News:New OpenGL management in Funtoo

New OpenGL management in Funtoo

Funtoo is switching to an improved system for managing multiple OpenGL providers (Mesa/Xorg, AMD and nVidia). The update may involve blockers and file collisions.

By Mgorny / February 28, 2015

New OpenGL management

System principles

The new OpenGL management design assumes that the reference OpenGL implementation (mesa/Xorg) is to be used to build packages. After switching to the new system, all packages will use the mesa/Xorg headers and link to the mesa/Xorg libraries. This improves portability of software built on Funtoo and solves some of the build failures when non-standard OpenGL provider was enabled.

The third-party OpenGL libraries and modules provided by proprietary driver vendors can be enabled for run-time program use. They will not affect how the program is built. However, they will be loaded by the dynamic loader when starting executables. The Xorg server will also load the modules provided by blob driver vendor if appropriate.

Implementation

The reference implementation (mesa/Xorg) packages install headers and libraries into standard system locations (/usr/include, /usr/lib*). The compiler and linker finds them using the usual rules and uses them.

The third-party OpenGL vendors install libraries and server extension modules into vendor-named subdirectories of /usr/lib*/opengl. Those files are not used directly.

app-admin/eselect-opengl is used to select OpenGL implementation used at run-time. The choice of implementation is controlled via dynamic linker configuration (ld.so.conf) and Xorg server configuration. If the reference implementation is selected, the eselect module outputs null configuration that causes the linker and server to use the standard paths. If an another implementation is selected, the configuration prepends /usr/lib*/opengl paths to linker and server configuration, causing them to prefer the third-party libraries over reference.