C++ GpuProgramParametersSharedPtr::_writeRawConstants方法代码示例

//.........这里部分代码省略.........
   vRight.normalise();
   vUp.normalise();

   //Even if camera is upside down, the billboards should remain upright
   if (vUp.y < 0)
      vUp *= -1;

   // Precompute preRotatedQuad for both cases (BBO_CENTER, BBO_BOTTOM_CENTER)
   
   Vector3 vPoint0 = (-vRight + vUp);
   Vector3 vPoint1 = ( vRight + vUp);
   Vector3 vPoint2 = (-vRight - vUp);
   Vector3 vPoint3 = ( vRight - vUp);

   float preRotatedQuad_BBO_CENTER[16] = // single prerotated quad oriented towards the camera
   {
      (float)vPoint0.x, (float)vPoint0.y, (float)vPoint0.z, 0.0f,
      (float)vPoint1.x, (float)vPoint1.y, (float)vPoint1.z, 0.0f,
      (float)vPoint2.x, (float)vPoint2.y, (float)vPoint2.z, 0.0f,
      (float)vPoint3.x, (float)vPoint3.y, (float)vPoint3.z, 0.0f
   };

   vPoint0 = (-vRight + vUp + vUp);
   vPoint1 = ( vRight + vUp + vUp);
   vPoint2 = (-vRight);
   vPoint3 = ( vRight);
   float preRotatedQuad_BBO_BOTTOM_CENTER[16] =
   {
      (float)vPoint0.x, (float)vPoint0.y, (float)vPoint0.z, 0.0f,
      (float)vPoint1.x, (float)vPoint1.y, (float)vPoint1.z, 0.0f,
      (float)vPoint2.x, (float)vPoint2.y, (float)vPoint2.z, 0.0f,
      (float)vPoint3.x, (float)vPoint3.y, (float)vPoint3.z, 0.0f
   };

   // Shaders uniform variables
   static const Ogre::String uScroll = "uScroll", vScroll = "vScroll", preRotatedQuad0 = "preRotatedQuad[0]",
      preRotatedQuad1 = "preRotatedQuad[1]", preRotatedQuad2 = "preRotatedQuad[2]", preRotatedQuad3 = "preRotatedQuad[3]";

   // SVA for Ogre::Material hack
   const GpuConstantDefinition *pGPU_ConstDef_preRotatedQuad0 = 0,
      *pGPU_ConstDef_uScroll = 0, *pGPU_ConstDef_vScroll = 0;

   // For each material in use by the billboard system..
   SBMaterialRefList::iterator i1 = SBMaterialRef::getList().begin(), iend = SBMaterialRef::getList().end();
   while (i1 != iend)
   {
      Ogre::Material *mat = i1->second->getMaterial();

      // Ensure material is set up with the vertex shader
      Pass *p = mat->getTechnique(0)->getPass(0);
      if (!p->hasVertexProgram())
      {
         static const Ogre::String Sprite_vp = "Sprite_vp";
         p->setVertexProgram(Sprite_vp);

         // glsl can use the built in gl_ModelViewProjectionMatrix
         if (!s_isGLSL)
            p->getVertexProgramParameters()->setNamedAutoConstant("worldViewProj", GpuProgramParameters::ACT_WORLDVIEWPROJ_MATRIX);

         GpuProgramParametersSharedPtr params = p->getVertexProgramParameters();
         params->setNamedAutoConstant(uScroll, GpuProgramParameters::ACT_CUSTOM);
         params->setNamedAutoConstant(vScroll, GpuProgramParameters::ACT_CUSTOM);
         params->setNamedAutoConstant(preRotatedQuad0, GpuProgramParameters::ACT_CUSTOM);
         params->setNamedAutoConstant(preRotatedQuad1, GpuProgramParameters::ACT_CUSTOM);
         params->setNamedAutoConstant(preRotatedQuad2, GpuProgramParameters::ACT_CUSTOM);
         params->setNamedAutoConstant(preRotatedQuad3, GpuProgramParameters::ACT_CUSTOM);
      }

      // Which prerotated quad use
      const float *pQuad = i1->second->getOrigin() == BBO_CENTER ? preRotatedQuad_BBO_CENTER : preRotatedQuad_BBO_BOTTOM_CENTER;

      // Update the vertex shader parameters
      GpuProgramParametersSharedPtr params = p->getVertexProgramParameters();
      //params->setNamedConstant(preRotatedQuad0, pQuad, 4);
      //params->setNamedConstant(uScroll, p->getTextureUnitState(0)->getTextureUScroll());
      //params->setNamedConstant(vScroll, p->getTextureUnitState(0)->getTextureVScroll());

      // SVA some hack of Ogre::Material.
      // Since material are cloned and use same vertex shader "Sprite_vp" hardware GPU indices
      // must be same. I don`t know planes of Ogre Team to change this behaviour.
      // Therefore this may be unsafe code. Instead of 3 std::map lookups(map::find(const Ogre::String&)) do only 1
      {
         const GpuConstantDefinition *def = params->_findNamedConstantDefinition(preRotatedQuad0, true);
         if (def != pGPU_ConstDef_preRotatedQuad0) // new material, reread
         {
            pGPU_ConstDef_preRotatedQuad0 = def;
            pGPU_ConstDef_uScroll         = params->_findNamedConstantDefinition(uScroll, true);
            pGPU_ConstDef_vScroll         = params->_findNamedConstantDefinition(vScroll, true);
         }
      }

      float fUScroll = (float)p->getTextureUnitState(0)->getTextureUScroll(),
         fVScroll = (float)p->getTextureUnitState(0)->getTextureVScroll();
      params->_writeRawConstants(pGPU_ConstDef_preRotatedQuad0->physicalIndex, pQuad, 16);
      params->_writeRawConstants(pGPU_ConstDef_uScroll->physicalIndex, &fUScroll, 1);
      params->_writeRawConstants(pGPU_ConstDef_vScroll->physicalIndex, &fVScroll, 1);
      
      ++i1; // next material in billboard system
   }
}