OpenGL.GL.NV.texgen_emboss

OpenGL extension NV.texgen_emboss

This module customises the behaviour of the OpenGL.raw.GL.NV.texgen_emboss to provide a more Python-friendly API

Overview (from the spec)

This extension provides a new texture coordinate generation mode suitable for multitexture-based embossing (or bump mapping) effects.

Given two texture units, this extension generates the texture coordinates of a second texture unit (an odd-numbered texture unit) as a perturbation of a first texture unit (an even-numbered texture unit one less than the second texture unit). The perturbation is based on the normal, tangent, and light vectors. The normal vector is supplied by glNormal; the light vector is supplied as a direction vector to a specified OpenGL light's position; and the tanget vector is supplied by the second texture unit's current texture coordinate. The perturbation is also scaled by program-supplied scaling constants.

If both texture units are bound to the same texture representing a height field, by subtracting the difference between the resulting two filtered texels, programs can achieve a per-pixel embossing effect.

The official definition of this extension is available here: http://www.opengl.org/registry/specs/NV/texgen_emboss.txt