[osg-users] texture to shader parameter?

[Nan WANG]

Hello everyone:

i have a question regarding how to pass texture to shader 

There were some code in the tutorial, such as:


Code:

      bumpMapProgramObject->addShader( bumpFragmentObject );
       bumpMapProgramObject->addShader( bumpVertexObject );

       osg::Uniform* lightPosU = 
          new osg::Uniform("LightPosition",osg::Vec3(0,0,1));
       osg::Uniform* normalMapU = new osg::Uniform("normalMap",1);
       osg::Uniform* baseTextureU = new osg::Uniform("baseTexture",0);

       bumpMapState->addUniform(lightPosU);
       bumpMapState->addUniform(normalMapU);
       bumpMapState->addUniform(baseTextureU);
       lightPosU->setUpdateCallback(new updateBumpShader() );

       bumpMapState->setAttributeAndModes
          (bumpMapProgramObject, osg::StateAttribute::ON);

       osg::Texture2D* tankBodyNormalMap = new osg::Texture2D;
       tankBodyNormalMap->setDataVariance(osg::Object::DYNAMIC); 
       osg::Image* tankBody = osgDB::readImageFile("TankBump.png");
       if (!tankBody)
       {
          std::cout << " couldn't find texture, quiting." << std::endl;
          return -1;
       }

       tankBodyNormalMap->setImage(tankBody);
       bumpMapState->setTextureAttributeAndModes
          (1,tankBodyNormalMap,osg::StateAttribute::ON);




Here, the example creates
 osg::Uniform* normalMapU = new osg::Uniform("normalMap",1);

'1'is the initial value of normalMap? how to link to texture unit in shader?

using (Am I right?)

       bumpMapState->setTextureAttributeAndModes
(1,tankBodyNormalMap,osg::StateAttribute::ON);


here the value of first parameter should be the same as initial value in the 
'new osg::Uniform("normalMap",1);'

and the way to have the 'tankBodyNormalMap' in bumpmap.vert, using 
gl_MultiTexCoord0 or gl_MultiTexCoord1?

where we can find  bumpmap.vert?

Thank you!

Cheers,
Nan

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=38982#38982





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