Intel's OpenSWR Rasterizer Starts Seeing Tessellation Support
Written by Michael Larabel in Intel on 24 January 2020 at 07:32 AM EST. 3 Comments
As more last minute work for the upcoming Mesa 20.0 is initial OpenGL tessellation support for Intel's OpenSWR driver.

OpenSWR is Intel's software rasterizer driver developed within Mesa as an alternative to Gallium3D's LLVMpipe and the slow Softpipe. OpenSWR is designed for delivering good CPU-based OpenGL graphics performance designed for visualization software running on workstations to HPC clusters. Like LLVMpipe, OpenSWR employs LLVM for some of its CPU optimizations.

Recently there's been work on OpenGL tessellation support for the software rasterizers and now in time for Mesa 20.0's feature freeze next week is some basic working support in the OpenSWR driver.

As of today in Mesa Git is TCS/TES shader compilation. Compiling tessellation shaders is now working but there are some acknowledged corner cases -- in particular some issues around transform feedback. This support is enough that TessMark and other test cases are running but not yet tessellation-heavy Unigine Heaven.

More details on this basic tessellation support via this merge request that was honored this morning.

Besides completing ARB_tessellation_shader, OpenSWR still needs to finish ARB_gpu_shader5 and ARM_sample_shading support before it will be at OpenGL 4.0 compliance.
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