> Increasing MAX_WIDTH/MAX_HEIGHT in Mesa does have it's problems if > you go too far though. > > Here's a little more detail from Brian Paul. > > Alan.
I increased MAX_WIDTH to 4096, and now Mesa works as it should. I have run "gears" all over the screen, and the Mesa demos as well, at almost 4000 x 2000 pixels. Thank you very much. I am now a happy man, and can finally go to sleep. A strange thing though: When running Mesa gears, it runs over all 6 screens in xinerama, but when running original gears, it only runs in the first screen, but the speed is the same. Does this mean Mesa is as fast as GLX, or what? Kim0 (More below) > ----- Forwarded message from Brian Paul <[EMAIL PROTECTED]> ----- > > Unfortunately, it's not that simple. Increasing MAX_WIDTH has a few > implications: > > 1. A number of temporary scan-line buffers are dimensioned to MAX_WIDTH. > On Macs there's a 32KB stack frame limitation. We're using some > macros (DEFMARRAY, etc) to allocate these temporaries in a number of > places. It works, but if we crank up MAX_WIDTH to 8K or 16K there'll > probably be some breakage. There's also evidence that large stack > frame allocations on Win32 cause slow-downs. That's not a real big > deal though... 4096 pixels is what I need, and it is below that breakage, and everything did indeed work well. > 2. The real issue may be with line/triangle rasterization. I'm using > fixed point math quite heavily in the triangle code. I'm afraid > that large values for MAX_WIDTH will cause overflow problems, causing > triangle drawing to blow up. I have not noticed that happen, so I guess 4096 is O.K. > I can't increase the default MAX_WIDTH too much (maybe 3K) until I've > done some testing to see what happens. Well, I ran the tests from Mesa, and I did not see any trouble. In fact, the program which takes the whole screen, started to work O.K. Anyway, I can test more stuff like that, since I have the machine for it. The main limitation is that it is just a 200MHz PII, so it is quit slow at the moment. > Feel free to forward this info to the xpert list if you want. > > -Brian Thank you for you help and advice. Kim0 _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
