OpenGL.GL.NV.register_combiners2

OpenGL extension NV.register_combiners2

This module customises the behaviour of the OpenGL.raw.GL.NV.register_combiners2 to provide a more Python-friendly API

Overview (from the spec)

The NV_register_combiners extension provides a powerful fragment coloring mechanism. This specification extends the register combiners functionality to support more color constant values that are unique for each general combiner stage.

The base register combiners functionality supports only two color constants. These two constants are available in every general combiner stage and in the final combiner.

When many general combiner stages are supported, more than two unique color constants is often required. The obvious way to extend the register combiners is to add several more color constant registers. But adding new unique color constant registers is expensive for hardware implementation because every color constant register must be available as an input to any stage.

In practice however, it is the total set of general combiner stages that requires more color constants, not each and every individual general combiner stage. Each individual general combiner stage typically requires only one or two color constants.

By keeping two color constant registers but making these two registers contain two unique color constant values for each general combiner stage, the hardware expense of supporting multiple color constants is minimized. Additionally, this scheme scales appropriately as more general combiner stages are added.

The official definition of this extension is available here: http://www.opengl.org/registry/specs/NV/register_combiners2.txt