Igalia Is Working On "mediump" Support For Mesa To Help With OpenGL ES Performance

Igalia is working on supporting OpenGL ES' GLSL marking of variables as "mediump" when the precision involving those variables can be lowered to half-float 16-bit registers. That in turn can help with performance when honoring that precision marking, which to date Mesa has ignored.

It turns out Igalia has been working on that Mediump support for Mesa's OpenGL ES with a focus on the Freedreno Gallium3D driver. Interestingly, it's under contract for Google -- they sure are ramping up their work on this open-source Qualcomm Adreno driver. Besides employing developers like Freedreno founder Rob Clark and former Broadcom VC4/V3D developer Eric Anholt, they are also contracting Igalia as part of the Freedreno effort.

Neil Roberts of Igalia was talking about Mediump support on Wednesday as part of the XDC2019 conference happening now in Canada. In allowing for lower precision, on most hardware this can mean greater performance. But before anyone asks in the forums, this "mediump" marker though is only supported under OpenGL ES and not the desktop OpenGL specification. While Igalia's work is tailored to the Freedreno driver, much of their Mesa undertaking is relevant to any driver as it's being implemented as a pass on the NIR intermediate representation. As most Phoronix readers know, nearly all of the Mesa drivers support NIR in some fashion.

Those wishing to learn more about this "mediump" support can go through Neil's slide deck for XDC 2019 on the topic.