[uae] Re: e-uae runngin on DirectFB at last!

  • From: Richard Drummond <evilrich@xxxxxxxxxxxxxx>
  • To: uae@xxxxxxxxxxxxx
  • Date: Tue, 13 Mar 2007 21:10:21 -0400

Hi Manuel

On Monday 12 March 2007 15:53, Manuel Alfayate wrote:
> There's only a thing that makes my emulated e-uae-based enviroment slightly
> inferior to a real AMIGA: a perfect V-sync-ed video mode for apps/games
> that require smooth scrolling routines. 

There are a couple of problems here. Firstly, an SDL application doesn't know 
anything about refresh rates. You can't tell SDL "give me a 50Hz screen". 
Secondly, when using 2D, you don't know whether SDL is using vsync or not 
(with OpenGL via SDL you can know, at least since around SDL 1.2.10). The 
third problem is whether the underlying graphics system actually supports 
synchronizing with the vertical blank or not.

The first two problems can be solved by writing a DirectFB back-end for E-UAE. 
There'll be one soon. 

The third problem, I don't know yet. It's been a while since I played around 
with this stuff in the Linux framebuffer layer, but I seem to remember 
DirectFB polls for vertical-blank status - if it's supported at all (depends 
on the graphics chipset). There were some patches kicking around to add 
interrupt support for vertical-syncing, for example, for Matrox chipsets. I 
need to refresh myself on the state of the art, fbdev-wise.

What gfx chipset is in your Mac Mini, BTW?


In recent snapshots of E-UAE, the gfx_vsync=true option works on Mac OS when 
using OpenGL rendering (i.e., set sdl.use_gl=true). The SDL problem strikes 
again, though, and you can't choose the refresh rate when running 
full-screen. Unless you can miracously get a refresh rate that's equal to the 
refresh rate of the Amiga screen (50HZ for PAL) or an integer multiple of 
that (e.g., 100HZ), then screen update will not be smooth. It'll be 
flicker-free, but not smooth.

Cheers,
Rich
-- 
Richard Drummond

Web:  http://www.rcdrummond.net/
Mail: mailto:evilrich@xxxxxxxxxxxxxx

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