osg天空

柔光的暖阳◎ 2022-08-06 19:28 278阅读 0赞

[http://hi.baidu.com/janxhuilk/blog/item/7a16871b2bd941fbae5133af.html/cmtid/eb8393b4a19d267b8ad4b217][http_hi.baidu.com_janxhuilk_blog_item_7a16871b2bd941fbae5133af.html_cmtid_eb8393b4a19d267b8ad4b217]

osg::TextureCubeMap\* readCubeMap()  
\{  
osg::TextureCubeMap\* cubemap = new osg::TextureCubeMap;  
//\#define CUBEMAP\_FILENAME(face) "nvlobby\_" \#face ".png"  
//\#define CUBEMAP\_FILENAME(face) "Cubemap\_axis/" \#face ".png"  
\#define CUBEMAP\_FILENAME(face) "res/" \#face ".bmp"

osg::Image\* imagePosX = osgDB::readImageFile(CUBEMAP\_FILENAME(front));  
osg::Image\* imageNegX = osgDB::readImageFile(CUBEMAP\_FILENAME(left));  
osg::Image\* imagePosY = osgDB::readImageFile(CUBEMAP\_FILENAME(down));  
osg::Image\* imageNegY = osgDB::readImageFile(CUBEMAP\_FILENAME(right));  
osg::Image\* imagePosZ = osgDB::readImageFile(CUBEMAP\_FILENAME(up));  
osg::Image\* imageNegZ = osgDB::readImageFile(CUBEMAP\_FILENAME(back));

if (imagePosX && imageNegX && imagePosY /\*&& imageNegY && imagePosZ && imageNegZ\*/)  
\{  
   cubemap->setImage(osg::TextureCubeMap::POSITIVE\_X, imagePosX);  
   cubemap->setImage(osg::TextureCubeMap::NEGATIVE\_X, imageNegX);  
   cubemap->setImage(osg::TextureCubeMap::POSITIVE\_Y, imagePosY);  
   cubemap->setImage(osg::TextureCubeMap::NEGATIVE\_Y, imageNegY);  
   cubemap->setImage(osg::TextureCubeMap::POSITIVE\_Z, imagePosZ);  
   cubemap->setImage(osg::TextureCubeMap::NEGATIVE\_Z, imageNegZ);

cubemap->setWrap(osg::Texture::WRAP\_S, osg::Texture::CLAMP\_TO\_EDGE);  
   cubemap->setWrap(osg::Texture::WRAP\_T, osg::Texture::CLAMP\_TO\_EDGE);  
   cubemap->setWrap(osg::Texture::WRAP\_R, osg::Texture::CLAMP\_TO\_EDGE);

cubemap->setFilter(osg::Texture::MIN\_FILTER, osg::Texture::LINEAR\_MIPMAP\_LINEAR);  
   cubemap->setFilter(osg::Texture::MAG\_FILTER, osg::Texture::LINEAR);  
\}

return cubemap;  
\}

// Update texture matrix for cubemaps  
struct TexMatCallback : public osg::NodeCallback  
\{  
public:

TexMatCallback(osg::TexMat& tm) :  
    \_texMat(tm)  
    \{  
    \}

virtual void operator()(osg::Node\* node, osg::NodeVisitor\* nv)  
    \{  
     osgUtil::CullVisitor\* cv = dynamic\_cast<osgUtil::CullVisitor\*>(nv);  
     if (cv)  
     \{  
      const osg::Matrix& MV = cv->getModelViewMatrix();  
      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);

osg::Quat q = MV.getRotate();  
      const osg::Matrix C = osg::Matrix::rotate( q.inverse() );

\_texMat.setMatrix( C\*R );  
     \}

traverse(node,nv);  
    \}

osg::TexMat& \_texMat;  
\};

class MoveEarthySkyWithEyePointTransform : public osg::Transform  
\{  
public:  
/\*\* Get the transformation matrix which moves from local coords to world coords.\*/  
virtual bool computeLocalToWorldMatrix(osg::Matrix& matrix,osg::NodeVisitor\* nv) const  
\{  
   osgUtil::CullVisitor\* cv = dynamic\_cast<osgUtil::CullVisitor\*>(nv);  
   if (cv)  
   \{  
    osg::Vec3 eyePointLocal = cv->getEyeLocal();  
    matrix.preMult(osg::Matrix::translate(eyePointLocal));  
   \}  
   return true;  
\}

/\*\* Get the transformation matrix which moves from world coords to local coords.\*/  
virtual bool computeWorldToLocalMatrix(osg::Matrix& matrix,osg::NodeVisitor\* nv) const  
\{  
   osgUtil::CullVisitor\* cv = dynamic\_cast<osgUtil::CullVisitor\*>(nv);  
   if (cv)  
   \{  
    osg::Vec3 eyePointLocal = cv->getEyeLocal();  
    matrix.postMult(osg::Matrix::translate(-eyePointLocal));  
   \}  
   return true;  
\}  
\};

osg::Node\* createSkyBox()  
\{

osg::StateSet\* stateset = new osg::StateSet();

osg::TexEnv\* te = new osg::TexEnv;  
te->setMode(osg::TexEnv::REPLACE);  
stateset->setTextureAttributeAndModes(0, te, osg::StateAttribute::ON);

osg::TexGen \*tg = new osg::TexGen;  
tg->setMode(osg::TexGen::NORMAL\_MAP);  
stateset->setTextureAttributeAndModes(0, tg, osg::StateAttribute::ON);

osg::TexMat \*tm = new osg::TexMat;  
stateset->setTextureAttribute(0, tm);

osg::TextureCubeMap\* skymap = readCubeMap();  
stateset->setTextureAttributeAndModes(0, skymap, osg::StateAttribute::ON);

stateset->setMode( GL\_LIGHTING, osg::StateAttribute::OFF );  
stateset->setMode( GL\_CULL\_FACE, osg::StateAttribute::OFF );

// clear the depth to the far plane.  
osg::Depth\* depth = new osg::Depth;  
depth->setFunction(osg::Depth::ALWAYS);  
depth->setRange(1.0,1.0);     
stateset->setAttributeAndModes(depth, osg::StateAttribute::ON );

stateset->setRenderBinDetails(-1,"RenderBin");

osg::Drawable\* drawable = new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0f,0.0f,0.0f),1));

osg::Geode\* geode = new osg::Geode;  
geode->setCullingActive(false);  
geode->setStateSet( stateset );  
geode->addDrawable(drawable);

osg::Transform\* transform = new MoveEarthySkyWithEyePointTransform;  
transform->setCullingActive(false);  
transform->addChild(geode);

osg::ClearNode\* clearNode = new osg::ClearNode;  
//   clearNode->setRequiresClear(false);  
clearNode->setCullCallback(new TexMatCallback(\*tm));  
clearNode->addChild(transform);

return clearNode;  
\}

[http_hi.baidu.com_janxhuilk_blog_item_7a16871b2bd941fbae5133af.html_cmtid_eb8393b4a19d267b8ad4b217]: http://hi.baidu.com/janxhuilk/blog/item/7a16871b2bd941fbae5133af.html/cmtid/eb8393b4a19d267b8ad4b217