Marek Posts Mesa Tessellation Support For RadeonSI Gallium3D

It looks like OpenGL tessellation shader support within Mesa/Gallium3D is finally about to become a reality! Prolific Mesa contributor Marek Olšák has finished up the enablement work started by others and now has OpenGL tessellation working with the AMD RadeonSI Gallium3D open-source graphics driver.

Tessellation support is one of the few remaining items left for the OpenGL 4.0 compliance in Mesa and now at least RadeonSI can scratch it off the list while the other Mesa/Gallium3D drivers will likely finish up their support soon.

Marek is currently seeking developer review of the 5,000+ lines of code that make tessellation shaders happen for this open-source GPU driver handling Radeon HD 7000 series hardware and newer. Besides the RadeonSI code there's the relevant state tracker and Mesa+GLSL changes that will benefit the other drivers.

Working on this tessellation shader support over the past many months have also been Fabian Bieler, Chris Forbes, and Ilia Mirkin. The tessellation support is working with Unigine Heaven 4.0, TessMark, GpuTest, tessellation tutorials, and the Piglit test cases. Beyond needing the new code, LLVM 3.6.2 is also required for tessellation shaders to work on RadeonSI.

Marek announced this big achievement today on the Mesa mailing list while the code is presently in this branched Mesa Git repository. After this, all that's left for OpenGL 4.0 compliance is GL_ARB_shader_subroutine support that's already been started by David Airlie.