Slow performance using glDrawElements calls with GL_UNSIGNED_BYTE indices

Submitted by Logan McNaughton

Assigned to Default DRI bug account

Description

Original application bug report here:

https://github.com/gonetz/GLideN64/issues/1561

This bug happens using mupen64plus (N64 emulator) and the GLideN64 graphics plugin.

The application uses VBO streaming (https://www.khronos.org/opengl/wiki/Buffer_Object_Streaming) using ARB_buffer_storage to upload the VBO data.

Multiple users that when using Mesa + r600 driver, the performance was abysmal. It turns out that converting the glDrawElementsBaseVertex calls to glDrawArrays fixed the problem.

You can see the commit that fixed the problem here:

https://github.com/loganmc10/GLideN64/commit/9bcfa67d9550c7f1cd4ba72f657facd66a4d27e4

Version: 17.3

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