Contents - Raspberry PI Community Projects

documentation is contained within comments in the header files, as well as
documentation for the OpenMAX IL components in the documentation directory on
Github (https://github.com/raspberrypi/firmware/tree/master/documentation/
ilcomponents) , however it is severely lacking and difficult to understand in a general
sense for people wanting to experiment with the device due to it being proprietary. As
such, we encourage you to edit this page (http://elinux.org/
index.php?title=RPi_VideoCore_APIs&action=edit) to help us build a much better open
documentation.
Quirks
▪ The Raspberry Pi requires that the bcm_host_init() function is called first
before any GPU calls can be made.
▪ Before calling any of the vc_* functions, you need to initialise vcos and vchi, and
make a vchi connection, before then calling the corresponding vc_*_init function
for the part of the library you want to use: vc_vchi_dispmanx_init,
vc_vchi_tv_init, vc_vchi_cec_init or vc_vchi_gencmd_init.
(See this sample code (https://github.com/adammw/rpi-output-swapper/blob/
master/video_swap.c#L152-169) which does initialisation for vc_tvservice_*
APIs)
▪ Linking against the EGL library (-lEGL) also requires you to link against the
GLESv2 library (-lGLESv2).
▪ graphics_get_display_size() is a broadcom-specific function
Built-in Sample Programs
The Raspberry Pi comes with 7 sample programs and two helper libraries in the /opt/vc/
src/hello_pi directory showing some of the system's capabilities and sample code.
hello_video
This sample decodes h264 video using the OpenMAX APIs and the ilclient library, and is
distributed with a short scene of Big Buck Bunny (http://www.bigbuckbunny.org/)
hello_audio
This sample plays a sine wave for ten seconds using the ??? APIs.
hello_triangle
This sample shows how to get a OpenGL ES context on the Raspberry Pi.