OpenGL extension EXT.texture_filter_anisotropic
This module customises the behaviour of the
OpenGL.raw.GL.EXT.texture_filter_anisotropic to provide a more
Overview (from the spec)
Texture mapping using OpenGL's existing mipmap texture filtering
modes assumes that the projection of the pixel filter footprint into
texture space is a square (ie, isotropic). In practice however, the
footprint may be long and narrow (ie, anisotropic). Consequently,
mipmap filtering severely blurs images on surfaces angled obliquely
away from the viewer.
Several approaches exist for improving texture sampling by accounting
for the anisotropic nature of the pixel filter footprint into texture
space. This extension provides a general mechanism for supporting
anisotropic texturing filtering schemes without specifying a
particular formulation of anisotropic filtering.
The extension permits the OpenGL application to specify on
a per-texture object basis the maximum degree of anisotropy to
account for in texture filtering.
Increasing a texture object's maximum degree of anisotropy may
improve texture filtering but may also significantly reduce the
implementation's texture filtering rate. Implementations are free
to clamp the specified degree of anisotropy to the implementation's
maximum supported degree of anisotropy.
A texture's maximum degree of anisotropy is specified independent
from the texture's minification and magnification filter (as
opposed to being supported as an entirely new filtering mode).
Implementations are free to use the specified minification and
magnification filter to select a particular anisotropic texture
filtering scheme. For example, a NEAREST filter with a maximum
degree of anisotropy of two could be treated as a 2-tap filter that
accounts for the direction of anisotropy. Implementations are also
permitted to ignore the minification or magnification filter and
implement the highest quality of anisotropic filtering possible.
Applications seeking the highest quality anisotropic filtering
available are advised to request a LINEAR_MIPMAP_LINEAR minification
filter, a LINEAR magnification filter, and a large maximum degree
The official definition of this extension is available here:
|EXTENSION_NAME = 'GL_EXT_texture_filter_anisotropic'|
GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT = GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT
GL_TEXTURE_MAX_ANISOTROPY_EXT = GL_TEXTURE_MAX_ANISOTROPY_EXT
__file__ = '/home/mcfletch/pylive/OpenGL/GL/EXT/texture_filter_anisotropic.pyc'
__name__ = 'OpenGL.GL.EXT.texture_filter_anisotropic'
__package__ = 'OpenGL.GL.EXT'