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'''OpenGL extension WIN.specular_fog |
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This module customises the behaviour of the |
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OpenGL.raw.GL.WIN.specular_fog to provide a more |
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Python-friendly API |
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Overview (from the spec) |
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Specularly lit textures enhance the realism of a scene greatly. |
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Using the current OpenGL lighting model, one cannot obtain specularly lit |
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textures. This is because in the current OpenGL lighting model lighting |
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is done ahead of texturing and texture-functions such as modulate are |
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inadequate for such a simulation. What needs to be addressed is that, |
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somehow an additional interpolant (specular color of that material) needs |
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to be propagated till that stage of the pipeline where texture-mapping is |
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performed. This interpolant is then added on to the fragment's color |
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resulting from the texturing process before proceeding with the rest of |
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the pipeline. |
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This can be addressed very easily in software, but hardware |
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is not so malleable. Currently most hardware does not support such a |
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lighting model. However, some current hardware does support fogging, |
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which takes place in the pipeline after texturing. This hardware |
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assumes that the fog blend factor f is computed per-vertex and |
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interpolates the value across the primitive. The WIN_specular_fog |
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extension enables the use of such existing fog circuitry to obtain |
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specularly lit textures without much performance degradation. |
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To use it the programmer simply enables the extension with a call to |
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Enable with the appropriate enumerant and sets the fog color to the |
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desired specular color. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/WIN/specular_fog.txt |
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''' |
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from OpenGL import platform, constant, arrays |
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from OpenGL import extensions, wrapper |
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import ctypes |
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from OpenGL.raw.GL import _types, _glgets |
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from OpenGL.raw.GL.WIN.specular_fog import * |
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from OpenGL.raw.GL.WIN.specular_fog import _EXTENSION_NAME |
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def glInitSpecularFogWIN(): |
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'''Return boolean indicating whether this extension is available''' |
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from OpenGL import extensions |
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return extensions.hasGLExtension( _EXTENSION_NAME ) |
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