@moxee

Hank you for reply

@Spirantho

The OpenGL only helps. In screen resize(like overlay in video playback) the emulation Speed was affected for example by using 8 bit instead of 16 bit to draw the video...


edit:miiswrite from cellphone...

Last edited by Tuxedo on 07-Mar-2013 at 07:36 AM.
Last edited by Tuxedo on 07-Mar-2013 at 07:36 AM.

_________________
Simone"Tuxedo"Monsignori, Perugia, ITALY.

@Spirantho

Quote:

Spirantho wrote: @Jupp3 OpenGL is used by SDLMAME for its display scaling. On my 600MHz Sam, with software renderer, space invaders runs at 33% with a larger screen size. With my first OpenGL build, it runs at over 100%. That's an unusual case, but believe me it can help a lot.

What I meant to say, MAME itself doesn't benefit from OpenGL at all. It just "draws pixels to a surface" and that's about it. It's up to the MAME port on whatever platform you are running, what / how to do with those pixels.

If some MAME port lacks overlay, then it might well be "less heavy" to draw it with OpenGL.

I haven't looked at the code, but I'd guess it's something like:
1)MAME draws screen to an array in RAM.
2)MAME port uploads the pixel data from the array to a texture in graphics ram (this might include pixel format conversion)
3)MAME port draws a fullscreen quad with the texture, that was just uploaded.

Repeat for next frame.

I just can't help the feeling about OpenGL being "the wrong tool" for this. If someone ever started writing a 3D accelerated replacements for various 3D hardware emulation that MAME has (which, of course, makes it "inexact", which is againist what MAME is done for), then it should be an obvious choice. Of course this would be far from an easy task, and probably wouldn't get rid of all 3D hardware emulation (remember that MAME runs compiled code, it's just not possible to modify all games to use OpenGL directly) but something, that will replace code for drawing triangles with an OpenGL equivalent wouldn't be 100% unrealistic.