2b1cdb0edd
We can't use sampler messages with gradient information (like sample_g or sample_d) to deal with this scenario because according to the PRM: "The r coordinate and its gradients are required only for surface types that use the third coordinate. Usage of this message type on cube surfaces assumes that the u, v, and gradients have already been transformed onto the appropriate face, but still in [-1,+1] range. The r coordinate contains the faceid, and the r gradients are ignored by hardware." Instead, we should lower this to compute the LOD manually based on the gradients and use a different sample message that takes the computed LOD instead of the gradients. This is already being done in brw_lower_texture_gradients.cpp, but it is restricted to shadow samplers only, although there is a comment stating that we should probably do this also for samplerCube and samplerCubeArray. Because of this, both dEQP and Piglit test cases for textureGrad with cube maps currently fail. This patch does two things: 1) Activates the texturegrad lowering pass for all cube samplers. 2) Corrects the computation of the LOD value for cube samplers. I had to do 2) because for cube maps the calculations implemented in the lowering pass always compute a value of rho that is twice the value we want (so we get a LOD value one unit larger than we want). This only happens for cube map samplers (all kinds). I am not sure about why we need to do this, but I suspect that it is related to the fact that cube map coordinates, when transported to a specific face in the cube, are in the range [-1, 1] instead of [0, 1] so we probably need to divide the derivatives by 2 when we compute the LOD. Doing that would produce the same result as dividing the final rho computation by 2 (or removing a unit from the computed LOD, which is what we are doing here). Fixes the following piglit tests: bin/tex-miplevel-selection textureGrad Cube -auto -fbo bin/tex-miplevel-selection textureGrad CubeArray -auto -fbo bin/tex-miplevel-selection textureGrad CubeShadow -auto -fbo Fixes 10 dEQP tests in the following category: dEQP-GLES3.functional.shaders.texture_functions.texturegrad.*cube* Reviewed-by: Ben Widawsky <ben@bwidawsk.net> |
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docs/README.WIN32
File: docs/README.WIN32 Last updated: 21 June 2013 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. - install python 2.7 - install scons (latest) - install mingw, flex, and bison - install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe - install git - download mesa from git see http://www.mesa3d.org/repository.html - run scons General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.