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'''OpenGL extension SGIX.fog_offset |
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This module customises the behaviour of the |
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OpenGL.raw.GL.SGIX.fog_offset 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 allows fragments to look brighter in a foggy |
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environment, by biasing the fragment eye-coordinate distance prior |
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to fog computation. A reference point in eye space (rx ry rz) and an offset |
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amount toward the viewpoint (f_o) are specified. When fog offset is |
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enabled, the offset amount will be subtracted from the fragment |
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distance, making objects appear less foggy. |
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If fog computation is done in screen-space coordinates under |
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perspective projection, the reference point is used in adjusting the |
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fog offset to be correct for fragments whose depth is close to that |
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point. The reference point should be redefined when it becomes too |
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far away from the primitives being drawn. Under orthographic |
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projection, or if fog computation is done in eye-space coordinates, |
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the reference point is ignored. |
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The official definition of this extension is available here: |
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http://www.opengl.org/registry/specs/SGIX/fog_offset.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.fog_offset import * |
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from OpenGL.raw.GL.SGIX.fog_offset import _EXTENSION_NAME |
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def glInitFogOffsetSGIX(): |
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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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