used to notify the driver that
  //! the window was resized.
  void COpenGLDriver::OnResize(const core::dimension2d<u32>& size)
  {
  	CNullDriver::OnResize(size);
  	CacheHandler->setViewport(0, 0, size.Width, size.Height);
  	Transformation3DChanged = true;
  }
  
  
  //! Returns type of video driver
  E_DRIVER_TYPE COpenGLDriver::getDriverType() const
  {
  	return EDT_OPENGL;
  }
  
  
  //! returns color format
  ECOLOR_FORMAT COpenGLDriver::getColorFormat() const
  {
  	return ColorFormat;
  }
  
  
  //! Get a vertex shader constant index.
  s32 COpenGLDriver::getVertexShaderConstantID(const c8* name)
  {
  	return getPixelShaderConstantID(name);
  }
  
  //! Get a pixel shader constant index.
  s32 COpenGLDriver::getPixelShaderConstantID(const c8* name)
  {
  	os::Printer::log("Error: Please call services->getPixelShaderConstantID(), not VideoDriver->getPixelShaderConstantID().");
  	return -1;
  }
  
  //! Sets a vertex shader constant.
  void COpenGLDriver::setVertexShaderConstant(const f32* data, s32 startRegister, s32 constantAmount)
  {
  #ifdef GL_ARB_vertex_program
  	for (s32 i=0; i<constantAmount; ++i)
  		extGlProgramLocalParameter4fv(GL_VERTEX_PROGRAM_ARB, startRegister+i, &data[i*4]);
  #endif
  }
  
  //! Sets a pixel shader constant.
  void COpenGLDriver::setPixelShaderConstant(const f32* data, s32 startRegister, s32 constantAmount)
  {
  #ifdef GL_ARB_fragment_program
  	for (s32 i=0; i<constantAmount; ++i)
  		extGlProgramLocalParameter4fv(GL_FRAGMENT_PROGRAM_ARB, startRegister+i, &data[i*4]);
  #endif
  }
  
  //! Sets a constant for the vertex shader based on an index.
  bool COpenGLDriver::setVertexShaderConstant(s32 index, const f32* floats, int count)
  {
  	//pass this along, as in GLSL the same routine is used for both vertex and fragment shaders
  	return setPixelShaderConstant(index, floats, count);
  }
  
  //! Int interface for the above.
  bool COpenGLDriver::setVertexShaderConstant(s32 index, const s32* ints, int count)
  {
  	return setPixelShaderConstant(index, ints, count);
  }
  
  //! Sets a constant for the pixel shader based on an index.
  bool COpenGLDriver::setPixelShaderConstant(s32 index, const f32* floats, int count)
  {
  	os::Printer::log("Error: Please call services->setPixelShaderConstant(), not VideoDriver->setPixelShaderConstant().");
  	return false;
  }
  
  //! Int interface for the above.
  bool COpenGLDriver::setPixelShaderConstant(s32 index, const s32* ints, int count)
  {
  	os::Printer::log("Error: Please call services->setPixelShaderConstant(), not VideoDriver->setPixelShaderConstant().");
  	return false;
  }
  
  
  //! Adds a new material renderer to the VideoDriver, using pixel and/or
  //! vertex shaders to render geometry.
  s32 COpenGLDriver::addShaderMaterial(const c8* vertexShaderProgram,
  	const c8* pixelShaderProgram,
  	IShaderConstantSetCallBack* callback,
  	E_MATERIAL_TYPE baseMaterial, s32 userData)
  {
  	s32 nr = -1;
  	COpenGLShaderMaterialRenderer* r = new COpenGLShaderMaterialRenderer(
  		this, nr, vertexShaderProgram, pixelShaderProgram,
  		callback, baseMaterial, userData);
  
  	r->drop();
  	return nr;
  }
  
  
  //! Adds a new material renderer to the VideoDriver, using GLSL to render geometry.
  s32 COpenGLDriver::addHighLevelShaderMaterial(
  	const c8* vertexShaderProgram,
  	const c8* vertexShaderEntryPointName,
  	E_VERTEX_SHADER_TYPE vsCompileTarget,
  	const c8* pixelShaderProgram,
  	const c8* pixelShaderEntryPointName,
  	E_PIXEL_SHADER_TYPE psCompileTarget,
  	const c8* geometryShaderProgram,
  	const c8* geometryShaderEntryPointName,
  	E_GEOMETRY_SHADER_TYPE gsCompileTarget,
  	scene::E_PRIMITIVE_TYPE inType,
  	scene::E_PRIMITIVE_TYPE outType,
  	u32 verticesOut,
  	IShaderConstantSetCallBack* callback,
  	E_MATERIAL_TYPE baseMaterial,
  	s32 userData, E_GPU_SHADING_LANGUAGE shadingLang)
  {
  	s32 nr = -1;
  
  	COpenGLSLMaterialRenderer* r = new COpenGLSLMaterialRenderer(
  			this, nr,
  			vertexShaderProgram, vertexShaderEntryPointName, vsCompileTarget,
  			pixelShaderProgram, pixelShaderEntryPointName, psCompileTarget,
  			geometryShaderProgram, geometryShaderEntryPointName, gsCompileTarget,
  			inType, outType, verticesOut,
  			callback,baseMaterial, userData);
  
  	r->drop();
  
  	return nr;
  }
  
  
  //! Returns a pointer to the IVideoDriver interface. (Implementation for
  //! IMaterialRendererServices)
  IVideoDriver* COpenGLDriver::getVideoDriver()
  {
  	return this;
  }
  
  
  ITexture* COpenGLDriver::addRenderTargetTexture(const core::dimension2d<u32>& size,
  	const io::path& name, const ECOLOR_FORMAT format)
  {
  	//disable mip-mapping
  	bool generateMipLevels = getTextureCreationFlag(ETCF_CREATE_MIP_MAPS);
  	setTextureCreationFlag(ETCF_CREATE_MIP_MAPS, false);
  
  	bool supportForFBO = (Feature.ColorAttachment > 0);
  
  	core::dimension2du destSize(size);
  
  	if (!supportForFBO)
  	{
  		destSize = core::dimension2d<u32>(core::min_(size.Width, ScreenSize.Width), core::min_(size.Height, ScreenSize.Height));
  		destSize = destSize.getOptimalSize((size == size.getOptimalSize()), false, false);
  	}
  
  	COpenGLTexture* renderTargetTexture = new COpenGLTexture(name, destSize, format, this);
  	addTexture(renderTargetTexture);
  	renderTargetTexture->drop();
  
  	//restore mip-mapping
  	setTextureCreationFlag(ETCF_CREATE_MIP_MAPS, generateMipLevels);
  
  	return renderTargetTexture;
  }
  
  
  //! Returns the maximum amount of primitives (mostly vertices) which
  //! the device is able to render with one drawIndexedTriangleList
  //! call.
  u32 COpenGLDriver::getMaximalPrimitiveCount() const
  {
  	return 0x7fffffff;
  }
  
  bool COpenGLDriver::setRenderTargetEx(IRenderTarget* target, u16 clearFlag, SColor clearColor, f32 clearDepth, u8 clearStencil)
  {
  	if (target && target->getDriverType() != EDT_OPENGL)
  	{
  		os::Printer::log("Fatal Error: Tried to set a render target not owned by this driver.", ELL_ERROR);
  		return false;
  	}
  
  	bool supportForFBO = (Feature.ColorAttachment > 0);
  
  	core::dimension2d<u32> destRenderTargetSize(0, 0);
  
  	if (target)
  	{
  		COpenGLRenderTarget* renderTarget = static_cast<COpenGLRenderTarget*>(target);
  
  		if (supportForFBO)
  		{
  			CacheHandler->setFBO(renderTarget->getBufferID());
  			renderTarget->update();
  		}
  
  		destRenderTargetSize = renderTarget->getSize();
  
  		CacheHandler->setViewport(0, 0, destRenderTargetSize.Width, destRenderTargetSize.Height);
  	}
  	else
  	{
  		if (supportForFBO)
  			CacheHandler->setFBO(0);
  		else
  		{
  			COpenGLRenderTarget* prevRenderTarget = static_cast<COpenGLRenderTarget*>(CurrentRenderTarget);
  			COpenGLTexture* renderTargetTexture = static_cast<COpenGLTexture*>(prevRenderTarget->getTexture());
  
  			if (renderTargetTexture)
  			{
  				const COpenGLTexture* prevTexture = CacheHandler->getTextureCache()[0];
  
  				CacheHandler->getTextureCache().set(0, renderTargetTexture);
  
  				const core::dimension2d<u32> size = renderTargetTexture->getSize();
  				glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, size.Width, size.Height);
  
  				CacheHandler->getTextureCache().set(0, prevTexture);
  			}
  		}
  
  		destRenderTargetSize = core::dimension2d<u32>(0, 0);
  
  		CacheHandler->setViewport(0, 0, ScreenSize.Width, ScreenSize.Height);
  	}
  
  	if (CurrentRenderTargetSize != destRenderTargetSize)
  	{
  		CurrentRenderTargetSize = destRenderTargetSize;
  
  		Transformation3DChanged = true;
  	}
  
  	CurrentRenderTarget = target;
  
  	if (!supportForFBO)
  	{
  		clearFlag |= ECBF_COLOR;
  		clearFlag |= ECBF_DEPTH;
  	}
  
  	clearBuffers(clearFlag, clearColor, clearDepth, clearStencil);
  
  	return true;
  }
  
  
  void COpenGLDriver::clearBuffers(u16 flag, SColor color, f32 depth, u8 stencil)
  {
  	GLbitfield mask = 0;
  	u8 colorMask = 0;
  	bool depthMask = false;
  
  	CacheHandler->getColorMask(colorMask);
  	CacheHandler->getDepthMask(depthMask);
  
  	if (flag & ECBF_COLOR)
  	{
  		CacheHandler->setColorMask(ECP_ALL);
  
  		const f32 inv = 1.0f / 255.0f;
  		glClearColor(color.getRed() * inv, color.getGreen() * inv,
  			color.getBlue() * inv, color.getAlpha() * inv);
  
  		mask |= GL_COLOR_BUFFER_BIT;
  	}
  
  	if (flag & ECBF_DEPTH)
  	{
  		CacheHandler->setDepthMask(true);
  		glClearDepth(depth);
  		mask |= GL_DEPTH_BUFFER_BIT;
  	}
  
  	if (flag & ECBF_STENCIL)
  	{
  		glClearStencil(stencil);
  		mask |= GL_STENCIL_BUFFER_BIT;
  	}
  
  	if (mask)
  		glClear(mask);
  
  	CacheHandler->setColorMask(colorMask);
  	CacheHandler->setDepthMask(depthMask);
  }
  
  
  //! Returns an image created from the last rendered frame.
  IImage* COpenGLDriver::createScreenShot(video::ECOLOR_FORMAT format, video::E_RENDER_TARGET target)
  {
  	if (target != video::ERT_FRAME_BUFFER)
  		return 0;
  
  	if (format==video::ECF_UNKNOWN)
  		format=getColorFormat();
  
  	if (IImage::isRenderTargetOnlyFormat(format) || IImage::isCompressedFormat(format) || IImage::isDepthFormat(format))
  		return 0;
  
  	// allows to read pixels in top-to-bottom order
  #ifdef GL_MESA_pack_invert
  	if (FeatureAvailable[IRR_MESA_pack_invert])
  		glPixelStorei(GL_PACK_INVERT_MESA, GL_TRUE);
  #endif
  
  	GLenum fmt;
  	GLenum type;
  
  	switch (format)
  	{
  	case ECF_A1R5G5B5:
  		fmt = GL_BGRA;
  		type = GL_UNSIGNED_SHORT_1_5_5_5_REV;
  		break;
  	case ECF_R5G6B5:
  		fmt = GL_RGB;
  		type = GL_UNSIGNED_SHORT_5_6_5;
  		break;
  	case ECF_R8G8B8:
  		fmt = GL_RGB;
  		type = GL_UNSIGNED_BYTE;
  		break;
  	case ECF_A8R8G8B8:
  		fmt = GL_BGRA;
  		if (Version > 101)
  			type = GL_UNSIGNED_INT_8_8_8_8_REV;
  		else
  			type = GL_UNSIGNED_BYTE;
  		break;
  	default:
  		fmt = GL_BGRA;
  		type = GL_UNSIGNED_BYTE;
  		break;
  	}
  	IImage* newImage = createImage(format, ScreenSize);
  
  	u8* pixels = 0;
  	if (newImage)
  		pixels = static_cast<u8*>(newImage->getData());
  	if (pixels)
  	{
  		GLenum tgt=GL_FRONT;
  		switch (target)
  		{
  		case video::ERT_FRAME_BUFFER:
  			break;
  		case video::ERT_STEREO_LEFT_BUFFER:
  			tgt=GL_FRONT_LEFT;
  			break;
  		case video::ERT_STEREO_RIGHT_BUFFER:
  			tgt=GL_FRONT_RIGHT;
  			break;
  		default:
  			tgt=GL_AUX0+(target-video::ERT_AUX_BUFFER0);
  			break;
  		}
  		glReadBuffer(tgt);
  		glReadPixels(0, 0, ScreenSize.Width, ScreenSize.Height, fmt, type, pixels);
  		testGLError(__LINE__);
  		glReadBuffer(GL_BACK);
  	}
  
  #ifdef GL_MESA_pack_invert
  	if (FeatureAvailable[IRR_MESA_pack_invert])
  		glPixelStorei(GL_PACK_INVERT_MESA, GL_FALSE);
  	else
  #endif
  	if (pixels)
  	{
  		// opengl images are horizontally flipped, so we have to fix that here.
  		const s32 pitch=newImage->getPitch();
  		u8* p2 = pixels + (ScreenSize.Height - 1) * pitch;
  		u8* tmpBuffer = new u8[pitch];
  		for (u32 i=0; i < ScreenSize.Height; i += 2)
  		{
  			memcpy(tmpBuffer, pixels, pitch);
  //			for (u32 j=0; j<pitch; ++j)
  //			{
  //				pixels[j]=(u8)(p2[j]*255.f);
  //			}
  			memcpy(pixels, p2, pitch);
  //			for (u32 j=0; j<pitch; ++j)
  //			{
  //				p2[j]=(u8)(tmpBuffer[j]*255.f);
  //			}
  			memcpy(p2, tmpBuffer, pitch);
  			pixels += pitch;
  			p2 -= pitch;
  		}
  		delete [] tmpBuffer;
  	}
  
  	if (newImage)
  	{
  		if (testGLError(__LINE__) || !pixels)
  		{
  			newImage->drop();
  			return 0;
  		}
  	}
  	return newImage;
  }
  
  //! Set/unset a clipping plane.
  bool COpenGLDriver::setClipPlane(u32 index, const core::plane3df& plane, bool enable)
  {
  	if (index >= MaxUserClipPlanes)
  		return false;
  
  	UserClipPlanes[index].Plane=plane;
  	enableClipPlane(index, enable);
  	return true;
  }
  
  
  void COpenGLDriver::uploadClipPlane(u32 index)
  {
  	// opengl needs an array of doubles for the plane equation
  	GLdouble clip_plane[4];
  	clip_plane[0] = UserClipPlanes[index].Plane.Normal.X;
  	clip_plane[1] = UserClipPlanes[index].Plane.Normal.Y;
  	clip_plane[2] = UserClipPlanes[index].Plane.Normal.Z;
  	clip_plane[3] = UserClipPlanes[index].Plane.D;
  	glClipPlane(GL_CLIP_PLANE0 + index, clip_plane);
  }
  
  
  //! Enable/disable a clipping plane.
  void COpenGLDriver::enableClipPlane(u32 index, bool enable)
  {
  	if (index >= MaxUserClipPlanes)
  		return;
  	if (enable)
  	{
  		if (!UserClipPlanes[index].Enabled)
  		{
  			uploadClipPlane(index);
  			glEnable(GL_CLIP_PLANE0 + index);
  		}
  	}
  	else
  		glDisable(GL_CLIP_PLANE0 + index);
  
  	UserClipPlanes[index].Enabled=enable;
  }
  
  
  core::dimension2du COpenGLDriver::getMaxTextureSize() const
  {
  	return core::dimension2du(MaxTextureSize, MaxTextureSize);
  }
  
  
  //! Convert E_PRIMITIVE_TYPE to OpenGL equivalent
  GLenum COpenGLDriver::primitiveTypeToGL(scene::E_PRIMITIVE_TYPE type) const
  {
  	switch (type)
  	{
  		case scene::EPT_POINTS:
  			return GL_POINTS;
  		case scene::EPT_LINE_STRIP:
  			return GL_LINE_STRIP;
  		case scene::EPT_LINE_LOOP:
  			return GL_LINE_LOOP;
  		case scene::EPT_LINES:
  			return GL_LINES;
  		case scene::EPT_TRIANGLE_STRIP:
  			return GL_TRIANGLE_STRIP;
  		case scene::EPT_TRIANGLE_FAN:
  			return GL_TRIANGLE_FAN;
  		case scene::EPT_TRIANGLES:
  			return GL_TRIANGLES;
  		case scene::EPT_QUAD_STRIP:
  			return GL_QUAD_STRIP;
  		case scene::EPT_QUADS:
  			return GL_QUADS;
  		case scene::EPT_POLYGON:
  			return GL_POLYGON;
  		case scene::EPT_POINT_SPRITES:
  #ifdef GL_ARB_point_sprite
  			return GL_POINT_SPRITE_ARB;
  #else
  			return GL_POINTS;
  #endif
  	}
  	return GL_TRIANGLES;
  }
  
  
  GLenum COpenGLDriver::getGLBlend(E_BLEND_FACTOR factor) const
  {
  	GLenum r = 0;
  	switch (factor)
  	{
  		case EBF_ZERO:			r = GL_ZERO; break;
  		case EBF_ONE:			r = GL_ONE; break;
  		case EBF_DST_COLOR:		r = GL_DST_COLOR; break;
  		case EBF_ONE_MINUS_DST_COLOR:	r = GL_ONE_MINUS_DST_COLOR; break;
  		case EBF_SRC_COLOR:		r = GL_SRC_COLOR; break;
  		case EBF_ONE_MINUS_SRC_COLOR:	r = GL_ONE_MINUS_SRC_COLOR; break;
  		case EBF_SRC_ALPHA:		r = GL_SRC_ALPHA; break;
  		case EBF_ONE_MINUS_SRC_ALPHA:	r = GL_ONE_MINUS_SRC_ALPHA; break;
  		case EBF_DST_ALPHA:		r = GL_DST_ALPHA; break;
  		case EBF_ONE_MINUS_DST_ALPHA:	r = GL_ONE_MINUS_DST_ALPHA; break;
  		case EBF_SRC_ALPHA_SATURATE:	r = GL_SRC_ALPHA_SATURATE; break;
  	}
  	return r;
  }
  
  GLenum COpenGLDriver::getZBufferBits() const
  {
  	GLenum bits = 0;
  	switch (Params.ZBufferBits)
  	{
  	case 16:
  		bits = GL_DEPTH_COMPONENT16;
  		break;
  	case 24:
  		bits = GL_DEPTH_COMPONENT24;
  		break;
  	case 32:
  		bits = GL_DEPTH_COMPONENT32;
  		break;
  	default:
  		bits = GL_DEPTH_COMPONENT;
  		break;
  	}
  	return bits;
  }
  
  bool COpenGLDriver::getColorFormatParameters(ECOLOR_FORMAT format, GLint& internalFormat, GLenum& pixelFormat,
  	GLenum& pixelType, void(**converter)(const void*, s32, void*)) const
  {
  	bool supported = false;
  	internalFormat = GL_RGBA;
  	pixelFormat = GL_RGBA;
  	pixelType = GL_UNSIGNED_BYTE;
  
  	switch (format)
  	{
  	case ECF_A1R5G5B5:
  		supported = true;
  		internalFormat = GL_RGBA;
  		pixelFormat = GL_BGRA_EXT;
  		pixelType = GL_UNSIGNED_SHORT_1_5_5_5_REV;
  		break;
  	case ECF_R5G6B5:
  		supported = true;
  		internalFormat = GL_RGB;
  		pixelFormat = GL_RGB;
  		pixelType = GL_UNSIGNED_SHORT_5_6_5;
  		break;
  	case ECF_R8G8B8:
  		supported = true;
  		internalFormat = GL_RGB;
  		pixelFormat = GL_BGR;
  		pixelType = GL_UNSIGNED_BYTE;
  		break;
  	case ECF_A8R8G8B8:
  		supported = true;
  		internalFormat = GL_RGBA;
  		pixelFormat = GL_BGRA_EXT;
  		if (Version > 101)
  			pixelType = GL_UNSIGNED_INT_8_8_8_8_REV;
  		break;
  	case ECF_DXT1:
  		supported = true;
  		internalFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
  		pixelFormat = GL_BGRA_EXT;
  		pixelType = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
  		break;
  	case ECF_DXT2:
  	case ECF_DXT3:
  		supported = true;
  		internalFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
  		pixelFormat = GL_BGRA_EXT;
  		pixelType = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
  		break;
  	case ECF_DXT4:
  	case ECF_DXT5:
  		supported = true;
  		internalFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
  		pixelFormat = GL_BGRA_EXT;
  		pixelType = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
  		break;
  	case ECF_D16:
  		supported = true;
  		internalFormat = GL_DEPTH_COMPONENT16;
  		pixelFormat = GL_DEPTH_COMPONENT;
  		pixelType = GL_UNSIGNED_SHORT;
  		break;
  	case ECF_D32:
  		supported = true;
  		internalFormat = GL_DEPTH_COMPONENT32;
  		pixelFormat = GL_DEPTH_COMPONENT;
  		pixelType = GL_UNSIGNED_INT;
  		break;
  	case ECF_D24S8:
  #ifdef GL_VERSION_3_0
  		if (Version >= 300)
  		{
  			supported = true;
  			internalFormat = GL_DEPTH_STENCIL;
  			pixelFormat = GL_DEPTH_STENCIL;
  			pixelType = GL_UNSIGNED_INT_24_8;
  		}
  		else
  #endif
  #ifdef GL_EXT_packed_depth_stencil
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_EXT_packed_depth_stencil))
  		{
  			supported = true;
  			internalFormat = GL_DEPTH_STENCIL_EXT;
  			pixelFormat = GL_DEPTH_STENCIL_EXT;
  			pixelType = GL_UNSIGNED_INT_24_8_EXT;
  		}
  #endif
  		break;
  	case ECF_R8:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_R8;
  			pixelFormat = GL_RED;
  			pixelType = GL_UNSIGNED_BYTE;
  		}
  		break;
  	case ECF_R8G8:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_RG8;
  			pixelFormat = GL_RG;
  			pixelType = GL_UNSIGNED_BYTE;
  		}
  		break;
  	case ECF_R16:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_R16;
  			pixelFormat = GL_RED;
  			pixelType = GL_UNSIGNED_SHORT;
  		}
  		break;
  	case ECF_R16G16:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_RG16;
  			pixelFormat = GL_RG;
  			pixelType = GL_UNSIGNED_SHORT;
  		}
  		break;
  	case ECF_R16F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_R16F;
  			pixelFormat = GL_RED;
  #ifdef GL_ARB_half_float_pixel
  			if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_half_float_pixel))
  				pixelType = GL_HALF_FLOAT_ARB;
  			else
  #endif
  				pixelType = GL_FLOAT;
  		}
  		break;
  	case ECF_G16R16F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_RG16F;
  			pixelFormat = GL_RG;
  #ifdef GL_ARB_half_float_pixel
  			if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_half_float_pixel))
  				pixelType = GL_HALF_FLOAT_ARB;
  			else
  #endif
  				pixelType = GL_FLOAT;
  		}
  		break;
  	case ECF_A16B16G16R16F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_float))
  		{
  			supported = true;
  			internalFormat = GL_RGBA16F_ARB;
  			pixelFormat = GL_RGBA;
  #ifdef GL_ARB_half_float_pixel
  			if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_half_float_pixel))
  				pixelType = GL_HALF_FLOAT_ARB;
  			else
  #endif
  				pixelType = GL_FLOAT;
  		}
  		break;
  	case ECF_R32F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_R32F;
  			pixelFormat = GL_RED;
  			pixelType = GL_FLOAT;
  		}
  		break;
  	case ECF_G32R32F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_rg))
  		{
  			supported = true;
  			internalFormat = GL_RG32F;
  			pixelFormat = GL_RG;
  			pixelType = GL_FLOAT;
  		}
  		break;
  	case ECF_A32B32G32R32F:
  		if (queryOpenGLFeature(COpenGLExtensionHandler::IRR_ARB_texture_float))
  		{
  			supported = true;
  			internalFormat = GL_RGBA32F_ARB;
  			pixelFormat = GL_RGBA;
  			pixelType = GL_FLOAT;
  		}
  		break;
  	default:
  		break;
  	}
  
  #if defined(GL_ARB_framebuffer_sRGB) || defined(GL_EXT_framebuffer_sRGB)
  	if (Params.HandleSRGB)
  	{
  		if (internalFormat == GL_RGBA)
  			internalFormat = GL_SRGB_ALPHA_EXT;
  		else if (internalFormat == GL_RGB)
  			internalFormat = GL_SRGB_EXT;
  	}
  #endif
  
  	return supported;
  }
  
  COpenGLDriver::E_OPENGL_FIXED_PIPELINE_STATE COpenGLDriver::getFixedPipelineState() const
  {
  	return FixedPipelineState;
  }
  
  void COpenGLDriver::setFixedPipelineState(COpenGLDriver::E_OPENGL_FIXED_PIPELINE_STATE state)
  {
  	FixedPipelineState = state;
  }
  
  const SMaterial& COpenGLDriver::getCurrentMaterial() const
  {
  	return Material;
  }
  
  COpenGLCacheHandler* COpenGLDriver::getCacheHandler() const
  {
  	return CacheHandler;
  }
  
  
  } // end namespace
  } // end namespace
  
  #endif // _IRR_COMPILE_WITH_OPENGL_
  
  namespace irr
  {
  namespace video
  {
  
  #if defined(_IRR_COMPILE_WITH_WINDOWS_DEVICE_) || defined(_IRR_COMPILE_WITH_X11_DEVICE_) || defined(_IRR_COMPILE_WITH_OSX_DEVICE_)
  	IVideoDriver* createOpenGLDriver(const SIrrlichtCreationParameters& params, io::IFileSystem* io, IContextManager* contextManager)
  	{
  #ifdef _IRR_COMPILE_WITH_OPENGL_
  		COpenGLDriver* ogl = new COpenGLDriver(params, io, contextManager);
  
  		if (!ogl->initDriver())
  		{
  			ogl->drop();
  			ogl = 0;
  		}
  
  		return ogl;
  #else
  		return 0;
  #endif
  	}
  #endif
  
  // -----------------------------------
  // SDL VERSION
  // -----------------------------------
  #ifdef _IRR_COMPILE_WITH_SDL_DEVICE_
  IVideoDriver* createOpenGLDriver(const SIrrlichtCreationParameters& params,
  		io::IFileSystem* io, CIrrDeviceSDL* device)
  {
  #ifdef _IRR_COMPILE_WITH_OPENGL_
  	return new COpenGLDriver(params, io, device);
  #else
  	return 0;
  #endif //  _IRR_COMPILE_WITH_OPENGL_
  }
  #endif // _IRR_COMPILE_WITH_SDL_DEVICE_
  
  } // end namespace
  } // end namespace
  
  
  