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'''OpenGL extension DFX.multisample |
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This module customises the behaviour of the |
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OpenGL.raw.GL.DFX.multisample 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 provides a mechanism to antialias all GL primitives: |
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points, lines, polygons, bitmaps, and images. The technique is to |
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sample all primitives multiple times at each pixel. The color sample |
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values are resolved to a single, displayable color each time a pixel |
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is updated, so the antialiasing appears to be automatic at the |
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application level. Because each sample includes depth and stencil |
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information, the depth and stencil functions perform equivalently to |
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the single-sample mode. |
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An additional buffer, called the multisample buffer, is added to the |
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framebuffer. Pixel sample values, including color, depth, and |
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stencil values, are stored in this buffer. When the framebuffer |
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includes a multisample buffer, it does not also include separate |
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depth or stencil buffers, even if the multisample buffer does not |
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store depth or stencil values. Color buffers (left/right, |
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front/back, and aux) do coexist with the multisample buffer, |
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however. |
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Multisample antialiasing is most valuable for rendering polygons, |
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because it requires no sorting for hidden surface elimination, and |
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it correctly handles adjacent polygons, object silhouettes, and even |
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intersecting polygons. If only points or lines are being rendered, |
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the "smooth" antialiasing mechanism provided by the base GL may |
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result in a higher quality image. |
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This extension is a subset of SGIS_multisample. It differs in these |
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key ways: |
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* Fragment alpha values are not affected by the fragment sample mask |
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* The sample locations may or may not be fixed. Thus, there is no |
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support for rendering the scene multiple times with different |
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sample points. |
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* Fragment masks are not computed for images or for bitmasks. |
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Because of these differences a new extension was created. However, |
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it is not expected that this extension will co-exist with |
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SGIS_multisample. Because of this and the fact that there are only |
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32 push/pop bits the MULTISAMPLE_BIT_SGIS state value is the same as |
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MUTLISAMPLE_BIT_3DFX. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/DFX/multisample.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.DFX.multisample import * |
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from OpenGL.raw.GL.DFX.multisample import _EXTENSION_NAME |
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def glInitMultisampleDFX(): |
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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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