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'''OpenGL extension SGIS.texture_lod
Overview (from the spec)
This extension imposes two constraints related to the texture level of
detail parameter LOD, which is represented by the Greek character lambda
in the GL Specification. One constraint clamps LOD to a specified
floating point range. The other limits the selection of mipmap image
arrays to a subset of the arrays that would otherwise be considered.
Together these constraints allow a large texture to be loaded and
used initially at low resolution, and to have its resolution raised
gradually as more resolution is desired or available. Image array
specification is necessarily integral, rather than continuous. By
providing separate, continuous clamping of the LOD parameter, it is
possible to avoid "popping" artifacts when higher resolution images
are provided.
Note: because the shape of the mipmap array is always determined by
the dimensions of the level 0 array, this array must be loaded for
mipmapping to be active. If the level 0 array is specified with a
null image pointer, however, no actual data transfer will take
place. And a sufficiently tuned implementation might not even
allocate space for a level 0 array so specified until true image
data were presented.
The official definition of this extension is available here:
http://oss.sgi.com/projects/ogl-sample/registry/SGIS/texture_lod.txt
Automatically generated by the get_gl_extensions script, do not edit!
'''
from OpenGL import platform, constants, constant, arrays
from OpenGL import extensions
from OpenGL.GL import glget
import ctypes
EXTENSION_NAME = 'GL_SGIS_texture_lod'
GL_TEXTURE_MIN_LOD_SGIS = constant.Constant( 'GL_TEXTURE_MIN_LOD_SGIS', 0x813A )
GL_TEXTURE_MAX_LOD_SGIS = constant.Constant( 'GL_TEXTURE_MAX_LOD_SGIS', 0x813B )
GL_TEXTURE_BASE_LEVEL_SGIS = constant.Constant( 'GL_TEXTURE_BASE_LEVEL_SGIS', 0x813C )
GL_TEXTURE_MAX_LEVEL_SGIS = constant.Constant( 'GL_TEXTURE_MAX_LEVEL_SGIS', 0x813D )
def glInitTextureLodSGIS():
'''Return boolean indicating whether this extension is available'''
return extensions.hasGLExtension( EXTENSION_NAME )
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