关于DepthPartition与天空球结合的几个问题

Mooneast

做了这样一个实验工程，使用《OSG编程实践》中的立方图纹理做了一个天空球，如下：

1. struct TexMatCallback:public osg::NodeCallback
   
2. {
   
3. public:
   
4.         TexMatCallback(osg::TexMat& tm):_texMat(tm)
   
5.         {
   
6. 
   
7.         }
   
8. 
   
9.         virtual void operator()(osg::Node*node,osg::NodeVisitor*nv)
   
10.         {
    
11.                 osgUtil::CullVisitor* cv=dynamic_cast<osgUtil::CullVisitor*>(nv);
    
12.                 if (cv)
    
13.                 {
    
14.                         const osg::Matrix& mv=*(cv->getModelViewMatrix());
    
15.                         const osg::Matrix R=osg::Matrix::rotate(osg::DegreesToRadians(112.0f),0.0f,0.0f,1.0f)*osg::Matrix::rotate(osg::DegreesToRadians(90.0f),1.0f,0.0f,0.0f);
    
16. 
    
17.                         osg::Quat q=mv.getRotate();
    
18.                         const osg::Matrix C=osg::Matrix::rotate(q.inverse());
    
19. 
    
20.                         _texMat.setMatrix(C*R);
    
21.                 }
    
22. 
    
23.                 traverse(node,nv);
    
24.         }
    
25. 
    
26.         osg::TexMat& _texMat;
    
27. };
    
28. 
    
29. class MoveWithEyePoint:public osg::Transform
    
30. {
    
31. public:
    
32.         MoveWithEyePoint()
    
33.         {
    
34.         }
    
35. 
    
36.         ~MoveWithEyePoint()
    
37.         {
    
38. 
    
39.         }
    
40. 
    
41.         virtual bool computeLocalToWorldMatrix(osg::Matrix& matrix,osg::NodeVisitor*nv)const
    
42.         {
    
43.                 osgUtil::CullVisitor* cv=dynamic_cast<osgUtil::CullVisitor*>(nv);
    
44. 
    
45.                 if (cv)
    
46.                 {
    
47.                         osg::Vec3 eyePointLocal=cv->getEyeLocal();
    
48.                         matrix.preMult(osg::Matrix::translate(eyePointLocal));
    
49.                 }
    
50. 
    
51.                 return true;
    
52.         }
    
53. 
    
54.         virtual bool computeWorldToLocalMatrix(osg::Matrix& matrix,osg::NodeVisitor*nv)const
    
55.         {
    
56.                 osgUtil::CullVisitor* cv=dynamic_cast<osgUtil::CullVisitor*>(nv);
    
57. 
    
58.                 if (cv)
    
59.                 {
    
60.                         osg::Vec3 eyePointLocal=cv->getEyeLocal();
    
61.                         matrix.postMult(osg::Matrix::translate(-eyePointLocal));
    
62.                 }
    
63. 
    
64.                 return true;
    
65.         }
    
66. };
    
67. //创建天空球函数
    
68. osg::ref_ptr<osg::Node> CreateSphere(void)
    
69. {
    
70.         osg::ref_ptr<osg::Image> srcImage=osgDB::readImageFile(m_strBackGroundFile);
    
71. 
    
72.         unsigned width=srcImage->s()/4;
    
73.         unsigned height=srcImage->t()/3;
    
74. 
    
75.         //下面的代码是用来将一个整张的图片中的几个面的贴图截出来的，与主题没有太大关系
    
76.         osg::ref_ptr<osg::Image> topImage=getSubImage(srcImage,width,height*2,0,width,height,1);
    
77.         osg::ref_ptr<osg::Image> bottomImage=getSubImage(srcImage,width,0,0,width,height,1);
    
78.         osg::ref_ptr<osg::Image> rightImage=getSubImage(srcImage,width*2,height,0,width,height,1);
    
79.         osg::ref_ptr<osg::Image> leftImage=getSubImage(srcImage,0,height,0,width,height,1);
    
80.         osg::ref_ptr<osg::Image> frontImage=getSubImage(srcImage,width,height,0,width,height,1);
    
81.         osg::ref_ptr<osg::Image> backImage=getSubImage(srcImage,width*3,height,0,width,height,1);
    
82. 
    
83.         osg::ref_ptr<osg::TextureCubeMap> tcm=new osg::TextureCubeMap;
    
84. 
    
85.         {
    
86.                 tcm->setImage(osg::TextureCubeMap::POSITIVE_X,rightImage);
    
87.                 tcm->setImage(osg::TextureCubeMap::NEGATIVE_X,leftImage);
    
88.                 tcm->setImage(osg::TextureCubeMap::POSITIVE_Y,bottomImage);
    
89.                 tcm->setImage(osg::TextureCubeMap::NEGATIVE_Y,topImage);
    
90.                 tcm->setImage(osg::TextureCubeMap::POSITIVE_Z,frontImage);
    
91.                 tcm->setImage(osg::TextureCubeMap::NEGATIVE_Z,backImage);
    
92. 
    
93.                 tcm->setWrap(osg::Texture::WRAP_S,osg::Texture::CLAMP_TO_EDGE);
    
94.                 tcm->setWrap(osg::Texture::WRAP_T,osg::Texture::CLAMP_TO_EDGE);
    
95.                 tcm->setWrap(osg::Texture::WRAP_R,osg::Texture::CLAMP_TO_EDGE);
    
96. 
    
97.                 tcm->setFilter(osg::Texture::MIN_FILTER,osg::Texture::LINEAR_MIPMAP_NEAREST);
    
98.                 tcm->setFilter(osg::Texture::MAG_FILTER,osg::Texture::LINEAR);
    
99.         }
    
100. 
     
101.         osg::ref_ptr<osg::StateSet> stateset=new osg::StateSet;
     
102. 
     
103.         osg::ref_ptr<osg::TexEnv> te=new osg::TexEnv;
     
104.         te->setMode(osg::TexEnv::REPLACE);
     
105.         stateset->setTextureAttributeAndModes(0,te,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
     
106. 
     
107.         osg::ref_ptr<osg::TexGen> tg=new osg::TexGen;
     
108.         tg->setMode(osg::TexGen::NORMAL_MAP);
     
109.         stateset->setTextureAttributeAndModes(0,tg,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
     
110. 
     
111.         osg::ref_ptr<osg::TexMat> tm=new osg::TexMat;
     
112.         stateset->setTextureAttribute(0,tm);
     
113. 
     
114.         stateset->setTextureAttributeAndModes(0,tcm,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
     
115. 
     
116.         stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
     
117.         stateset->setMode(GL_CULL_FACE,osg::StateAttribute::OFF);
     
118. 
     
119.         osg::ref_ptr<osg::Depth> depth=new osg::Depth;
     
120.         depth->setFunction(osg::Depth::ALWAYS);
     
121.         depth->setRange(1.0,1.0);
     
122.         stateset->setAttributeAndModes(depth,osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE);
     
123. 
     
124.         stateset->setRenderBinDetails(-1,"RenderBin");
     
125. 
     
126.         osg::ref_ptr<osg::Drawable> drawable=new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0,0.0,0.0),1.0));
     
127. 
     
128.         osg::ref_ptr<osg::Geode> geode=new osg::Geode;
     
129.         geode->setCullingActive(false);
     
130.         geode->setStateSet(stateset);
     
131.         geode->addDrawable(drawable);
     
132. 
     
133.         osg::ref_ptr<osg::Transform> transform=new MoveWithEyePoint();
     
134.         transform->addChild(geode);
     
135.         transform->setCullingActive(false);
     
136.         transform->setCullCallback(new TexMatCallback(*tm));
     
137. 
     
138.         return transform;
     
139. }

复制代码

在主函数中，实现如下：

1. int main()
   
2. {
   
3.         osg::ref_ptr<osgViewer::Viewer> viewer=new osgViewer::Viewer;
   
4. 
   
5.         osg::ref_ptr<osg::Group> root=new osg::Group;
   
6.         osg::ref_ptr<osg::Node> scene=osgDB::readNodeFile("lz.osg");
   
7.         osg::ref_ptr<osg::Node> node=CreateSphere();
   
8. 
   
9.         osg::ref_ptr<osg::GraphicsContext::Traits> traits=new osg::GraphicsContext::Traits;
   
10.         traits->x=400;
    
11.         traits->y=50;
    
12.         traits->width=800;
    
13.         traits->height=600;
    
14.         traits->windowName="Main";
    
15.         traits->windowDecoration=true;
    
16.         traits->sharedContext=0;
    
17.         traits->doubleBuffer=true;
    
18.         traits->stencil=8;
    
19. 
    
20.         osg::ref_ptr<osg::GraphicsContext> gc=osg::GraphicsContext::createGraphicsContext(traits);
    
21. 
    
22.         if (gc->valid())
    
23.         {
    
24.                 gc->setClearColor(osg::Vec4(1.0,0.0,0.0,1.0));
    
25.                 gc->setClearMask(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);
    
26.         }else{
    
27.                 std::cout<<"Graphics has not been created !"<<std::endl;
    
28.         }
    
29. 
    
30.         osg::Vec3 eye(scene->getBound().center().x(),scene->getBound().center().y()-scene->getBound().radius(),scene->getBound().center().z());
    
31.         osg::Vec3 center(scene->getBound().center().x(),scene->getBound().center().y(),scene->getBound().center().z());
    
32.         osg::Vec3 up(0.0,0.0,1.0);
    
33.         {
    
34.                 osg::ref_ptr<osgViewer::DepthPartitionSettings> dps=new osgViewer::DepthPartitionSettings;
    
35. 
    
36.                 dps->_mode = osgViewer::DepthPartitionSettings::FIXED_RANGE;
    
37.                 dps->_zNear=1.0;
    
38.                 dps->_zMid=scene->getBound().radius()*0.7;
    
39.                 dps->_zFar=scene->getBound().radius();
    
40. 
    
41.                 viewer->setUpDepthPartition(dps);
    
42. 
    
43.                 viewer->getCamera()->setGraphicsContext(gc);
    
44.                 viewer->getCamera()->setViewport(0,0,traits->width,traits->height);
    
45. 
    
46.                 viewer->getSlave(0)._camera->setGraphicsContext(gc);
    
47.                 viewer->getSlave(0)._camera->setViewport(0,traits->height/2,traits->width/2,traits->height/2);
    
48.                 viewer->getSlave(0)._camera->setAllowEventFocus(false);
    
49. 
    
50.                 viewer->getSlave(1)._camera->setGraphicsContext(gc);
    
51.                 viewer->getSlave(1)._camera->setViewport(0,0,traits->width/2,traits->height/2);
    
52.                 viewer->getSlave(1)._camera->setAllowEventFocus(false);
    
53. 
    
54.                 viewer->addEventHandler(new osgGA::StateSetManipulator(viewer->getSlave(1)._camera->getOrCreateStateSet()));
    
55. 
    
56.                 std::cout<<viewer->getNumSlaves()<<std::endl;
    
57.         }
    
58. 
    
59.         root->addChild(node);
    
60.         root->addChild(scene);
    
61. 
    
62.         viewer->setSceneData(root);
    
63.         viewer->setCameraManipulator(new osgGA::TrackballManipulator);
    
64.         viewer->getCameraManipulator()->setHomePosition(eye,center,up,false);
    
65.         viewer->home();
    
66.         viewer->run();
    
67.         return 0;
    
68. }

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运行的结果很奇怪，只有最后一个加入的相机被渲染出来了，但是实际上的从属相机个数仍为2，此外当视点距离scene很远的时候，会造成天空球的裁剪，情况如下图。

Mooneast

顶下，莫沉啊

Mooneast

求指导啊

array

我在另一个帖子里已经说过了，DepthPartition会建立多个Slave，这种方式我很不喜欢。如果您一定要用的话，就要考虑到场景会被多个Slave渲染多次的问题，而您的天空球应当只在最后一个Slave中被渲染