text: // Copyright (C) 2013 Patryk Nadrowski
  // Heavily based on the OpenGL driver implemented by Nikolaus Gebhardt
  // OpenGL ES driver implemented by Christian Stehno and first OpenGL ES 2.0
  // driver implemented by Amundis.
  // This file is part of the "Irrlicht Engine".
  // For conditions of distribution and use, see copyright notice in Irrlicht.h
  
  #ifndef __C_OGLES2_DRIVER_H_INCLUDED__
  #define __C_OGLES2_DRIVER_H_INCLUDED__
  
  #include "IrrCompileConfig.h"
  
  #if defined(_IRR_WINDOWS_API_)
  // include windows headers for HWND
  #ifndef WIN32_LEAN_AND_MEAN
  #define WIN32_LEAN_AND_MEAN
  #endif
  #include <windows.h>
  #elif defined(_IRR_COMPILE_WITH_OSX_DEVICE_)
  #include "MacOSX/CIrrDeviceMacOSX.h"
  #elif defined(_IRR_COMPILE_WITH_IPHONE_DEVICE_)
  #include "iOS/CIrrDeviceiOS.h"
  #endif
  
  #include "SIrrCreationParameters.h"
  
  #ifdef _IRR_COMPILE_WITH_OGLES2_
  
  #include "CNullDriver.h"
  #include "IMaterialRendererServices.h"
  #include "EDriverFeatures.h"
  #include "fast_atof.h"
  
  #include "COGLES2ExtensionHandler.h"
  #ifdef _MSC_VER
  #pragma comment(lib, "libGLESv2.lib")
  #endif
  
  namespace irr
  {
  namespace video
  {
  	class COGLES2CallBridge;
  	class COGLES2Texture;
  	class COGLES2FixedPipelineRenderer;
  	class COGLES2Renderer2D;
  	class COGLES2NormalMapRenderer;
  	class COGLES2ParallaxMapRenderer;
  	class IContextManager;
  
  	class COGLES2Driver : public CNullDriver, public IMaterialRendererServices, public COGLES2ExtensionHandler
  	{
  		friend class COGLES2CallBridge;
  		friend class COGLES2Texture;
  
  	public:
  		//! constructor
  		COGLES2Driver(const SIrrlichtCreationParameters& params,
  				io::IFileSystem* io
  #if defined(_IRR_COMPILE_WITH_X11_DEVICE_) || defined(_IRR_WINDOWS_API_) || defined(_IRR_COMPILE_WITH_ANDROID_DEVICE_) || defined(_IRR_COMPILE_WITH_SDL2_DEVICE_)
  		, IContextManager* contextManager
  #elif defined(_IRR_COMPILE_WITH_IPHONE_DEVICE_)
  		, CIrrDeviceIPhone* device
  #endif
  		);
  
  		//! destructor
  		virtual ~COGLES2Driver();
  
  		//! clears the zbuffer
  		virtual bool beginScene(bool backBuffer=true, bool zBuffer=true,
  					SColor color=SColor(255, 0, 0, 0),
  					const SExposedVideoData& videoData=SExposedVideoData(),
  					core::rect<s32>* sourceRect=0);
  
  		//! presents the rendered scene on the screen, returns false if failed
  		virtual bool endScene();
  
  		//! sets transformation
  		virtual void setTransform(E_TRANSFORMATION_STATE state, const core::matrix4& mat);
  
  		struct SHWBufferLink_opengl : public SHWBufferLink
  		{
  			SHWBufferLink_opengl(const scene::IMeshBuffer *meshBuffer): SHWBufferLink(meshBuffer), vbo_verticesID(0), vbo_indicesID(0) {}
  
  			u32 vbo_verticesID; //tmp
  			u32 vbo_indicesID; //tmp
  
  			u32 vbo_verticesSize; //tmp
  			u32 vbo_indicesSize; //tmp
  		};
  
  		bool updateVertexHardwareBuffer(SHWBufferLink_opengl *HWBuffer);
  		bool updateIndexHardwareBuffer(SHWBufferLink_opengl *HWBuffer);
  
  		//! updates hardware buffer if needed
  		virtual bool updateHardwareBuffer(SHWBufferLink *HWBuffer);
  
  		//! Create hardware buffer from mesh
  		virtual SHWBufferLink *createHardwareBuffer(const scene::IMeshBuffer* mb);
  
  		//! Delete hardware buffer (only some drivers can)
  		virtual void deleteHardwareBuffer(SHWBufferLink *HWBuffer);
  
  		//! Draw hardware buffer
  		virtual void drawHardwareBuffer(SHWBufferLink *HWBuffer);
  
  		//! draws a vertex primitive list
  		virtual void drawVertexPrimitiveList(const void* vertices, u32 vertexCount,
  				const void* indexList, u32 primitiveCount,
  				E_VERTEX_TYPE vType, scene::E_PRIMITIVE_TYPE pType, E_INDEX_TYPE iType);
  
  		void drawVertexPrimitiveList2d3d(const void* vertices, u32 vertexCount,
  				const void* indexList, u32 primitiveCount,
  				E_VERTEX_TYPE vType, scene::E_PRIMITIVE_TYPE pType,
  				E_INDEX_TYPE iType = EIT_16BIT, bool threed = true);
  
  		//! queries the features of the driver, returns true if feature is available
  		virtual bool queryFeature(E_VIDEO_DRIVER_FEATURE feature) const
  		{
  			return FeatureEnabled[feature] && COGLES2ExtensionHandler::queryFeature(feature);
  		}
  
  		//! Sets a material.
  		virtual void setMaterial(const SMaterial& material);
  
  		//! draws an 2d image, using a color (if color is other then Color(255,255,255,255)) and the alpha channel of the texture if wanted.
  		virtual void draw2DImage(const video::ITexture* texture,
  				const core::position2d<s32>& destPos,
  				const core::rect<s32>& sourceRect, const core::rect<s32>* clipRect = 0,
  				SColor color = SColor(255, 255, 255, 255), bool useAlphaChannelOfTexture = false);
  
  		//! draws a set of 2d images
  		virtual void draw2DImageBatch(const video::ITexture* texture,
  				const core::position2d<s32>& pos,
  				const core::array<core::rect<s32> >& sourceRects,
  				const core::array<s32>& indices, s32 kerningWidth = 0,
  				const core::rect<s32>* clipRect = 0,
  				SColor color = SColor(255, 255, 255, 255),
  				bool useAlphaChannelOfTexture = false);
  
  		//! Draws a part of the texture into the rectangle.
  		virtual void draw2DImage(const video::ITexture* texture, const core::rect<s32>& destRect,
  				const core::rect<s32>& sourceRect, const core::rect<s32>* clipRect = 0,
  				const video::SColor* const colors = 0, bool useAlphaChannelOfTexture = false);
  
  		void 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);
  
  		//! draw an 2d rectangle
  		virtual void draw2DRectangle(SColor color, const core::rect<s32>& pos,
  				const core::rect<s32>* clip = 0);
  
  		//!Draws an 2d rectangle with a gradient.
  		virtual void draw2DRectangle(const core::rect<s32>& pos,
  				SColor colorLeftUp, SColor colorRightUp, SColor colorLeftDown, SColor colorRightDown,
  				const core::rect<s32>* clip = 0);
  
  		//! Draws a 2d line.
  		virtual void draw2DLine(const core::position2d<s32>& start,
  				const core::position2d<s32>& end,
  				SColor color = SColor(255, 255, 255, 255));
  
  		//! Draws a single pixel
  		virtual void drawPixel(u32 x, u32 y, const SColor & color);
  
  		//! Draws a 3d line.
  		virtual void draw3DLine(const core::vector3df& start,
  				const core::vector3df& end,
  				SColor color = SColor(255, 255, 255, 255));
  
  		//! Draws a pixel
  //			virtual void drawPixel(u32 x, u32 y, const SColor & color);
  
  		//! Returns the name of the video driver.
  		virtual const wchar_t* getName() const;
  
  		//! deletes all dynamic lights there are
  		virtual void deleteAllDynamicLights();
  
  		//! adds a dynamic light
  		virtual s32 addDynamicLight(const SLight& light);
  
  		//! 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 */
  		virtual void turnLightOn(s32 lightIndex, bool turnOn);
  
  		//! returns the maximal amount of dynamic lights the device can handle
  		virtual u32 getMaximalDynamicLightAmount() const;
  
  		//! Sets the dynamic ambient light color.
  		virtual void setAmbientLight(const SColorf& color);
  
  		//! return the dynamic ambient light color.
  		const SColorf& getAmbientLight() const;
  
  		//! Returns the maximum texture size supported.
  		virtual core::dimension2du getMaxTextureSize() const;
  
  		//! Draws a shadow volume into the stencil buffer.
  		virtual void drawStencilShadowVolume(const core::vector3df* triangles, s32 count, bool zfail);
  
  		//! Fills the stencil shadow with color.
  		virtual void drawStencilShadow(bool clearStencilBuffer = false,
  				video::SColor leftUpEdge = video::SColor(0, 0, 0, 0),
  				video::SColor rightUpEdge = video::SColor(0, 0, 0, 0),
  				video::SColor leftDownEdge = video::SColor(0, 0, 0, 0),
  				video::SColor rightDownEdge = video::SColor(0, 0, 0, 0));
  
  		//! sets a viewport
  		virtual void setViewPort(const core::rect<s32>& area);
  
  		//! Only used internally by the engine
  		virtual void OnResize(const core::dimension2d<u32>& size);
  
  		//! Returns type of video driver
  		virtual E_DRIVER_TYPE getDriverType() const;
  
  		//! get color format of the current color buffer
  		virtual ECOLOR_FORMAT getColorFormat() const;
  
  		//! Returns the transformation set by setTransform
  		virtual const core::matrix4& getTransform(E_TRANSFORMATION_STATE state) const;
  
  		//! Can be called by an IMaterialRenderer to make its work easier.
  		virtual void setBasicRenderStates(const SMaterial& material, const SMaterial& lastmaterial, bool resetAllRenderstates);
  
  		//! Compare in SMaterial doesn't check texture parameters, so we should call this on each OnRender call.
  		virtual void setTextureRenderStates(const SMaterial& material, bool resetAllRenderstates);
  
  		//! Get a vertex shader constant index.
  		virtual s32 getVertexShaderConstantID(const c8* name);
  
  		//! Get a pixel shader constant index.
  		virtual s32 getPixelShaderConstantID(const c8* name);
  
  		//! Sets a vertex shader constant.
  		virtual void setVertexShaderConstant(const f32* data, s32 startRegister, s32 constantAmount = 1);
  
  		//! Sets a pixel shader constant.
  		virtual void setPixelShaderConstant(const f32* data, s32 startRegister, s32 constantAmount = 1);
  
  		//! Sets a constant for the vertex shader based on an index.
  		virtual bool setVertexShaderConstant(s32 index, const f32* floats, int count);
  
  		//! Int interface for the above.
  		virtual bool setVertexShaderConstant(s32 index, const s32* ints, int count);
  
  		//! Sets a constant for the pixel shader based on an index.
  		virtual bool setPixelShaderConstant(s32 index, const f32* floats, int count);
  
  		//! Int interface for the above.
  		virtual bool setPixelShaderConstant(s32 index, const s32* ints, int count);
  
  		//! sets the current Texture
  		bool setActiveTexture(u32 stage, const video::ITexture* texture);
  
  		//! check if active texture is not equal null.
  		bool isActiveTexture(u32 stage);
  
  		//! disables all textures beginning with fromStage.
  		bool disableTextures(u32 fromStage = 0);
  
  		//! Adds a new material renderer to the VideoDriver
  		virtual s32 addShaderMaterial(const c8* vertexShaderProgram, const c8* pixelShaderProgram,
  				IShaderConstantSetCallBack* callback, E_MATERIAL_TYPE baseMaterial, s32 userData);
  
  		//! Adds a new material renderer to the VideoDriver
  		virtual s32 addHighLevelShaderMaterial(
  				const c8* vertexShaderProgram,
  				const c8* vertexShaderEntryPointName = 0,
  				E_VERTEX_SHADER_TYPE vsCompileTarget = EVST_VS_1_1,
  				const c8* pixelShaderProgram = 0,
  				const c8* pixelShaderEntryPointName = 0,
  				E_PIXEL_SHADER_TYPE psCompileTarget = EPST_PS_1_1,
  				const c8* geometryShaderProgram = 0,
  				const c8* geometryShaderEntryPointName = "main",
  				E_GEOMETRY_SHADER_TYPE gsCompileTarget = EGST_GS_4_0,
  				scene::E_PRIMITIVE_TYPE inType = scene::EPT_TRIANGLES,
  				scene::E_PRIMITIVE_TYPE outType = scene::EPT_TRIANGLE_STRIP,
  				u32 verticesOut = 0,
  				IShaderConstantSetCallBack* callback = 0,
  				E_MATERIAL_TYPE baseMaterial = video::EMT_SOLID,
  				s32 userData=0,
  				E_GPU_SHADING_LANGUAGE shadingLang = EGSL_DEFAULT);
  
  		//! Returns pointer to the IGPUProgrammingServices interface.
  		virtual IGPUProgrammingServices* getGPUProgrammingServices();
  
  		//! Returns a pointer to the IVideoDriver interface.
  		virtual IVideoDriver* getVideoDriver();
  
  		//! Returns the maximum amount of primitives
  		virtual u32 getMaximalPrimitiveCount() const;
  
  		virtual ITexture* addRenderTargetTexture(const core::dimension2d<u32>& size,
  				const io::path& name, const ECOLOR_FORMAT format = ECF_UNKNOWN);
  
  		virtual bool setRenderTarget(video::ITexture* texture, bool clearBackBuffer,
  				bool clearZBuffer, SColor color);
  
  		//! set or reset special render targets
  //			virtual bool setRenderTarget(video::E_RENDER_TARGET target, bool clearTarget,
  //					bool clearZBuffer, SColor color);
  
  		//! Sets multiple render targets
  //			virtual bool setRenderTarget(const core::array<video::IRenderTarget>& texture,
  //					bool clearBackBuffer=true, bool clearZBuffer=true, SColor color=SColor(0,0,0,0));
  
  		//! Clears the ZBuffer.
  		virtual void clearZBuffer();
  
  		//! Returns an image created from the last rendered frame.
  		virtual IImage* createScreenShot(video::ECOLOR_FORMAT format=video::ECF_UNKNOWN, video::E_RENDER_TARGET target=video::ERT_FRAME_BUFFER);
  
  		//! checks if an OpenGL error has happend and prints it
  		bool testGLError();
  
  		//! checks if an OGLES1 error has happend and prints it
  		bool testEGLError();
  
  		//! Set/unset a clipping plane.
  		virtual bool setClipPlane(u32 index, const core::plane3df& plane, bool enable = false);
  
  		//! returns the current amount of user clip planes set.
  		u32 getClipPlaneCount() const;
  
  		//! returns the 0 indexed Plane
  		const core::plane3df& getClipPlane(u32 index) const;
  
  		//! Enable/disable a clipping plane.
  		virtual void enableClipPlane(u32 index, bool enable);
  
  		//! Returns the graphics card vendor name.
  		virtual core::stringc getVendorInfo()
  		{
  			return vendorName;
  		};
  
  		ITexture* createDepthTexture(ITexture* texture, bool shared = true);
  		void removeDepthTexture(ITexture* texture);
  
  		void deleteFramebuffers(s32 n, const u32 *framebuffers);
  		void deleteRenderbuffers(s32 n, const u32 *renderbuffers);
  
  		// returns the current size of the screen or rendertarget
  		virtual const core::dimension2d<u32>& getCurrentRenderTargetSize() const;
  
  		//! Convert E_BLEND_FACTOR to OpenGL equivalent
  		GLenum getGLBlend(E_BLEND_FACTOR factor) const;
  
  		//! Get ZBuffer bits.
  		GLenum getZBufferBits() const;
  
  		//! Get current material.
  		const SMaterial& getCurrentMaterial() const;
  
  		//! Get bridge calls.
  		COGLES2CallBridge* getBridgeCalls() const;
  
  	private:
  		// Bridge calls.
  		COGLES2CallBridge* BridgeCalls;
  
  		void uploadClipPlane(u32 index);
  
  		//! inits the opengl-es driver
  		bool genericDriverInit(const core::dimension2d<u32>& screenSize, bool stencilBuffer);
  
  		//! returns a device dependent texture from a software surface (IImage)
  		virtual ITexture* createDeviceDependentTexture(IImage* surface, const io::path& name, void* mipmapData);
  
  		//! returns a device dependent texture from a software surface (IImage)
  		virtual ITexture* createDeviceDependentTextureCube(const io::path& name, IImage* posXImage, IImage* negXImage,
  			IImage* posYImage, IImage* negYImage, IImage* posZImage, IImage* negZImage);
  
  		//! creates a transposed matrix in supplied GLfloat array to pass to OGLES1
  		inline void createGLMatrix(float gl_matrix[16], const core::matrix4& m);
  
  		inline void createGLTextureMatrix(float gl_matrix[16], const core::matrix4& m);
  
  		//! Map Irrlicht wrap mode to OpenGL enum
  		GLint getTextureWrapMode(u8 clamp) const;
  
  		//! sets the needed renderstates
  		void setRenderStates3DMode();
  
  		//! sets the needed renderstates
  		void setRenderStates2DMode(bool alpha, bool texture, bool alphaChannel);
  
  		void createMaterialRenderers();
  
  		core::stringw Name;
  		core::matrix4 Matrices[ETS_COUNT];
  
  		//! enumeration for rendering modes such as 2d and 3d for minizing the switching of renderStates.
  		enum E_RENDER_MODE
  		{
  			ERM_NONE = 0, // no render state has been set yet.
  			ERM_2D, // 2d drawing rendermode
  			ERM_3D // 3d rendering mode
  		};
  
  		E_RENDER_MODE CurrentRenderMode;
  		//! bool to make all renderstates reset if set to true.
  		bool ResetRenderStates;
  		bool Transformation3DChanged;
  		u8 AntiAlias;
  
  		SMaterial Material, LastMaterial;
  		COGLES2Texture* RenderTargetTexture;
  		const ITexture* CurrentTexture[MATERIAL_MAX_TEXTURES];
  		core::array<ITexture*> DepthTextures;
  
  		struct SUserClipPlane
  		{
  			core::plane3df Plane;
  			bool Enabled;
  		};
  
  		core::array<SUserClipPlane> UserClipPlane;
  
  		core::dimension2d<u32> CurrentRendertargetSize;
  
  		core::stringc vendorName;
  
  		core::matrix4 TextureFlipMatrix;
  
  		//! Color buffer format
  		ECOLOR_FORMAT ColorFormat;
  
  		//! All the lights that have been requested; a hardware limited
  		//! number of them will be used at once.
  		struct RequestedLight
  		{
  			RequestedLight(SLight const & lightData)
  					: LightData(lightData), DesireToBeOn(true) { }
  
  			SLight LightData;
  			bool DesireToBeOn;
  		};
  
  		core::array<RequestedLight> RequestedLights;
  		SColorf AmbientLight;
  
  		COGLES2Renderer2D* MaterialRenderer2D;
  
  #if defined(_IRR_COMPILE_WITH_IPHONE_DEVICE_)
  		CIrrDeviceIPhone* Device;
  		GLuint ViewFramebuffer;
  		GLuint ViewRenderbuffer;
  		GLuint ViewDepthRenderbuffer;
  #elif defined(_IRR_COMPILE_WITH_X11_DEVICE_) || defined(_IRR_WINDOWS_API_) || defined(_IRR_COMPILE_WITH_ANDROID_DEVICE_) || defined(_IRR_COMPILE_WITH_SDL2_DEVICE_)
  		IContextManager* ContextManager;
  #endif
  	};
  
  	//! This bridge between Irlicht pseudo OpenGL calls
  	//! and true OpenGL calls.
  
  	class COGLES2CallBridge
  	{
  	public:
  		COGLES2CallBridge(COGLES2Driver* driver);
  
  		// Blending calls.
  
  		void setBlendFunc(GLenum source, GLenum destination);
  
  		void setBlend(bool enable);
  
  		// Cull face calls.
  
  		void setCullFaceFunc(GLenum mode);
  
  		void setCullFace(bool enable);
  
  		// Depth calls.
  
  		void setDepthFunc(GLenum mode);
  
  		void setDepthMask(bool enable);
  
  		void setDepthTest(bool enable);
  
  		// Program calls.
  
  		void setProgram(GLuint program);
  
  		// Texture calls.
  
  		void setActiveTexture(GLenum texture);
  
  		void getTexture(u32 stage, GLenum& type);
  
  		void setTexture(u32 stage, GLenum type);
  
  		// Viewport calls.
  
  		void setViewport(const core::rect<s32>& viewport);
  
  	private:
  		COGLES2Driver* Driver;
  
  		GLenum BlendSource;
  		GLenum BlendDestination;
  		bool Blend;
  
  		GLenum CullFaceMode;
  		bool CullFace;
  
  		GLenum DepthFunc;
  		bool DepthMask;
  		bool DepthTest;
  
  		GLuint Program;
  
  		GLenum ActiveTexture;
  
  		const ITexture* Texture[MATERIAL_MAX_TEXTURES];
  		GLenum TextureType[MATERIAL_MAX_TEXTURES];
  
  		core::rect<s32> Viewport;
  	};
  
  } // end namespace video
  } // end namespace irr
  
  #endif // _IRR_COMPILE_WITH_OPENGL_
  
  #endif
  