DtVariableRateShadingImage.h

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/******************************************************************************
** Copyright (c) 2020 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/


#pragma once

#include <vrvOsg/DtOsgChannel.h>
#include <vrvGraphicsUtils/DtGlRenderToTexture.h>

#include <string>

#ifndef GL_NV_shading_rate_image
#define GL_NV_shading_rate_image 1
#define GL_SHADING_RATE_IMAGE_NV          0x9563
#define GL_SHADING_RATE_NO_INVOCATIONS_NV 0x9564
#define GL_SHADING_RATE_1_INVOCATION_PER_PIXEL_NV 0x9565
#define GL_SHADING_RATE_1_INVOCATION_PER_1X2_PIXELS_NV 0x9566
#define GL_SHADING_RATE_1_INVOCATION_PER_2X1_PIXELS_NV 0x9567
#define GL_SHADING_RATE_1_INVOCATION_PER_2X2_PIXELS_NV 0x9568
#define GL_SHADING_RATE_1_INVOCATION_PER_2X4_PIXELS_NV 0x9569
#define GL_SHADING_RATE_1_INVOCATION_PER_4X2_PIXELS_NV 0x956A
#define GL_SHADING_RATE_1_INVOCATION_PER_4X4_PIXELS_NV 0x956B
#define GL_SHADING_RATE_2_INVOCATIONS_PER_PIXEL_NV 0x956C
#define GL_SHADING_RATE_4_INVOCATIONS_PER_PIXEL_NV 0x956D
#define GL_SHADING_RATE_8_INVOCATIONS_PER_PIXEL_NV 0x956E
#define GL_SHADING_RATE_16_INVOCATIONS_PER_PIXEL_NV 0x956F
#define GL_SHADING_RATE_IMAGE_BINDING_NV  0x955B
#define GL_SHADING_RATE_IMAGE_TEXEL_WIDTH_NV 0x955C
#define GL_SHADING_RATE_IMAGE_TEXEL_HEIGHT_NV 0x955D
#define GL_SHADING_RATE_IMAGE_PALETTE_SIZE_NV 0x955E
#define GL_MAX_COARSE_FRAGMENT_SAMPLES_NV 0x955F
#define GL_SHADING_RATE_SAMPLE_ORDER_DEFAULT_NV 0x95AE
#define GL_SHADING_RATE_SAMPLE_ORDER_PIXEL_MAJOR_NV 0x95AF
#define GL_SHADING_RATE_SAMPLE_ORDER_SAMPLE_MAJOR_NV 0x95B0
#endif /* GL_NV_shading_rate_image */


namespace makVrv
{
    class DtVariableRateShadingImage;


    class DT_DLL_VRVOSG VariableRateShadingExtensions : public osg::Referenced
    {
    public:
        static VariableRateShadingExtensions* Get(unsigned int contextID, bool createIfNotInitalized);

        VariableRateShadingExtensions(unsigned int in_contextID);

        void (GL_APIENTRY * glBindShadingRateImageNV) (GLuint texture);
        void (GL_APIENTRY * glGetShadingRateImagePaletteNV) (GLuint viewport, GLuint entry, GLenum *rate);
        void (GL_APIENTRY * glGetShadingRateSampleLocationivNV) (GLenum rate, GLuint samples, GLuint index, GLint *location);
        void (GL_APIENTRY * glShadingRateImageBarrierNV) (GLboolean synchronize);
        void (GL_APIENTRY * glShadingRateImagePaletteNV) (GLuint viewport, GLuint first, GLsizei count, const GLenum *rates);
        void (GL_APIENTRY * glShadingRateSampleOrderNV) (GLenum order);
        void (GL_APIENTRY * glShadingRateSampleOrderCustomNV) (GLenum rate, GLuint samples, const GLint *locations);
   };

   class DT_DLL_VRVOSG DtVariableRateShadingImage : public osg::Referenced
   {
   private:
       DtVariableRateShadingImage(const DtVariableRateShadingImage& other);

       DtVariableRateShadingImage& operator=(const DtVariableRateShadingImage &other);

   public:
      typedef std::vector<unsigned char> VariableRatePixelBuffer;

      DtVariableRateShadingImage(DtDe& de, DtOsgChannel* channel);

      void initGLObjects(osg::State& state);

      bool createShadingRateImageTextureForChannel(osg::State& state);

      unsigned int imageWidth() const;

      unsigned int imageHeight() const;

      unsigned int shadingRateTexelWidth() const;

      unsigned int shadingRateTexelHeight() const;

      void useImageData(bool useData);

      void dirtyImageData();

      std::vector<VariableRatePixelBuffer>& imageData();

      DtGlRenderTexture* texture();

      void bindShadingImage(osg::State& state);

      bool isInitalised() { return myExt != NULL && myIsInitalised; }

      void reset() { myIsInitalised  = false; }

      static void populateDataForvated(int width, int height, float centerX, float centerY, VariableRatePixelBuffer &data);

      //  focusval and context val are indicies into the variable rate shading image palette
      static void populateDataFocusRect(int width, int height, float focusMinX, float focusMinY, float focusMaxX, float focusMaxY, unsigned char focusVal, unsigned char contextVal, VariableRatePixelBuffer& data);

   protected:
       virtual ~DtVariableRateShadingImage();

       void loadImageData(osg::State& state);

   protected:
      DtDe& myDe;
      DtOsgChannel* myChannel;

      VariableRateShadingExtensions* myExt;
      bool myIsInitalised;

      DtGlRenderTexture* myShadingRateTexture;

      GLint myShadingRateImageTexelWidth;
      GLint myShadingRateImageTexelHeight;

      std::vector<VariableRatePixelBuffer> myShadingRateImageData;
      bool myUseImageData;
      bool myShadingRateTextureIsDirty;
   };

   class DT_DLL_VRVOSG DtVariableRateShadingImageStateAttribute : public osg::StateAttribute
   {
   public:

       static const osg::StateAttribute::Type VariableRateShadingImageStateAttributeType = (osg::StateAttribute::Type)3000;

       DtVariableRateShadingImageStateAttribute(DtVariableRateShadingImage* image = NULL);

       ~DtVariableRateShadingImageStateAttribute();

       DtVariableRateShadingImageStateAttribute(const DtVariableRateShadingImageStateAttribute& stateAttrib, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY);

       META_StateAttribute(osg, DtVariableRateShadingImageStateAttribute, VariableRateShadingImageStateAttributeType);

       virtual bool isTextureAttribute() const;

       virtual int compare(const osg::StateAttribute& sa) const;

       virtual void apply(osg::State&) const;

       virtual void compileGLObjects(osg::State&) const;

       virtual void releaseGLObjects(osg::State* = 0) const;
       
       DtVariableRateShadingImage* shadingImage() const;

   private:

       osg::ref_ptr<DtVariableRateShadingImage> myShadingRateImage;
   };
}