OpenGL

Raspi VC4 hardware supports

• OpenGLES (https://www.khronos.org/opengles/) 1.1 and 2.0 and
• only a subset of OpenGL 2.1 (https://www.khronos.org/registry/OpenGL/specs/gl/glspec21.pdf)

OpenGLES is a subset of OpenGL for embbeded systems (ES), but many applications, especially games, rely on a fully supported OpenGL API. There are efforts to support all of OpenGL, see https://github.com/anholt/mesa/wiki/VC4-OpenGL-support with additional drivers (work in progress).

under Yocto

The images are configured to use the following software stack:

• OpenGLES client application like a Qt5 application or a SDL2 game.
• OpenGLES for 3D accelerated rendering (see /usr/include/GLES2/ header files)
• EGL as interface layer between the rendering API and the native platform windowing API (see /usr/include/EGL/ headers)
• framebuffer as native platform API for graphical output

Examples / Testing

OpenGL ES Book Samples

Examples from Munshi, Ginsburg, Shriner "OpenGL ES 2.0 Programming Guide". Forked from benosteen/opengles-book-samples:

root@raspberrypi3:~# git clone https://github.com/FrankBau/opengles-book-samples/
root@raspberrypi3:~# cd opengles-book-samples/Raspi
root@raspberrypi3:~/opengles-book-samples/Raspi# make
root@raspberrypi3:~/opengles-book-samples/Raspi# Chapter_2/Hello_Triangle/CH02_HelloTriangle 
 123 frames rendered in 2.0033 seconds -> FPS=61.3986
 ...

The famous red triangle is displayed on HDMI monitor. Rendering is synchronized to 60Hz display refresh rate.

Further reading

• https://open.gl/drawing
• https://www.raspberrypi.org/forums/viewtopic.php?f=67&t=179595&p=1142943&hilit=anholt#p1142818
• https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=178037&p=1134693
• https://www.raspberrypi.org/blog/libraries-codecs-oss/
• https://github.com/anholt/glmark2