OpenGL extension SGIX.reference_plane
This module customises the behaviour of the OpenGL.raw.GL.SGIX.reference_plane to provide a more Python-friendly API
Overview (from the spec)
This extension allows a group of coplanar primitives to be rendered without depth-buffering artifacts. This is accomplished by generating the depth values for all the primitives from a single ``reference plane'' rather than from the primitives themselves. This ensures that all the primitives in the group have exactly the same depth value at any given sample point, no matter what imprecision may exist in the original specifications of the primitives or in the GL's coordinate transformation process.
The reference plane is defined by a four-component plane equation. When glReferencePlaneSGIX is called, equation is transformed by the transpose-adjoint of a matrix that is the complete object-coordinate to clip-coordinate transformation. The resulting clip-coordinate coefficients are transformed by the current viewport when the reference plane is enabled.
The reference plane is enabled and disabled with glEnable and glDisable.
If the reference plane is enabled, a fragment (xf,yf,zf) will have a new z coordinate generated from (xf,yf) by giving it the same z value that the reference plane would have at (xf,yf).
The official definition of this extension is available here:
Return boolean indicating whether this extension is available