OpenGL extension AMD.vertex_shader_viewport_index
This module customises the behaviour of the OpenGL.raw.GL.AMD.vertex_shader_viewport_index to provide a more Python-friendly API
Overview (from the spec)
The gl_ViewportIndex built-in variable was introduced by the ARB_viewport_array extension and OpenGL 4.1. This variable is available in un-extended OpenGL only to the geometry shader. When written in the geometry shader, it causes geometry to be directed to one of an array of several independent viewport rectangles.
In order to use any viewport other than zero, a geometry shader must be present. Geometry shaders introduce processing overhead and potential performance issues. This extension exposes the gl_ViewportIndex built-in variable to the vertex shader, allowing the functionality introduced by ARB_viewport_array to be accessed without requiring a geometry shader to be present.
The official definition of this extension is available here:
Return boolean indicating whether this extension is available