Manfred Ernst
bf2c074a2f
Problem: The IEEE float optimized version of UNCLAMPED_FLOAT_TO_UBYTE in macros.h computed incorrect results for inputs in the range 0x3f7f0000 (=0.99609375) to 0x3f7f7f80 (=0.99803924560546875) inclusive. 0x3f7f7f80 is the IEEE float value that results in 254.5 when multiplied by 255. With rounding mode "round to closest even integer", this is the largest float in the range 0.0-1.0 that is converted to 254 by the generic implementation of UNCLAMPED_FLOAT_TO_UBYTE. The IEEE float optimized version incorrectly defined the cut-off for mapping to 255 as 0x3f7f0000 (=255.0/256.0). The same bug was present in the function float_to_ubyte in u_math.h. Fix: The proposed fix replaces the incorrect cut-off value by 0x3f800000, which is the IEEE float representation of 1.0f. 0x3f7f7f81 (or any value in between) would also work, but 1.0f is probably cleaner. The patch does not regress piglit on llvmpipe and on i965 on sandy bridge. Tested-by Stéphane Marchesin <marcheu@chromium.org> Reviewed-by Stéphane Marchesin <marcheu@chromium.org> Reviewed-by: Brian Paul <brianp@vmware.com>
File: docs/README.WIN32 Last updated: 23 April 2011 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons osmesa mesagdi to build classic mesa Windows GDI drivers; or 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. 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.