[osg-users] OpenGL ES 2.0 and LIGHTING

[Grigoriy Mylnikov]

Sorry for delayed reply.

My goal is to open and display .osgt files on android the same way they can be opened on desktop. This includes using several lights inside a model, both directional and point lights.

I have some progress with writing shaders, but I have troubles with understanding OSG states. I've updated osg::Light apply() code to pass light position (relative to camera) as uniform:


Code:
void LightShader::apply(osg::State& state) const
{
#ifdef OSG_GL_FIXED_FUNCTION_AVAILABLE
... // Original code
#else
    ...
    osg::Vec4 relPos = state.getModelViewMatrix() * _position;
    lightPosUniform.get()->set(relPos);
    ...
#endif
}




But it seems that state.getModelViewMatrix() does not gives me valid view matrix.

If I could get light position (relative to camera), I can use it in shaders like this:


Code:
vec3 APos = vec3(gl_ModelViewMatrix * gl_Vertex);
...
vec3 fromPointToLight = lightPos.xyz - APos;




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