OpenGL.GL.ARB.program_interface_query

OpenGL extension ARB.program_interface_query

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

Overview (from the spec)

This extension provides a single unified set of query commands that can be used by applications to determine properties of various interfaces and resources used by program objects to communicate with application code, fixed-function OpenGL pipeline stages, and other programs. In unextended OpenGL 4.2, there is a separate set of query commands for each different type of interface or resource used by the program. These different sets of queries are structured nearly identically, but the queries for some interfaces have limited capability (e.g., there is no ability to enumerate fragment shader outputs).

With the single set of query commands provided by this extension, a consistent set of queries is available for all interfaces, and a new interface can be added without having to introduce a completely new set of query commands. These queries are intended to provide a superset of the capabilities provided by similar queries in OpenGL 4.2, and should allow for the deprecation of the existing queries.

This extension defines two terms: interfaces and active resources. Each interface of a program object provides a way for the program to communicate with application code, fixed-function OpenGL pipeline stages, and other programs. Examples of interfaces for a program object include inputs (receiving values from vertex attributes or outputs of other programs), outputs (sending values to other programs or per-fragment operations), uniforms (receiving values from API calls), uniform blocks (receiving values from bound buffer objects), subroutines and subroutine uniforms (receiving API calls to indicate functions to call during program execution), and atomic counter buffers (holding values to be manipulated by atomic counter shader functions). Each interface of a program has a set of active resources used by the program. For example, the resources of a program's input interface includes all active input variables used by the first stage of the program. The resources of a program's uniform block interface consists of the set of uniform blocks with at least one member used by any shader in the program.

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