Native bindings to the ARB_color_buffer_float extension.

The standard OpenGL pipeline is based on a fixed-point pipeline. While color components are nominally floating-point values in the pipeline, components are frequently clamped to the range [0,1] to accomodate the fixed-point color buffer representation and allow for fixed-point computational hardware.

This extension adds pixel formats or visuals with floating-point RGBA color components and controls for clamping of color components within the pipeline.

For a floating-point RGBA pixel format, the size of each float components is specified using the same attributes that are used for defining the size of fixed-point components. 32-bit floating-point components are in the standard IEEE float format. 16-bit floating-point components have 1 sign bit, 5 exponent bits, and 10 mantissa bits.

Clamping control provides a way to disable certain color clamps and allow programs, and the fixed-function pipeline, to deal in unclamped colors. There are controls to modify clamping of vertex colors, clamping of fragment colors throughout the pipeline, and for pixel return data.

The default state for fragment clamping is FIXED_ONLY_ARB, which has the behavior of clamping colors for fixed-point color buffers and not clamping colors for floating-pont color buffers.

Vertex colors are clamped by default.

Promoted to core in OpenGL 3.0.