OpenGL.GL.SGIS.texture_edge_clamp

OpenGL extension SGIS.texture_edge_clamp

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

Overview (from the spec)

The base OpenGL provides clamping such that the texture coordinates are limited to exactly the range [0,1]. When a texture coordinate is clamped using this algorithm, the texture sampling filter straddles the edge of the texture image, taking 1/2 its sample values from within the texture image, and the other 1/2 from the texture border. It is sometimes desirable to clamp a texture without requiring a border, and without using the constant border color.

This extension defines a new texture clamping algorithm. CLAMP_TO_EDGE_SGIS clamps texture coordinates at all mipmap levels such that the texture filter never samples a border texel. When used with a NEAREST or a LINEAR filter, the color returned when clamping is derived only from texels at the edge of the texture image. When used with FILTER4 filters, the filter operations of CLAMP_TO_EDGE_SGIS are defined but don't result in a nice clamp-to-edge color.

CLAMP_TO_EDGE_SGIS is supported by 1, 2, and 3-dimensional textures only.

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