/*
-----------------------------------------------------------------------------
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"


namespace Ogre {


    namespace GLSL {
        class GLSLProgramFactory;
    }

    class GLStateCacheManager;

	/**
      Implementation of GL as a rendering system.
     */
    class _OgreGLExport GLRenderSystem : public RenderSystem
    {
    private:
        /// Rendering loop control
        bool mStopRendering;

        /** Array of up to 8 lights, indexed as per API
            Note that a null value indicates a free slot
          */ 
        #define MAX_LIGHTS 8
        Light* mLights[MAX_LIGHTS];

        /// 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 initConfigOptions(void);

        void setGLLight(size_t index, Light* lt);
        void makeGLMatrix(GLfloat gl_matrix[16], const Matrix4& m);
 
        GLint getBlendMode(SceneBlendFactor ogreBlend) const;
		GLint getTextureAddressingMode(TextureUnitState::TextureAddressingMode tam) const;
				void initialiseContext(RenderWindow* primary);

        void setLights();

        /// Store last depth write state
        bool mDepthWrite;
		/// Store last stencil mask state
		uint32 mStencilWriteMask;
		/// Store last colour write state
		bool mColourWrite[4];

		/// Store scissor box
		int mScissorBox[4];

        GLint convertCompareFunction(CompareFunction func) const;
        GLint convertStencilOp(StencilOperation op, bool invert = false) const;

		/// Internal method for anisotropy validation
		GLfloat _getCurrentAnisotropy(size_t unit);
		
        /// GL support class, used for creating windows etc.
        GLSupport* mGLSupport;
        
        /// Internal method to set pos / direction of a light
        void setGLLightPositionDirection(Light* lt, GLenum lightindex);

        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;

        GLuint getCombinedMinMipFilter(void) const;

        GLGpuProgram* mCurrentVertexProgram;
        GLGpuProgram* mCurrentFragmentProgram;
		GLGpuProgram* mCurrentGeometryProgram;

		/* The main GL context - main thread only */
        GLContext *mMainContext;
        /* The current GL context  - main thread only */
        GLContext *mCurrentContext;
		typedef list<GLContext*>::type GLContextList;
		/// List of background thread contexts
		GLContextList mBackgroundContextList;

		GLStateCacheManager* mStateCacheManager;

        /** Manager object for creating render textures.
            Direct render to texture via GL_EXT_framebuffer_object is preferable 
			to pbuffers, which depend on the GL support used and are generally 
			unwieldy and slow. However, FBO support for stencil buffers is poor.
        */
        GLRTTManager *mRTTManager;

        ushort mActiveTextureUnit;
        ushort mMaxBuiltInTextureAttribIndex;

        // local data members of _render that were moved here to improve performance
        // (save allocations)
        vector<GLuint>::type mRenderAttribsBound;
        vector<GLuint>::type mRenderInstanceAttribsBound;


	protected:
		void setClipPlanesImpl(const PlaneList& clipPlanes);
        void bindVertexElementToGpu( const VertexElement &elem, HardwareVertexBufferSharedPtr vertexBuffer,
                const size_t vertexStart, 
                vector<GLuint>::type &attribsBound, vector<GLuint>::type &instanceAttribsBound );
    public:
        // Default constructor / destructor
        GLRenderSystem();
        ~GLRenderSystem();

        // ----------------------------------
        // Overridden RenderSystem functions
        // ----------------------------------
        /** See
          RenderSystem
         */
        const String& getName(void) const;
        /** See
          RenderSystem
         */
        ConfigOptionMap& getConfigOptions(void);
        /** See
          RenderSystem
         */
        void setConfigOption(const String &name, const String &value);
        /** See
          RenderSystem
         */
        String validateConfigOptions(void);
        /** See
          RenderSystem
         */
        RenderWindow* _initialise(bool autoCreateWindow, const String& windowTitle = "OGRE Render Window");
        /** See
          RenderSystem
         */
        virtual RenderSystemCapabilities* createRenderSystemCapabilities() const;
        /** See
          RenderSystem
         */
        void initialiseFromRenderSystemCapabilities(RenderSystemCapabilities* caps, RenderTarget* primary);
        /** See
          RenderSystem
         */
        void reinitialise(void); // Used if settings changed mid-rendering
        /** See
          RenderSystem
         */
        void shutdown(void);

        /** See
          RenderSystem
         */
        void setAmbientLight(float r, float g, float b);
        /** See
          RenderSystem
         */
        void setShadingType(ShadeOptions so);
        /** See
          RenderSystem
         */
        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 );

        /// Mimics D3D9RenderSystem::_getDepthStencilFormatFor, if no FBO RTT manager, outputs GL_NONE
        void _getDepthStencilFormatFor( GLenum internalColourFormat, GLenum *depthFormat,
                                        GLenum *stencilFormat );
		
        /// @copydoc RenderSystem::createMultiRenderTarget
        virtual MultiRenderTarget * createMultiRenderTarget(const String & name); 
		
        /** See
          RenderSystem
         */
        void destroyRenderWindow(RenderWindow* pWin);
        /** See
          RenderSystem
         */
        String getErrorDescription(long errorNumber) const;

        /** See
          RenderSystem
         */
        VertexElementType getColourVertexElementType(void) const;
        /** See
          RenderSystem
         */
        void setNormaliseNormals(bool normalise);

        // -----------------------------
        // Low-level overridden members
        // -----------------------------
        /** See
          RenderSystem
         */
        void _useLights(const LightList& lights, unsigned short limit);
        /** See
          RenderSystem
         */
		bool areFixedFunctionLightsInViewSpace() const { return true; }
        /** See
          RenderSystem
         */
        void _setWorldMatrix(const Matrix4 &m);
        /** See
          RenderSystem
         */
        void _setViewMatrix(const Matrix4 &m);
        /** See
          RenderSystem
         */
        void _setProjectionMatrix(const Matrix4 &m);
        /** See
          RenderSystem
         */
        void _setSurfaceParams(const ColourValue &ambient,
            const ColourValue &diffuse, const ColourValue &specular,
            const ColourValue &emissive, Real shininess,
            TrackVertexColourType tracking);
        /** See
          RenderSystem
         */
		void _setPointParameters(Real size, bool attenuationEnabled, 
			Real constant, Real linear, Real quadratic, Real minSize, Real maxSize);
        /** See
          RenderSystem
         */
		void _setPointSpritesEnabled(bool enabled);
		/** See
          RenderSystem
         */
        void _setTexture(size_t unit, bool enabled, const TexturePtr &tex);
        /** See
          RenderSystem
         */
        void _setTextureCoordSet(size_t stage, size_t index);
        /** See
          RenderSystem
         */
        void _setTextureCoordCalculation(size_t stage, TexCoordCalcMethod m, 
            const Frustum* frustum = 0);
        /** See
          RenderSystem
         */
        void _setTextureBlendMode(size_t stage, const LayerBlendModeEx& bm);
        /** See
          RenderSystem
         */
        void _setTextureAddressingMode(size_t stage, const TextureUnitState::UVWAddressingMode& uvw);
        /** See
          RenderSystem
         */
        void _setTextureBorderColour(size_t stage, const ColourValue& colour);
		/** See
		  RenderSystem
		 */
		void _setTextureMipmapBias(size_t unit, float bias);
        /** See
          RenderSystem
         */
        void _setTextureMatrix(size_t stage, const Matrix4& xform);
        /** See
          RenderSystem
         */
        void _setSceneBlending(SceneBlendFactor sourceFactor, SceneBlendFactor destFactor, SceneBlendOperation op );
        /** See
          RenderSystem
         */
		void _setSeparateSceneBlending(SceneBlendFactor sourceFactor, SceneBlendFactor destFactor, SceneBlendFactor sourceFactorAlpha, SceneBlendFactor destFactorAlpha, SceneBlendOperation op, SceneBlendOperation alphaOp );
        /** See
          RenderSystem
         */
		void _setSceneBlendingOperation(SceneBlendOperation op);
		/** See
          RenderSystem
         */
		void _setSeparateSceneBlendingOperation(SceneBlendOperation op, SceneBlendOperation alphaOp);
		/** See
          RenderSystem
         */
        void _setAlphaRejectSettings(CompareFunction func, unsigned char value, bool alphaToCoverage);
        /** See
          RenderSystem
         */
        void _setViewport(Viewport *vp);
        /** See
          RenderSystem
         */
        void _beginFrame(void);
        /** See
          RenderSystem
         */
        void _endFrame(void);
        /** See
          RenderSystem
         */
        void _setCullingMode(CullingMode mode);
        /** See
          RenderSystem
         */
        void _setDepthBufferParams(bool depthTest = true, bool depthWrite = true, CompareFunction depthFunction = CMPF_LESS_EQUAL);
        /** See
          RenderSystem
         */
        void _setDepthBufferCheckEnabled(bool enabled = true);
        /** See
          RenderSystem
         */
        void _setDepthBufferWriteEnabled(bool enabled = true);
        /** See
          RenderSystem
         */
        void _setDepthBufferFunction(CompareFunction func = CMPF_LESS_EQUAL);
        /** See
          RenderSystem
         */
        void _setDepthBias(float constantBias, float slopeScaleBias);
        /** See
          RenderSystem
         */
        void _setColourBufferWriteEnabled(bool red, bool green, bool blue, bool alpha);
		/** See
          RenderSystem
         */
        void _setFog(FogMode mode, const ColourValue& colour, Real density, Real start, Real end);
        /** See
          RenderSystem
         */
        void _convertProjectionMatrix(const Matrix4& matrix,
            Matrix4& dest, bool forGpuProgram = false);
        /** See
          RenderSystem
         */
        void _makeProjectionMatrix(const Radian& fovy, Real aspect, Real nearPlane, Real farPlane, 
            Matrix4& dest, bool forGpuProgram = false);
        /** See
          RenderSystem
         */
        void _makeProjectionMatrix(Real left, Real right, Real bottom, Real top, 
            Real nearPlane, Real farPlane, Matrix4& dest, bool forGpuProgram = false);
        /** See
          RenderSystem
         */
		void _makeOrthoMatrix(const Radian& fovy, Real aspect, Real nearPlane, Real farPlane, 
            Matrix4& dest, bool forGpuProgram = false);
        /** See
        RenderSystem
        */
        void _applyObliqueDepthProjection(Matrix4& matrix, const Plane& plane, 
            bool forGpuProgram);
        /** See
          RenderSystem
         */
        void setClipPlane (ushort index, Real A, Real B, Real C, Real D);
        /** See
          RenderSystem
         */
        void enableClipPlane (ushort index, bool enable);
        /** See
          RenderSystem
         */
        void _setPolygonMode(PolygonMode level);
        /** See
          RenderSystem
         */
        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);
        /** See
          RenderSystem
         */
        void _setTextureUnitFiltering(size_t unit, FilterType ftype, FilterOptions filter);
		 /** See
          RenderSystem
         */
		void _setTextureUnitCompareFunction(size_t unit, CompareFunction function);
		 /** See
          RenderSystem
         */
		void _setTextureUnitCompareEnabled(size_t unit, bool compare);
        /** See
          RenderSystem
         */
		void _setTextureLayerAnisotropy(size_t unit, unsigned int maxAnisotropy);
        /** See
          RenderSystem
         */
		void setVertexDeclaration(VertexDeclaration* decl);
        /** See
          RenderSystem
         */
		void setVertexBufferBinding(VertexBufferBinding* binding);
        /** See
          RenderSystem
         */
        void _render(const RenderOperation& op);

        /** See
          RenderSystem
         */
        void bindGpuProgram(GpuProgram* prg);
        /** See
          RenderSystem
         */
        void unbindGpuProgram(GpuProgramType gptype);
        /** See
          RenderSystem
         */
        void bindGpuProgramParameters(GpuProgramType gptype, 
                                      GpuProgramParametersSharedPtr params, uint16 variabilityMask);
        /** See
            RenderSystem
        */
        void bindGpuProgramPassIterationParameters(GpuProgramType gptype);
        /** See
          RenderSystem
         */
        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);
        Real getHorizontalTexelOffset(void);
        Real getVerticalTexelOffset(void);
        Real getMinimumDepthInputValue(void);
        Real getMaximumDepthInputValue(void);
        OGRE_MUTEX(mThreadInitMutex);
        void registerThread();
        void unregisterThread();
        void preExtraThreadsStarted();
        void postExtraThreadsStarted();
        GLSupport* getGLSupportRef() { return mGLSupport; }

        // ----------------------------------
        // GLRenderSystem specific members
        // ----------------------------------
        /** One time initialization for the RenderState of a context. Things that
            only need to be set once, like the LightingModel can be defined here.
         */
        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);
		/** Returns the main context */
		GLContext* _getMainContext() {return mMainContext;} 

		/// @copydoc RenderSystem::getDisplayMonitorCount
		unsigned int getDisplayMonitorCount() const;

		/// @copydoc RenderSystem::hasAnisotropicMipMapFilter
		virtual bool hasAnisotropicMipMapFilter() const { return false; }
        
		/// @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 );
    };
}
#endif

