整合OGRE的地形和PSSM+LiSPSM陰影演算法

OGRE版本1.7.1的Sample裡包含了地形的樣本，且用到了PSSM+LiSPSM。

今天嘗試把Character的Sinbad模型擺到地形上，不過模型的材質本身不支援PSSM。

看了下地形樣本的實現，發現它在給Shader傳PSSM分界點資料時，用了把模板材質clone一份，再設定diffusemap和pssm分界點的方法，相當讓人無語....

 

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1. MaterialPtr ret = MaterialManager::getSingleton().getByName(matName);   
2. MaterialPtr baseMat = MaterialManager::getSingleton().getByName("Ogre/shadow/depth/integrated/pssm");   
3. ret = baseMat->clone(matName);   
4. Pass* p = ret->getTechnique(0)->getPass(0);   
5. p->getTextureUnitState("diffuse")->setTextureName(textureName);   
6. Vector4 splitPoints;   
7. const PSSMShadowCameraSetup::SplitPointList& splitPointList =    
8.     static_cast<PSSMShadowCameraSetup*>(mPSSMSetup.get())->getSplitPoints();   
9. for (int i = 0; i < 3; ++i)   
10. {   
11.     splitPoints[i] = splitPointList[i];   
12. }   
13. p->getFragmentProgramParameters()->setNamedConstant("pssmSplitPoints", splitPoints);  

MaterialPtr ret = MaterialManager::getSingleton().getByName(matName);<br />MaterialPtr baseMat = MaterialManager::getSingleton().getByName("Ogre/shadow/depth/integrated/pssm");<br />ret = baseMat->clone(matName);<br />Pass* p = ret->getTechnique(0)->getPass(0);<br />p->getTextureUnitState("diffuse")->setTextureName(textureName);<br />Vector4 splitPoints;<br />const PSSMShadowCameraSetup::SplitPointList& splitPointList =<br />static_cast<PSSMShadowCameraSetup*>(mPSSMSetup.get())->getSplitPoints();<br />for (int i = 0; i < 3; ++i)<br />{<br />splitPoints[i] = splitPointList[i];<br />}<br />p->getFragmentProgramParameters()->setNamedConstant("pssmSplitPoints", splitPoints); 

 

如果有幾百種不同貼圖的物件，就得在代碼裏手動為每一個物件設定diffusemap和pssm分界點，前者其實在材質指令碼中可以用繼承來覆蓋，後者其實整個情境用到的資料都是一樣的。好在OGRE增加了shared_params，可以多個shader共用相同的參數，在代碼裡只設定一遍就可以了。

修改後的fp:

 

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1. shared_params pssm_params   
2. {   
3.     shared_param_named pssmSplitPoints float4   
4. }   
5. fragment_program Ogre/shadow/receiver/depth/pssm3/fp cg   
6. {   
7.     source depthshadowobject.cg   
8.     profiles ps_2_x arbfp1   
9.     entry_point main_fp   
10.     compile_arguments -DSHADOWCASTER=0 -DDEPTH_SHADOWCASTER=0 -DDEPTH_SHADOWRECEIVER=1    
11.     default_params   
12.     {   
13.         param_named_auto materialAmbient derived_ambient_light_colour   
14.         // shadow samplers are indexes 1/2/3   
15.         param_named_auto inverseShadowmapSize0 inverse_texture_size 1   
16.         param_named_auto inverseShadowmapSize1 inverse_texture_size 2   
17.         param_named_auto inverseShadowmapSize2 inverse_texture_size 3   
18.         //SET THIS MANUALLY!   
19.         //param_named pssmSplitPoints 0 0 0 0   
20.         shared_params_ref pssm_params   
21.     }   
22. }  

shared_params pssm_params<br />{<br />shared_param_named pssmSplitPoints float4<br />}<br />fragment_program Ogre/shadow/receiver/depth/pssm3/fp cg<br />{<br />source depthshadowobject.cg<br />profiles ps_2_x arbfp1<br />entry_point main_fp<br />compile_arguments -DSHADOWCASTER=0 -DDEPTH_SHADOWCASTER=0 -DDEPTH_SHADOWRECEIVER=1<br />default_params<br />{<br />param_named_auto materialAmbient derived_ambient_light_colour<br />// shadow samplers are indexes 1/2/3<br />param_named_auto inverseShadowmapSize0 inverse_texture_size 1<br />param_named_auto inverseShadowmapSize1 inverse_texture_size 2<br />param_named_auto inverseShadowmapSize2 inverse_texture_size 3<br />//SET THIS MANUALLY!<br />//param_named pssmSplitPoints 0 0 0 0<br />shared_params_ref pssm_params<br />}<br />} 

 

c++:

 

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1. Vector4 splitPoints;   
2. const PSSMShadowCameraSetup::SplitPointList& splitPointList =    
3. static_cast<PSSMShadowCameraSetup*>(mPSSMSetup.get())->getSplitPoints();   
4. for (int i = 0; i < 3; ++i)   
5. {   
6.     splitPoints[i] = splitPointList[i];   
7. }   
8. GpuSharedParametersPtr p = GpuProgramManager::getSingleton().getSharedParameters("pssm_params");   
9. p->setNamedConstant("pssmSplitPoints", splitPoints);  

Vector4 splitPoints;<br />const PSSMShadowCameraSetup::SplitPointList& splitPointList =<br />static_cast<PSSMShadowCameraSetup*>(mPSSMSetup.get())->getSplitPoints();<br />for (int i = 0; i < 3; ++i)<br />{<br />splitPoints[i] = splitPointList[i];<br />}<br />GpuSharedParametersPtr p = GpuProgramManager::getSingleton().getSharedParameters("pssm_params");<br />p->setNamedConstant("pssmSplitPoints", splitPoints); 

 

 

http://blog.csdn.net/cometeor/archive/2010/06/09/5657168.aspx