Ian Romanick
960d722bf7
Consider the following vertex shader and fragment shader:
// vertex shader
varying vec4 v;
uniform vec4 u;
void main() { gl_Position = vec4(0.0); v = u; }
// fragment shader
void main() { gl_FragColor = vec4(0.0); }
Since the fragment shader does not use 'v', it is demoted from a
varying to a simple global variable. Once that happens, the
assignment to 'v' is useless, and it should be removed. In addition,
'u' is no longer active, and it should also be removed.
Performing extra dead code elimination after demoting shader inputs
and outputs takes care of this. This elimination must occur before
assigning uniform locations, or the declaration of 'u' cannot be
removed.
This change *breaks* the piglit test getuniform-01, but that test is
already incorrect. The test uses a vertex shader that assigns to a
user-defined varying, but it has no fragment shader. Since Mesa does
not support ARB_separate_shader_objects (we only support the EXT
version), the linker correctly eliminates the user-defined varying.
The cascading effect is that the uniform queried by the C code of the
test is also (correctly) eliminated.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41980
Tested-by: Brian Paul <brianp@vmware.com>
Cc: Bryan Cain <bryancain3@gmail.com>
Cc: Vinson Lee <vlee@vmware.com>
Cc: José Fonseca <jfonseca@vmware.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Yuanhan Liu <yuanhan.liu@linux.intel.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.