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'''OpenGL extension SGIX.subsample |
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This module customises the behaviour of the |
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OpenGL.raw.GL.SGIX.subsample to provide a more |
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Python-friendly API |
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Overview (from the spec) |
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Many video image formats and compression techniques utilize |
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various component subsamplings, so it is necessary to provide a |
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mechanism to specify the up- and down-sampling of components as |
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pixel data is drawn from and read back to the client. Though |
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subsampled components are normally associated with the video |
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color space, YCrCb, use of subsampling in OpenGL does not imply |
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a specific color space. |
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This extension defines new pixel storage modes that are used in |
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the conversion of image data to and from component subsampled |
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formats on the client side. The extension defines a new pixel |
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storage mode to specify these sampling patterns, there are |
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three legal values (PIXEL_SUBSAMPLE_4444_SGIX, |
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PIXEL_SUBSAMPLE_4242_SGIX, and |
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PIXEL_SUBSAMPLE_2424_SGIX). |
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When pixel data is received from the client and an unpacking |
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upsampling mode other than PIXEL_SUBSAMPLE_4444_SGIX is |
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specified, the upsampling is performed via replication, |
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unless otherwise specified by RESAMPLE_SGIX. |
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Similarly, when pixel data is read back to the client and a |
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packing downsampling mode other than |
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PIXEL_SUBSAMPLE_4444_SGIX is specified, downsampling is |
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performed via simple component decimation (point sampling), |
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unless otherwise specified by RESAMPLE_SGIX. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/SGIX/subsample.txt |
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''' |
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from OpenGL import platform, constant, arrays |
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from OpenGL import extensions, wrapper |
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import ctypes |
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from OpenGL.raw.GL import _types, _glgets |
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from OpenGL.raw.GL.SGIX.subsample import * |
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from OpenGL.raw.GL.SGIX.subsample import _EXTENSION_NAME |
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def glInitSubsampleSGIX(): |
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'''Return boolean indicating whether this extension is available''' |
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from OpenGL import extensions |
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return extensions.hasGLExtension( _EXTENSION_NAME ) |
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