Andrea,
The vertex color is available in the vertex shader as gl_Color. Pass this
to your fragment shader in a varying and apply it there.
Glenn Waldron / @glennwaldron
On Wed, Jan 30, 2013 at 5:23 AM, Andrea Martini <martini.and...@gmail.com>wrote:
> Hi,
>
> i'm wondering if it is possible to keep original materials and colors of a
> 3D model, even if we want to apply some shaders effect. In detail, i have a
> 3D model that appears as attached figure (original 3d model with color -
> objectwithcolor.png) without any shaders applied.
> If i apply some shaders effect, i loose colors from my model (figure
> with shaders applied - objectWithShader.png)
> Here i report the simple code :
>
> int main( int argc, char** argv )
> {
>
> osg::ref_ptr<osg::Node> root = osgDB::readNodeFiles( arguments );
> if ( !root ) root = osgDB::readNodeFile("myModel.osg");
>
> osg::ref_ptr<osg::Program> program =new osg::Program;
>
> osgViewer::Viewer viewer;
>
>
> // Shaders effect
> osg::Shader* vertexShader = osgDB::readShaderFile(osg::Shader::VERTEX,
> "dynamic.vert");
>
> if (!vertexShader)
> {
> std::cout << " No vertex Shader Loaded." << std::endl;
> return 0;
> }
>
> osg::Shader* fragShader = osgDB::readShaderFile(osg::Shader::FRAGMENT,
> "dynamic.frag");
>
> if (!fragShader)
> {
> std::cout << " No fragment Shader Loaded." << std::endl;
> return 0;
> }
>
> program->addShader(vertexShader);
> program->addShader(fragShader);
>
> osg::StateSet* stateset = root->getOrCreateStateSet();
>
> stateset->setAttributeAndModes( program.get());
>
> stateset->addUniform( new osg::Uniform("lightDiffuse", osg::Vec4(0.8f,
> 0.8f, 0.8f, 1.0f)) );
>
> stateset->addUniform( new osg::Uniform("lightSpecular", osg::Vec4(1.0f,
> 1.0f, 0.4f, 1.0f)) );
>
> stateset->addUniform( new osg::Uniform("shininess", 64.0f) );
>
> osg::ref_ptr<osg::Uniform> lightPos = new osg::Uniform( "lightPosition",
> osg::Vec3() );
>
> lightPos->setUpdateCallback( new LightPosCallback );
> stateset->addUniform( lightPos.get() );
>
>
> viewer.setSceneData( root.get() );
> viewer.setUpViewInWindow( 100, 100, 800, 600 );
>
> viewer.run();
>
>
> return 0;
> }
>
> Now the vertex and fragment code :
>
> //dynamic.vert
>
> uniform vec3 lightPosition;
> varying vec3 normal, eyeVec, lightDir;
>
> void main()
> {
> vec4 vertexInEye = gl_ModelViewMatrix * gl_Vertex;
> eyeVec = -vertexInEye.xyz;
> lightDir = vec3(lightPosition - vertexInEye.xyz);
> normal = gl_NormalMatrix * gl_Normal;
> gl_Position = ftransform();
> }
>
>
> //dynamic.frag
>
> uniform vec4 lightDiffuse;
> uniform vec4 lightSpecular;
> uniform float shininess;
> varying vec3 normal, eyeVec, lightDir;
> void main (void)
> {
> vec4 finalColor = gl_FrontLightModelProduct.sceneColor;
> vec3 N = normalize(normal);
> vec3 L = normalize(lightDir);
> float lambert = dot(N,L);
> if (lambert > 0.0)
> {
> finalColor += lightDiffuse * lambert;
> vec3 E = normalize(eyeVec);
> vec3 R = reflect(-L, N);
> float specular = pow(max(dot(R, E), 0.0), shininess);
> finalColor += lightSpecular * specular;
> }
> gl_FragColor = finalColor;
> }
>
>
>
> Thank you!
>
> Cheers,
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=52273#52273
>
>
>
>
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>
>
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