|
|
'''OpenGL extension OML.subsample |
|
|
|
|
|
This module customises the behaviour of the |
|
|
OpenGL.raw.GL.OML.subsample to provide a more |
|
|
Python-friendly API |
|
|
|
|
|
Overview (from the spec) |
|
|
|
|
|
Many video image formats and compression techniques utilize various |
|
|
component subsamplings, so it is necessary to provide a mechanism to |
|
|
specify the up- and down-sampling of components as pixel data is |
|
|
drawn from and read back to the client. Though subsampled components |
|
|
are normally associated with the video color space, YCrCb, use of |
|
|
subsampling in OpenGL does not imply a specific color space. Color |
|
|
space conversion may be performed using other extensions or core |
|
|
capabilities such as the color matrix. |
|
|
|
|
|
This extension defines two new pixel storage formats representing |
|
|
subsampled data on the client. It is loosely based on the |
|
|
SGIX_subsample extension, but specifies subsampling with the data |
|
|
format parameter rather than pixel packing parameters. It also |
|
|
adds support for CYA subsampled data. |
|
|
|
|
|
When pixel data is received from the client and an unpacking |
|
|
upsampling mode other than PIXEL_SUBSAMPLE_NONE_OML is specified, |
|
|
upsampling is performed via replication, unless otherwise specified |
|
|
by UNPACK_RESAMPLE_OML. |
|
|
|
|
|
Similarly, when pixel data is read back to the client and a packing |
|
|
downsampling mode other than PIXEL_SUBSAMPLE_NONE_OML is specified, |
|
|
downsampling is performed via simple component decimation (point |
|
|
sampling), unless otherwise specified by PACK_RESAMPLE_OML. |
|
|
|
|
|
The official definition of this extension is available here: |
|
|
http://www.opengl.org/registry/specs/OML/subsample.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.OML.subsample import * |
|
|
from OpenGL.raw.GL.OML.subsample import _EXTENSION_NAME |
|
|
|
|
|
def glInitSubsampleOML(): |
|
|
'''Return boolean indicating whether this extension is available''' |
|
|
from OpenGL import extensions |
|
|
return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
|
|
|
|
|
|
|
|
|
|
from OpenGL import images as _i |
|
|
_i.COMPONENT_COUNTS[ GL_FORMAT_SUBSAMPLE_24_24_OML ] = 1 |
|
|
_i.COMPONENT_COUNTS[ GL_FORMAT_SUBSAMPLE_244_244_OML ] = 1 |
|
|
|
