blu/hello-chromeos-gles2

"Hello GLES2" on ChromeOS, self-hosted style

Description

This is an experiment in self-hosted ChromeOS development focused on OpenGL ES. It relies on the ChromeOS-native GLESv2/EGL/Wayland stacks and as such should run on any ChromeOS device meeting the prerequisites, irrespective of Crouton conditions.

Warning: as of R69 RK3399-based chromebooks suffer from a system-wide (incl. not unmountig the filesystem) crash upon exiting the app -- see ticket #4.

Prerequisites

• A ChromeOS device in developer mode.
• ChromeOS revision with support for DRM render nodes, and a functioning Wayland server -- both found on ChromeOS revisions with support for Android apps, e.g. R67.
• Chromebrew

The following Chromebrew packages are required:

• buildessential (a meta package that may or may not include some or all of the follwing packages at the time of reading)
• gcc10
• wayland
• wayland_protocols
• linuxheaders

How to Build

Before you can build any of the applications you have to run build_wayland_protocols.sh in the source directory in order to generate the code for the required auxiliary wayland protocols. It is recommended to repeat that step after every update of Chromebrew package wayland_protocols.

Running one of the build_chromeos_xxx.sh scripts in the source directiory builds the respective test_egl_xxx executable. Currently the compiler is hard-coded to gcc/g++.

Tips

All test apps follow a common CLI scheme of universal args and app-specific args:

usage: ./test_egl_sphere [<option> ...]
options:
        -frames <unsigned_integer>              : set number of frames to run; default is max unsigned int
        -screen <width> <height> <Hz>           : set framebuffer of specified geometry and refresh
        -bitness <r> <g> <b> <a>                : set framebuffer RGBA bitness; default is screen's bitness
        -fsaa <positive_integer>                : set fullscreen antialiasing; default is none
        -drawcalls <positive_integer>           : set number of drawcalls per frame; may be ignored by apps
        -device <unsigned_integer>              : device index in /dev/dri/cardN sequence
        -app <option> [<arguments>]             : app-specific option

Example of CLI usage:

$ LD_LIBRARY_PATH=/usr/lib:/usr/local/lib XDG_RUNTIME_DIR=/run/chrome EGL_LOG_LEVEL=warning ./test_egl_xxx -frames 2000 -bitness 8 8 8 8 -screen 640 640 60

The above:

• Makes sure factory-supplied libraries are preferred over chromebrew-supplied ones (via 'LD_LIBRARY_PATH' envvar).
• Tells libwayland-client where to find wayland sockets (via 'XDG_RUNTIME_DIR' envvar).
• Sets the libEGL diagnostics to 'warnings-only' (via 'EGL_LOG_LEVEL' envvar).
• Specifies 2000 frames worth of runtime.
• Specifies framebuffer pixel format of RGBA8888 (others supported are RGBA8880 and RGBA5650).
• Specifies framebuffer geometry of 640x640x60Hz (refresh is required yet conveniently ignored).

Notes:

• You may need superuser privileges to use the export-buffer DRI functionality, used for on-screen presentation of our framebuffer.
• On platforms with multiple /dev/dri/cardN devices, some of those may deny creation of 'dumb' DRM buffers, which makes such devices useless to us.
• Resizing at runtime, including switching to fullscreen, is not supported.

References

• Jan Newmarch Programming Wayland Clients
• Henrique Dante de Almeida The Hello Wayland Tutorial