| '''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 |
| ''' |
| from OpenGL import platform, constant, arrays |
| from OpenGL import extensions, wrapper |
| import ctypes |
| from OpenGL.raw.GL import _types, _glgets |
| from OpenGL.raw.GL.WIN.specular_fog import * |
| from OpenGL.raw.GL.WIN.specular_fog import _EXTENSION_NAME |
|
|
| def glInitSpecularFogWIN(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
|
|
|
| |
