Bryan Cain
691cc0e3a8
Logical-or is implemented using addition (followed by clamping to [0,1]) on
values of 0.0 and 1.0. Replacing the logical-or operators with addition gives
a + b which has a result on the range [0, 2].
Previously a SNE instruction was used to clamp the resulting logic value to
[0,1]. In a fragment shader, using a saturate on the add has the same effect.
Adding the saturate to the add is free, so (at least) one instruction is
saved. In a vertex shader, using an SLT on the negation of the add result has
the same effect. Many older shader architectures do not support the SNE
instruction. It must be emulated using two SLT instructions and an ADD. On
these architectures, the single SLT saves two instructions.
Note that SNE is still used when integers are used for boolean values, since
there is no such thing as an integer saturate, and older shader architectures
without SNE don't support integers.
This is a port of commit 41f8ffe5e0 to glsl_to_tgsi with integer support
added.
WindML Driver for Mesa 4.0
Requirements
------------
Tornado 2 + WindML, Cumulative Patchs are recommended.
I suppose you have a valid WindML installation. Double buffer hardware
gives better performance than double buffer software so if you can
compile your WindML driver with this option, just do it. I/O
redirection is adviced in target server.
Tested on
---------
During the development, my main target was a CoolMonster:
- Video card: CT69000
- CPU: PENTIUM 266MHz
and my host a Windows NT + Tornado 2.
Installation
------------
1. Mesa sources must be in root directory (C:\)
2. Add the following line to your torVars.bat:
set MESA_BASE=C:\Mesa
OR copy the new torVars.bat in your bin path:
c:/Mesa/src/ugl/tornado/torVars.sample ->
/mnt/nt/Tornado/host/x86-win32/bin/torVars (for example)
3. In a command prompt:
$ torVars
$ cd c:\Mesa
$ make -f Makefile.ugl CPU=PENTIUM
Take a long while...
5. Include all the files from ugldemos folder to build some downloadable
application modules
4. Download UGL/Mesa object files on target
For example via the WindShell:
ld < c:\Tornado\target\lib\objMesaGL.o
ld < c:\Tornado\target\lib\objMesaUGL.o
ld < c:\Tornado\target\lib\objMesaGLU.o
ld < c:\Tornado\target\lib\objGLUTshapes.o
ld < c:\Tornado\target\lib\objMesaOS.o
You can put the previous lines in a file and use:
< filename
6. Download the application modules.
7. In WindShell, run:
-> uglalldemos
During the show some messages will appear, it provides some useful
information on key management.
Coding
------
Sample Usage:
In addition to the usual ugl calls to initialize UGL, (may be find an
input driver), you must do the following to use the UGL/Mesa interface:
1. Call uglMesaCreateContext() to create a UGL/Mesa rendering context,
given the display format.
2. Call uglMesaMakeCurrent() to bind the UGL/Mesa buffers to an
UGL/Mesa Context and to make the context the current one.
3. Make gl* calls to render your graphics.
4. Use uglMesaSwapBuffers() when double buffering to swap front/back buffers.
5. Before the UGL is destroyed, call MesaDestroyContext().
6. Before exiting, call if required uglEventQDestroy and then
uglDeinitialize();
Limitations
-----------
I found the following limitations in my driver :
- Color Indexed management is only in 8 bits
- It's possible to mix UGL/OpenGL application with a software
double buffer
Modifications
------------
New files in Mesa:
- Makefile.ugl
- rules.windmlmesa
- docs/README.UGL
- include/GL/uglmesa.h
- si-glu/Makefile.ugl
- src/Makefile.ugl
- src/ugl/torGLUTShapesInit.c
- src/ugl/torMesaUGLInit.c
- src/ugl/ugl_api.c
- src/ugl/ugl_dd.c
- src/ugl/ugl_glutshapes.c
- src/ugl/ugl_line.c
- src/ugl/ugl_span.c
- src/ugl/ugl_tri.c
- src/ugl/uglmesaP.h
- ugldemos/*
Modified files in Tornado 2.0:
- c:\Tornado\host\x86-win32\bin\torVars.bat
rem Command line build environments
set WIND_HOST_TYPE=x86-win32
set WIND_BASE=C:\Tornado
set MESA_BASE=C:\Mesa
set PATH=%WIND_BASE%\host\%WIND_HOST_TYPE%\bin;%PATH%
- c:\Tornado\target\config\comps\VxWorks\01uglmesa.cdf
- c:\Tornado\target\h\GL\*
Todo
----
- GCC 2.96, ASM compilation
Thanks to:
----------
Precision Insight team for their great job around Mesa, XFree, and DRI.
Wind River Systems to take me as an intern.
Stephane Raimbault
<stephane.raimbault@windriver.com>
<stephane.raimbault@deesse.univ-lemans.fr>
July 24, 2001