What exactly is PyOpenGL-accelerate?

Question

The title is the main question here. I had some PyOpenGL code I was running on my computer, which was running somewhat slow. I realized I hadn't installed PyOpenGL-accelerate. This didn't change the speed at all, but most tutorials with the Python OpenGL bindings suggest that PyOpenGL-accelerate should be installed.

What exactly does this module do?

Answer 1

First of all note that PyOpenGL-accelerate isn't a silver bullet. Thereby if you're already poorly optimizing your application, then PyOpenGL-accelerate wouldn't gain you that much if any additional performance.

That being said. PyOpenGL-accelerate consist of Cython accelerator modules which attempt to speed up various aspects of PyOpenGL 3.x. Thus if you're using glBegin() and glEnd() to draw with, then you won't gain any performance from this.

So what is Cython accelerator modules?

These modules are completely self-contained, and are created solely to run faster than the equivalent pure Python code runs in CPython. Ideally, accelerator modules will always have a pure Python equivalent to use as a fallback if the accelerated version isn’t available on a given system. The CPython standard library makes extensive use of accelerator modules.

– Python – Binary Extensions

In more layman's terms. Cython is a bit of a mix between Python and C so to speak. With a goal being optimization and execution speed.

In relation to PyOpenGL-accelerate this means that the various helper classes PyOpenGL offers. Is instead implemented in a manner that offers more performance.

Answer 2

From the documentation:

This set of C (Cython) extensions provides acceleration of common operations for slow points in PyOpenGL 3.x. For code which uses large arrays extensively speed-up is around 10% compared to unaccelerated code.

You could dig through the code if you want to know precisely which optimizations are defined, but OpenGL is usually built around surprisingly coarse optimizations to account for different hardware - i suppose that extends to running off of an interpreter as well.