1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
'''OpenGL extension EXT.pvrtc_sRGB
This module customises the behaviour of the
OpenGL.raw.GLES2.EXT.pvrtc_sRGB to provide a more
Python-friendly API
Overview (from the spec)
The response from electronic display systems given RGB tristimulus values
for each pixel is non-linear. Gamma correction is the process of encoding
or decoding images in a manner that will correct for non-linear response
profiles of output devices. The displayed results of gamma-corrected pixel
data are more consistent and predictable for the author of such pixel data
than it would otherwise be with linearly encoded pixel data.
This EXT_pvrtc_sRGB extension specifies additional tokens for gamma
corrected PVRTC compressed sRGB data.
Texture assets are developed and evaluated for use in OpenGL applications
using electronic displays with non-linear responses. This extension
provides a better measure of consistency between textures developed within
an asset toolchain and their final rendered result with an OpenGL
application that uses those textures.
Conventional OpenGL texture tristimulus values as well as their alpha
component are encoded linearly. The textures introduced by this extension
are encoded with gamma correction in the tristimulus components but
linearly in the alpha component.
When gamma corrected texture samples are fetched and operated on by ALU
operations in an OpenGL shading program those samples will be converted
from gamma corrected space to linear space for logical simplicity and
performance of the shader.
Texture filtering operations as well as mipmap generation are carried out
in linear space.
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/EXT/pvrtc_sRGB.txt
'''
from OpenGL import platform, constant, arrays
from OpenGL import extensions, wrapper
import ctypes
from OpenGL.raw.GLES2 import _types, _glgets
from OpenGL.raw.GLES2.EXT.pvrtc_sRGB import *
from OpenGL.raw.GLES2.EXT.pvrtc_sRGB import _EXTENSION_NAME
def glInitPvrtcSrgbEXT():
'''Return boolean indicating whether this extension is available'''
from OpenGL import extensions
return extensions.hasGLExtension( _EXTENSION_NAME )
### END AUTOGENERATED SECTION
|
