Hi Robert,
In the cow.osg model, they use SPHERE_MAP to generate the texture coordinates.
I wonder whether openscenegraph has the same kinds of functions. Would you
please tell me?
Thanks,
Ying
robertosfield wrote:
> Hi Ying,
>
> The cow.osg model uses osg::TexGen (wrapper for glTexGen) to generate the
> texture coordinates so the ones assigned to actual geometry are ignored.
> glTexGen is part of the fixed function pipeline in OpenGL so you don't get
> this functionality when using shaders. You'll have to implement your own
> texgen to generate the texture coordinates for this model, or apply your own.
>
>
> Might I suggest using other models that do have appropriate texture
> coordinate on them for testing.
>
>
> Robert.
>
>
>
> On 6 August 2014 15:52, ying song < ()> wrote:
>
> > Hello Robert,
> >
> > Yes, you are right. The reason is that I didn't set up the texture
> > coordinates. I did the following change, and I could texturing the model in
> > the shader. I think the problem is that gl_MultiTexCoord0 actually didn't
> > give out any texture coordinates in my first code.
> >
> > vertex shader:
> > varying vec2 texCoord;
> > void main()
> > {
> >
> > gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
> >
> > texCoord = gl_Vertex.xy;
> > }
> >
> > fragment shader:
> > uniform sampler2D texture;
> > varying vec2 texCoord ;
> > void main()
> > {
> > vec4 color = texture2D(texture, texCoord );
> > gl_FragColor = color;
> > }
> >
> > But in this way, I set the texture coordinate according to gl_Vertex, which
> > is still not what I wanted.
> >
> > If I want to render the cow.osg model using shaders, how could I get the
> > texture coordinates from the osg file? I checked the original osg file of
> > the cow model, and found that the texture coordinates are all set to (0,0)
> > in this file. I wonder whether it's necessary to use texture coordinates if
> > I want to render the cow model.
> >
> > If I want to render the exact same cow model using shaders, would you tell
> > me how could I do it?
> >
> > Thanks,
> > Ying
> >
> > robertosfield wrote:
> >
> > > Hi Ying,
> > >
> > > It's not possible to pinpoint what is wrong as you provide no guidance of
> > > how you set up your osg::Geometry. My best guess would be that you don't
> > > set up the texture coordinates.
> > >
> > >
> > > Have a look at the osgshaders example for inspiration,
> > >
> > >
> > > Robert.
> > >
> > >
> > >
> > >
> >
> >
> > > On 5 August 2014 16:31, ying song < ()> wrote:
> > >
> > >
> > > > Hello everyone,
> > > >
> > > > I tried texturing a cube by using shaders, but failed. I already tried
> > > > all the way I could think about, but the rendered cube is still totally
> > > > black if I use shaders. Could someone help me on this?
> > > >
> > > > Here is mycode:
> > > > cpp file:
> > > > osg::ref_ptr<osg::Image> image =
> > > > osgDB::readImageFile("Images/reflect.rgb");
> > > > osg::ref_ptr<osg::Node> node = createNode(); //create the cube
> > > >
> > > > osg::StateSet* squareState = node->getOrCreateStateSet();
> > > > osg::Program* squareProgramObject = new osg::Program;
> > > > osg::Shader* squareVertexObject = new osg::Shader(
> > > > osg::Shader::VERTEX );
> > > > osg::Shader* squareFragmentObject = new osg::Shader(
> > > > osg::Shader::FRAGMENT );
> > > > squareProgramObject->addShader( squareFragmentObject );
> > > > squareProgramObject->addShader( squareVertexObject );
> > > > squareVertexObject->loadShaderSourceFromFile(
> > > > "shaders/cubeRender.vert");
> > > >
> > > > squareFragmentObject->loadShaderSourceFromFile("shaders/cubeRender.frag");
> > > > squareState->setAttributeAndModes(squareProgramObject,
> > > > osg::StateAttribute::ON);
> > > >
> > > > osg::ref_ptr<osg::Texture2D> texture = new osg::Texture2D();
> > > > texture->setImage(image.get());
> > > >
> > > > texture->setFilter(osg::Texture::MIN_FILTER,osg::Texture::NEAREST_MIPMAP_NEAREST);
> > > > //choose the nearest texture unit value
> > > >
> > > > texture->setFilter(osg::Texture::MAG_FILTER,osg::Texture::LINEAR);
> > > > //choose the average of the nearest 4 pixel values as texture
> > > >
> > > > osg::Uniform* myTextureU = new
> > > > osg::Uniform("myTexture",texture.get());
> > > > squareState->addUniform(myTextureU);
> > > >
> > > > viewer->setSceneData(node.get());
> > > >
> > > > vertex shader:
> > > >
> > > > void main()
> > > > {
> > > >
> > > > gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
> > > > gl_TexCoord[0] = gl_MultiTexCoord0;
> > > > }
> > > >
> > > > fragment shader:
> > > > uniform sampler2D myTexture;
> > > >
> > > > void main()
> > > > {
> > > > vec4 color = texture2D(myTexture, gl_TexCoord[0].st);
> > > > gl_FragColor = color;
> > > > }
> > > >
> > > > Thanks a lot!
> > > >
> > > > Cheers,
> > > > ying[/b]
> > > >
> > > > ------------------
> > > > Read this topic online here:
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> > > > http://forum.openscenegraph.org/viewtopic.php?p=60539#60539
> > > > (http://forum.openscenegraph.org/viewtopic.php?p=60539#60539)
> > > > (http://forum.openscenegraph.org/viewtopic.php?p=60539#60539
> > > > (http://forum.openscenegraph.org/viewtopic.php?p=60539#60539))
> > > >
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> > > >
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