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'''OpenGL extension MESA.ycbcr_texture |
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This module customises the behaviour of the |
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OpenGL.raw.GL.MESA.ycbcr_texture to provide a more |
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Python-friendly API |
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Overview (from the spec) |
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This extension supports texture images stored in the YCbCr format. |
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There is no support for converting YCbCr images to RGB or vice versa |
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during pixel transfer. The texture's YCbCr colors are converted to |
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RGB during texture sampling, after-which, all the usual per-fragment |
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operations take place. Only 2D texture images are supported (not |
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glDrawPixels, glReadPixels, etc). |
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A YCbCr pixel (texel) is a 16-bit unsigned short with two components. |
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The first component is luminance (Y). For pixels in even-numbered |
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image columns, the second component is Cb. For pixels in odd-numbered |
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image columns, the second component is Cr. If one were to convert the |
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data to RGB one would need to examine two pixels from columns N and N+1 |
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(where N is even) to deduce the RGB color. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/MESA/ycbcr_texture.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.MESA.ycbcr_texture import * |
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from OpenGL.raw.GL.MESA.ycbcr_texture import _EXTENSION_NAME |
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def glInitYcbcrTextureMESA(): |
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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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