Roland Scheidegger
cf3fb42fb5
We were never producing negative numbers for signed types. Also fix only producing half the valid range for uint32, and properly clamp signed values. Because this now also properly tests snorm with actually negative values, need to increase eps for such conversions. I believe these cannot actually be hit in ordinary operation (e.g. if a snorm texture is sampled and output to snorm RT, it will still go through snorm->float and float->snorm conversion), so don't bother to do anything to fix the bad accuracy (might be quite complex). Basically, the issue is for something like snorm16->snorm8 that in the end this will just use a 8 bit arithmetic right shift. But the math behind it says we should actually do a division by 32767 / 127, which is ~258, not 256. So the result can be one bit off (values have too large magnitude), and furthermore, the shift has incorrect rounding (always rounds down). For positive numbers, these errors have different direction, but for negative ones they have the same, hence for some values the error will be 2 bit in the end. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=106232
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 https://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.