- Example OpenGL ES2 demo using GBM and DRM (KMS) modesetting
- This shows how ChromeOS renders GLES2 contents on the screen.
- It uses OpenGL ES2/3 without X11 dependency, so it fits pretty good with the embedded devices world.
- If you are on Ubuntu, first make sure you have the dependencies installed
> sudo apt-get install libgles2-mesa-dev libgbm-dev
> mkdir build; cd build
> cmake ../
> make
- I have successfully ran it on Ubuntu, ChromeOS and Yocto.
- Go to tty1 with Ctrl + Alt + F1
- Kill gdm or lightdm because they are DRM master now. This demo has to be DRM master.
> sudo service lightdm stop
- Run the demo
> gbm_es2_demo
or
> gbm_es2_demo -M # mmap test
- The easiest way to build embedded linux image is to use Yocto.
- I make Yocto recipes to make standalone emebeded OpenGL ES2 demo image.
- Check Yocto GBM ES2 Demo
- Enjoy building Linux image from the scratch.
- Show how to glue DRM, GBM and EGL
- Show how to swap buffer and vsync
- Show how to implement GLES2 app
- Same to gbm_es2_demo except for updating cube surface using dma_buf mmap
- It's very nice demo to show how Chromium zero-copy texture upload works. Chromium doesn't use glTexImage2D to update texture thank to new dma_buf mmap API. For more Chromium detail, check the chrome issue
- After Linux kernel v4.6, you can use following code. (currently only Intel Architecture supports it)
- Tiago Vignatti made this change in kernel.
void* data = mmap(dma_buf_fd)
update contents on |data|
munmap(data)
- The style complying with Chromium’s style guide
- Before submitting a patch, always run
clang-format
> clang-format-5.0 -i `find . -name "*.cpp" -o -name "*.h"`