Roland Scheidegger
dbb2cf388b
The motivation actually was to get rid of the additional tex instruction, since that requires the draw fallback code to intercept all sampler / view calls (even if the fallback is never hit). Basically, the idea is to use coverage of the pixel to calculate the alpha value, and coverage is simply based on the distance to the center of the line (in both line direction, which is useful for wide lines, as well as perpendicular to the line). This is much closer to what hw supporting this natively actually does. It also fixes an issue with line width not quite being correct, as well as endpoints getting stretched too far (in line direction) with wide lines, which is apparent with mesa demo line-sample. (For llvmpipe, it would probably make sense to do something like this directly when drawing lines, since rendering two tris is twice as expensive as a line, but it would need some changes with state management.) Since we're no longer relying on mipmapping to get the alpha value, we also don't need to draw 3 rects (6 tris), one is sufficient. There's still issues (as before): - quite sure it's not correct without half_pixel_center, but can't test this with GL. - aaline + line stipple is incorrect (evident with line-sample demo). Looking at the spec the stipple pattern should actually be based on distance (not just dx or dy for x/y major lines as without aa). - outputs (other than pos + the one used for line aa) should be reinterpolated since we actually increase line length by half a pixel (but there's no tests which would care). v2: simplify the math (should be equivalent), don't need immediate v3: use float versions of atan2,cos,sin, minor cleanups Reviewed-by: Brian Paul <brianp@vmware.com> Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
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.