GLSL equivalent of OpenGL texturing

Hi, Folks,

I'm new to shaders and to this forum, so forgive me if this topic has been discussed before. I would like to create a shader that does nothing more than turning the basic GL lighting into per pixel lighting, while preserving all other functionalities. Hence comes the question: my scene contains geometry loaded from files such as OpenFlight models, where different faces may use different lighting and texturing methods, which I assume I'll need to replicate in the shader. So, for each fragment I'll need knowledge of the following:

1. Is the fragment lit?
2. Does it use texture?
3. How is the texture and the material combined, GL_REPLACE, GL_MODULATE, or GL_DECAL?
4. Is it multi-textured?

I can live with the assumption that there's no multitexturing for now, I may even get away with assuming it's always GL_MODULATE when there's texture, but I must know 1 and 2. The various shader tutorials I have read all assume the user knows the texturing method to be used in advance, and it is not clear to me if there are any built-in constants or variables that tells if lighting is turned on for a fragment, if texture is used, and how it is combined with the base material.


This topic was automatically closed 183 days after the last reply. New replies are no longer allowed.