| '''OpenGL extension SGIX.subsample |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GL.SGIX.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. |
| |
| This extension defines new pixel storage modes that are used in |
| the conversion of image data to and from component subsampled |
| formats on the client side. The extension defines a new pixel |
| storage mode to specify these sampling patterns, there are |
| three legal values (PIXEL_SUBSAMPLE_4444_SGIX, |
| PIXEL_SUBSAMPLE_4242_SGIX, and |
| PIXEL_SUBSAMPLE_2424_SGIX). |
| |
| When pixel data is received from the client and an unpacking |
| upsampling mode other than PIXEL_SUBSAMPLE_4444_SGIX is |
| specified, the upsampling is performed via replication, |
| unless otherwise specified by RESAMPLE_SGIX. |
| |
| Similarly, when pixel data is read back to the client and a |
| packing downsampling mode other than |
| PIXEL_SUBSAMPLE_4444_SGIX is specified, downsampling is |
| performed via simple component decimation (point sampling), |
| unless otherwise specified by RESAMPLE_SGIX. |
| |
| The official definition of this extension is available here: |
| http://www.opengl.org/registry/specs/SGIX/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.SGIX.subsample import * |
| from OpenGL.raw.GL.SGIX.subsample import _EXTENSION_NAME |
|
|
| def glInitSubsampleSGIX(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
|
|
|
| |
