text: /*
  -----------------------------------------------------------------------------
  This source file is part of OGRE
      (Object-oriented Graphics Rendering Engine)
  For the latest info, see http://www.ogre3d.org
  
  Copyright (c) 2000-2014 Torus Knot Software Ltd
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
  -----------------------------------------------------------------------------
  */
  #ifndef __GLRenderSystem_H__
  #define __GLRenderSystem_H__
  
  #include "OgreGLPrerequisites.h"
  #include "OgrePlatform.h"
  #include "OgreRenderSystem.h"
  #include "OgreGLHardwareBufferManager.h"
  #include "OgreGLGpuProgramManager.h"
  #include "OgreVector4.h"
  
  #include "OgreGLRenderSystemCommon.h"
  #include "OgreGLStateCacheManager.h"
  
  namespace Ogre {
      /** \addtogroup RenderSystems RenderSystems
      *  @{
      */
      /** \defgroup GL GL
      * Implementation of GL as a rendering system.
      *  @{
      */
  
      namespace GLSL {
          class GLSLProgramFactory;
      }
  
      /**
        Implementation of GL as a rendering system.
       */
      class _OgreGLExport GLRenderSystem : public GLRenderSystemCommon
      {
      private:
          /// Rendering loop control
          bool mStopRendering;
  
          /// View matrix to set world against
          Matrix4 mViewMatrix;
          Matrix4 mWorldMatrix;
          Matrix4 mTextureMatrix;
  
          /// Last min & mip filtering options, so we can combine them
          FilterOptions mMinFilter;
          FilterOptions mMipFilter;
  
          /// What texture coord set each texture unit is using
          size_t mTextureCoordIndex[OGRE_MAX_TEXTURE_LAYERS];
  
          /// Holds texture type settings for every stage
          GLenum mTextureTypes[OGRE_MAX_TEXTURE_LAYERS];
  
          /// Number of fixed-function texture units
          unsigned short mFixedFunctionTextureUnits;
  
          void setGLLight(size_t index, bool lt);
          void makeGLMatrix(GLfloat gl_matrix[16], const Matrix4& m);
   
          GLint getBlendMode(SceneBlendFactor ogreBlend) const;
          GLint getTextureAddressingMode(TextureAddressingMode tam) const;
                  void initialiseContext(RenderWindow* primary);
  
          /// Store last colour write state
          bool mColourWrite[4];
          /// Store last stencil mask state
          uint32 mStencilWriteMask;
          /// Store last depth write state
          bool mDepthWrite;
          /// Store last scissor enable state
          bool mScissorsEnabled;
  
          /// Store scissor box
          int mScissorBox[4];
  
          GLint convertCompareFunction(CompareFunction func) const;
          GLint convertStencilOp(StencilOperation op, bool invert = false) const;
  
          bool mUseAutoTextureMatrix;
          GLfloat mAutoTextureMatrix[16];
  
          /// Check if the GL system has already been initialised
          bool mGLInitialised;
  
          HardwareBufferManager* mHardwareBufferManager;
          GLGpuProgramManager* mGpuProgramManager;
          GLSL::GLSLProgramFactory* mGLSLProgramFactory;
  
          unsigned short mCurrentLights;
  
          GLGpuProgram* mCurrentVertexProgram;
          GLGpuProgram* mCurrentFragmentProgram;
          GLGpuProgram* mCurrentGeometryProgram;
  
          // statecaches are per context
          GLStateCacheManager* mStateCacheManager;
  
          ushort mActiveTextureUnit;
          ushort mMaxBuiltInTextureAttribIndex;
  
          // local data members of _render that were moved here to improve performance
          // (save allocations)
          std::vector<GLuint> mRenderAttribsBound;
          std::vector<GLuint> mRenderInstanceAttribsBound;
  
  #if OGRE_NO_QUAD_BUFFER_STEREO == 0
  		/// @copydoc RenderSystem::setDrawBuffer
  		virtual bool setDrawBuffer(ColourBufferType colourBuffer);
  #endif
  
      protected:
          void setClipPlanesImpl(const PlaneList& clipPlanes);
          void bindVertexElementToGpu(const VertexElement& elem,
                                      const HardwareVertexBufferSharedPtr& vertexBuffer,
                                      const size_t vertexStart);
  
          /** Initialises GL extensions, must be done AFTER the GL context has been
              established.
          */
          void initialiseExtensions();
      public:
          // Default constructor / destructor
          GLRenderSystem();
          ~GLRenderSystem();
  
          // ----------------------------------
          // Overridden RenderSystem functions
          // ----------------------------------
  
          const GpuProgramParametersPtr& getFixedFunctionParams(TrackVertexColourType tracking, FogMode fog);
  
          void applyFixedFunctionParams(const GpuProgramParametersPtr& params, uint16 variabilityMask);
  
          const String& getName(void) const;
  
          void _initialise() override;
  
          virtual RenderSystemCapabilities* createRenderSystemCapabilities() const;
  
          void initialiseFromRenderSystemCapabilities(RenderSystemCapabilities* caps, RenderTarget* primary);
  
          void shutdown(void);
  
          void setShadingType(ShadeOptions so);
  
          void setLightingEnabled(bool enabled);
          
          /// @copydoc RenderSystem::_createRenderWindow
          RenderWindow* _createRenderWindow(const String &name, unsigned int width, unsigned int height, 
                                            bool fullScreen, const NameValuePairList *miscParams = 0);
  
          /// @copydoc RenderSystem::_createRenderWindows
          bool _createRenderWindows(const RenderWindowDescriptionList& renderWindowDescriptions, 
                                    RenderWindowList& createdWindows);
  
          /// @copydoc RenderSystem::_createDepthBufferFor
          DepthBuffer* _createDepthBufferFor( RenderTarget *renderTarget );
          
          /// @copydoc RenderSystem::createMultiRenderTarget
          virtual MultiRenderTarget * createMultiRenderTarget(const String & name); 
          
  
          void destroyRenderWindow(const String& name);
  
          void setNormaliseNormals(bool normalise);
  
          // -----------------------------
          // Low-level overridden members
          // -----------------------------
  
          void _useLights(unsigned short limit);
  
          void setWorldMatrix(const Matrix4 &m);
  
          void setViewMatrix(const Matrix4 &m);
  
          void setProjectionMatrix(const Matrix4 &m);
  
          void _setSurfaceTracking(TrackVertexColourType tracking);
  
          void _setPointParameters(bool attenuationEnabled, Real minSize, Real maxSize);
  
          void _setLineWidth(float width);
  
          void _setPointSpritesEnabled(bool enabled);
  
          void _setTexture(size_t unit, bool enabled, const TexturePtr &tex);
  
          void _setSampler(size_t unit, Sampler& sampler);
  
          void _setTextureCoordSet(size_t stage, size_t index);
  
          void _setTextureCoordCalculation(size_t stage, TexCoordCalcMethod m, 
              const Frustum* frustum = 0);
  
          void _setTextureBlendMode(size_t stage, const LayerBlendModeEx& bm);
  
          void _setTextureAddressingMode(size_t stage, const Sampler::UVWAddressingMode& uvw);
  
          void _setTextureMatrix(size_t stage, const Matrix4& xform);
  
          void _setSeparateSceneBlending(SceneBlendFactor sourceFactor, SceneBlendFactor destFactor, SceneBlendFactor sourceFactorAlpha, SceneBlendFactor destFactorAlpha, SceneBlendOperation op, SceneBlendOperation alphaOp );
  
          void _setAlphaRejectSettings(CompareFunction func, unsigned char value, bool alphaToCoverage);
  
          void _setViewport(Viewport *vp);
  
          void _beginFrame(void);
  
          void _endFrame(void);
  
          void _setCullingMode(CullingMode mode);
  
          void _setDepthBufferParams(bool depthTest = true, bool depthWrite = true, CompareFunction depthFunction = CMPF_LESS_EQUAL);
  
          void _setDepthBufferCheckEnabled(bool enabled = true);
  
          void _setDepthBufferWriteEnabled(bool enabled = true);
  
          void _setDepthBufferFunction(CompareFunction func = CMPF_LESS_EQUAL);
  
          void _setDepthBias(float constantBias, float slopeScaleBias);
  
          void _setColourBufferWriteEnabled(bool red, bool green, bool blue, bool alpha);
  
          void _setFog(FogMode mode);
  
          void setClipPlane (ushort index, Real A, Real B, Real C, Real D);
  
          void enableClipPlane (ushort index, bool enable);
  
          void _setPolygonMode(PolygonMode level);
  
          void setStencilCheckEnabled(bool enabled);
          /** See
            RenderSystem.
           */
          void setStencilBufferParams(CompareFunction func = CMPF_ALWAYS_PASS, 
              uint32 refValue = 0, uint32 compareMask = 0xFFFFFFFF, uint32 writeMask = 0xFFFFFFFF,
              StencilOperation stencilFailOp = SOP_KEEP, 
              StencilOperation depthFailOp = SOP_KEEP,
              StencilOperation passOp = SOP_KEEP, 
              bool twoSidedOperation = false,
              bool readBackAsTexture = false);
  
          void _setTextureUnitFiltering(size_t unit, FilterType ftype, FilterOptions filter);
  
          void _render(const RenderOperation& op);
  
          void bindGpuProgram(GpuProgram* prg);
  
          void unbindGpuProgram(GpuProgramType gptype);
  
          void bindGpuProgramParameters(GpuProgramType gptype, 
                                        const GpuProgramParametersPtr& params, uint16 variabilityMask);
  
          void setScissorTest(bool enabled, size_t left = 0, size_t top = 0, size_t right = 800, size_t bottom = 600) ;
          void clearFrameBuffer(unsigned int buffers, 
                                const ColourValue& colour = ColourValue::Black, 
                                Real depth = 1.0f, unsigned short stencil = 0);
          HardwareOcclusionQuery* createHardwareOcclusionQuery(void);
  
          // ----------------------------------
          // GLRenderSystem specific members
          // ----------------------------------
          void _oneTimeContextInitialization();
          /** Switch GL context, dealing with involved internal cached states too
          */
          void _switchContext(GLContext *context);
          /**
           * Set current render target to target, enabling its GL context if needed
           */
          void _setRenderTarget(RenderTarget *target);
          /** Unregister a render target->context mapping. If the context of target 
              is the current context, change the context to the main context so it
              can be destroyed safely. 
              
              @note This is automatically called by the destructor of 
              GLContext.
           */
          void _unregisterContext(GLContext *context);
  
          GLStateCacheManager * _getStateCacheManager() { return mStateCacheManager; }
  
          /// @copydoc RenderSystem::getDisplayMonitorCount
          unsigned int getDisplayMonitorCount() const;
          
          /// @copydoc RenderSystem::beginProfileEvent
          virtual void beginProfileEvent( const String &eventName );
  
          /// @copydoc RenderSystem::endProfileEvent
          virtual void endProfileEvent( void );
  
          /// @copydoc RenderSystem::markProfileEvent
          virtual void markProfileEvent( const String &eventName );
  
          /** @copydoc RenderTarget::copyContentsToMemory */
          void _copyContentsToMemory(Viewport* vp, const Box& src, const PixelBox &dst, RenderWindow::FrameBuffer buffer);
      };
      /** @} */
      /** @} */
  }
  #endif
  
  