Kenneth Graunke
82a5ee6be4
Implementing the GetTransformFeedbackVertexCount() driver hook allows
the VBO module to call us with the right number of vertices.
The hardware doesn't directly count the number of vertices written by
SOL, so we instead use the SO_NUM_PRIMS_WRITTEN(n) counters and multiply
by the number of vertices per primitive.
Unfortunately, counting the number of primitives generated is tricky:
a program might pause a transform feedback operation, start a second one
with a different object, then switch back and resume. Both transform
feedback operations share the SO_NUM_PRIMS_WRITTEN counters.
To work around this, we save the counter values at Begin, Pause, Resume,
and End. This "bookends" each section where transform feedback is
active for the current object. Adding up differences of pairs gives
us the number of primitives generated. (This is similar to what we
do for occlusion queries on platforms without hardware contexts.)
v2: Fix missing parenthesis in assertion (caught by Eric Anholt).
v3: Reuse prim_count_bo rather than freeing it and immediately
allocating a new one (suggested by Topi Pohjolainen).
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
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 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. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. 1) install python 2.7 2) install scons (latest) 3) install mingw, flex, and bison 4) install libxml2 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get libxml2-python-2.9.1.win-amd64-py2.7.exe 5) install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe 6) install git 7) download mesa from git see http://www.mesa3d.org/repository.html 8) 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.