irr/include/IShaderConstantSetCallBack.h

   1 // Copyright (C) 2002-2012 Nikolaus Gebhardt
   2 // This file is part of the "Irrlicht Engine".
   3 // For conditions of distribution and use, see copyright notice in irrlicht.h
   4
   5 #pragma once
   6
   7 #include "IReferenceCounted.h"
   8
   9 namespace irr
  10 {
  11 namespace video
  12 {
  13 class IMaterialRendererServices;
  14 class SMaterial;
  15
  16 //! Interface making it possible to set constants for gpu programs every frame.
  17 /** Implement this interface in an own class and pass a pointer to it to one of
  18 the methods in IGPUProgrammingServices when creating a shader. The
  19 OnSetConstants method will be called every frame now. */
  20 class IShaderConstantSetCallBack : public virtual IReferenceCounted
  21 {
  22 public:
  23         //! Called to let the callBack know the used material (optional method)
  24         /**
  25          \code
  26         class MyCallBack : public IShaderConstantSetCallBack
  27         {
  28                 const video::SMaterial *UsedMaterial;
  29
  30                 OnSetMaterial(const video::SMaterial& material)
  31                 {
  32                         UsedMaterial=&material;
  33                 }
  34
  35                 OnSetConstants(IMaterialRendererServices* services, s32 userData)
  36                 {
  37                         services->setVertexShaderConstant("myColor", reinterpret_cast<f32*>(&UsedMaterial->color), 4);
  38                 }
  39         }
  40         \endcode
  41         */
  42         virtual void OnSetMaterial(const SMaterial &material) {}
  43
  44         //! Called by the engine when the vertex and/or pixel shader constants for an material renderer should be set.
  45         /**
  46         Implement the IShaderConstantSetCallBack in an own class and implement your own
  47         OnSetConstants method using the given IMaterialRendererServices interface.
  48         Pass a pointer to this class to one of the methods in IGPUProgrammingServices
  49         when creating a shader. The OnSetConstants method will now be called every time
  50         before geometry is being drawn using your shader material. A sample implementation
  51         would look like this:
  52         \code
  53         virtual void OnSetConstants(video::IMaterialRendererServices* services, s32 userData)
  54         {
  55                 video::IVideoDriver* driver = services->getVideoDriver();
  56
  57                 // set clip matrix at register 4
  58                 core::matrix4 worldViewProj(driver->getTransform(video::ETS_PROJECTION));
  59                 worldViewProj *= driver->getTransform(video::ETS_VIEW);
  60                 worldViewProj *= driver->getTransform(video::ETS_WORLD);
  61                 services->setVertexShaderConstant(&worldViewProj.M[0], 4, 4);
  62                 // for high level shading languages, this would be another solution:
  63                 //services->setVertexShaderConstant("mWorldViewProj", worldViewProj.M, 16);
  64
  65                 // set some light color at register 9
  66                 video::SColorf col(0.0f,1.0f,1.0f,0.0f);
  67                 services->setVertexShaderConstant(reinterpret_cast<const f32*>(&col), 9, 1);
  68                 // for high level shading languages, this would be another solution:
  69                 //services->setVertexShaderConstant("myColor", reinterpret_cast<f32*>(&col), 4);
  70         }
  71         \endcode
  72         \param services: Pointer to an interface providing methods to set the constants for the shader.
  73         \param userData: Userdata int which can be specified when creating the shader.
  74         */
  75         virtual void OnSetConstants(IMaterialRendererServices *services, s32 userData) = 0;
  76 };
  77
  78 } // end namespace video
  79 } // end namespace irr