| '''OpenGL extension SGIX.texture_lod_bias |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GL.SGIX.texture_lod_bias to provide a more |
| Python-friendly API |
| |
| Overview (from the spec) |
| |
| This extension modifies the calculation of texture level of detail |
| parameter LOD, which is represented by the Greek character lambda |
| in the GL Specification. The LOD equation assumes that a 2^n x 2^m x 2^l |
| texture is band limited at 2^(n-1), 2^(m-1), 2^(l-1). Often a texture is |
| oversampled or filtered such that the texture is band limited at lower |
| frequencies in one or more dimensions. The result is that texture-mapped |
| primitives appear excessively blurry. This extension provides biases |
| for n, m, and l in the LOD calculation to to compensate for under or over |
| sampled texture images. Mipmapped textures can be made to appear sharper or |
| blurrier by supplying a negative or positive bias respectively. |
| |
| Examples of textures which can benefit from this LOD control include |
| video-capture images which are filtered differently horizontally and |
| vertically; a texture which appears blurry because it is mapped with |
| a nonuniform scale, such as a road texture which is repeated hundreds of |
| times in one dimension and only once in the other; and textures which |
| had to be magnified to a power-of-two for mipmapping. |
| |
| The official definition of this extension is available here: |
| http://www.opengl.org/registry/specs/SGIX/texture_lod_bias.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.SGIX.texture_lod_bias import * |
| from OpenGL.raw.GL.SGIX.texture_lod_bias import _EXTENSION_NAME |
|
|
| def glInitTextureLodBiasSGIX(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
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| |
