GL4ES is a OpenGL 2.1/1.5 to GL ES 2.0/1.1 translation library, with support for Pandora, ODroid, OrangePI, CHIP, Raspberry PI, Android, Emscripten and AmigaOS4.

Opengl 2.1 with few tutorial of 3.3 later in the series in C following tutorials from lazyfoo but with SDL2, added improvement and few more features if possible

SpectrumColor Pro: Effortlessly pick, modify, and copy colors on Windows. Screen capture, hue control, presets, and versatile format support in a sleek interface.

An OpenGL 2.X demo. Some GLUT spheres rolling along the Z plane with misc effects.

A OpenGL 2.1/3.0 benchmark designed specifically to benchmark old and new PCs.