OpenGL.GL.WIN.specular_fog

OpenGL extension WIN.specular_fog

This module customises the behaviour of the OpenGL.raw.GL.WIN.specular_fog to provide a more Python-friendly API

Overview (from the spec)

Specularly lit textures enhance the realism of a scene greatly. Using the current OpenGL lighting model, one cannot obtain specularly lit textures. This is because in the current OpenGL lighting model lighting is done ahead of texturing and texture-functions such as modulate are inadequate for such a simulation. What needs to be addressed is that, somehow an additional interpolant (specular color of that material) needs to be propagated till that stage of the pipeline where texture-mapping is performed. This interpolant is then added on to the fragment's color resulting from the texturing process before proceeding with the rest of the pipeline.

This can be addressed very easily in software, but hardware is not so malleable. Currently most hardware does not support such a

lighting model. However, some current hardware does support fogging, which takes place in the pipeline after texturing. This hardware assumes that the fog blend factor f is computed per-vertex and interpolates the value across the primitive. The WIN_specular_fog extension enables the use of such existing fog circuitry to obtain specularly lit textures without much performance degradation.

To use it the programmer simply enables the extension with a call to Enable with the appropriate enumerant and sets the fog color to the desired specular color.

The official definition of this extension is available here: http://www.opengl.org/registry/specs/WIN/specular_fog.txt