Topi Pohjolainen
933be19cdf
This is really not needed as blorp blit programs already sample
XRGB normally and get alpha channel set to 1.0 automatically by
the sampler engine. This is simply copied directly to the payload
of the render target write message and hence there is no need for
any additional blending support from the pixel processing pipeline.
The blending formula is anyway broken for color components, it
multiplies the color component with itself (blend factor is the
component itself).
Alpha blending in turn would not fix the alpha to one independent
of the source but simply used the source alpha as is instead
(1.0 * src_alpha + 0.0 * dst_alpha).
Quoting Eric:
"If we want to actually make the no-alpha-bits-present thing work,
we need to override the bits in the surface state or in the
generated code. In the normal draw path, it's done for sampling
by the swizzling code in brw_wm_surface_state.c, and the blending
overrides is just to fix up the alpha blending stage which
doesn't pay attention to that for the destination surface."
If one modifies piglit test gl-3.2-layered-rendering-blit to use
color component values other than zero or one, this change will
kick in on IVB. No regressions on IVB.
This is effectively revert of c0554141a9:
i965/blorp: Support overriding destination alpha to 1.0.
Currently, Blorp requires the source and destination formats to be
equal. However, we'd really like to be able to blit between XRGB and
ARGB formats; our BLT engine paths have supported this for a long time.
For ARGB -> XRGB, nothing needs to occur: the missing alpha is already
interpreted as 1.0. For XRGB -> ARGB, we need to smash the alpha
channel to 1.0 when writing the destination colors. This is fairly
straightforward with blending.
For now, this code is never used, as the source and destination formats
still must be equal. The next patch will relax that restriction.
NOTE: This is a candidate for the 9.1 branch.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Topi Pohjolainen <topi.pohjolainen@intel.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 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.