On Mon, Dec 5, 2016 at 12:04 PM, Józef Kucia jkucia@codeweavers.com wrote:
This seems to be required for reading stencil values. The GL spec says "When sampling the stencil index only NEAREST filtering is supported.". The GL spec is inconsistent about this, but Mesa refuses to sample stencil index values with the GL_NEAREST_MIPMAP_NEAREST filter.
The NEAREST_MIPMAP_NEAREST is going to be allowed in Mesa (there is a patch for this [1]). However, the ARB_stencil_texturing spec was never updated, and an implementation of OpenGL which does not expose GL 4.5 doesn't have to allow using NEAREST_MIPMAP_NEAREST for stencil texturing.
[1] - https://lists.freedesktop.org/archives/mesa-dev/2016-December/137309.html