Polygon Offset availability test GLboolean glaf_IsPolygonOffsetSupported(void) This function returns GL_TRUE if the feature is supported or
GL_FALSE
otherwise.
Calling the functions of an unsupported feature or using its enumerants
may crash the application, or generate OpenGL errors, or even undefined
behaviour, so you should never use a feature without testing its availability
first.
Polygon Offset support rules
(Add either a 'GLAF_' or 'GL_' prefix before each enumerant. GLAF enumerants are always defined, while GL ones depend on the version of your include files). POLYGON_OFFSET (for glEnable/glDisable)
Polygon Offset functions glaf_PolygonOffset Beware! Only the GL_FILL mode is supported by GLAF, because there's no way of supporting other modes in OpenGL1.0. Note: The arguments' meaning is always the one
of the core 1.1 polygon offset feature. If we're running in OpenGL 1.0,
GLAF will silently do a conversion of the bias argument. This conversion
is tricky and it's not guaranteed to always give good results, because
the actual significant bits of the depth buffer may not match the value
returned by glGet. For getting the "Z effective unit", GLAF will
discard 4 bits of the depth buffer. This may sound a bit exaggerated, but
it's what SGI implicitly recommends in the glPolygonOffsetEXT manpage
(ie: using 1/2**16 for 20bit Z-buffers and 1/2**20 for 24bit Z-buffers).
Polygon Offset definitions in 'gl2glaf.h' (optional) #define glPolygonOffset
glaf_PolygonOffset
Polygon Offset side effects None.
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Copyright (C) 2001 César Blecua Udías