OpenGL.GL.ARB.instanced_arrays

OpenGL extension ARB.instanced_arrays

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

Overview (from the spec)

A common use case in GL for some applications is to be able to draw the same object, or groups of similar objects that share vertex data, primitive count and type, multiple times. This extension provides a means of accelerating such use cases while restricting the number of API calls, and keeping the amount of duplicate data to a minimum.

In particular, this extension specifies an alternative to the read-only shader variable introduced by ARB_draw_instanced. It uses the same draw calls introduced by that extension, but redefines them so that a vertex shader can instead use vertex array attributes as a source of instance data.

This extension introduces an array "divisor" for generic vertex array attributes, which when non-zero specifies that the attribute is "instanced." An instanced attribute does not advance per-vertex as usual, but rather after every <divisor> conceptual draw calls.

(Attributes which aren't instanced are repeated in their entirety for every conceptual draw call.)

By specifying transform data in an instanced attribute or series of instanced attributes, vertex shaders can, in concert with the instancing draw calls, draw multiple instances of an object with one draw call.

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