On Saturday 12 March 2005 02:33, Lourens Veen wrote: > On Saturday 12 March 2005 03:50, Timothy Miller wrote: > > On Wed, 9 Mar 2005 09:47:42 +0100, Martijn Sipkema wrote: > > > From: "Timothy Miller" <[EMAIL PROTECTED]> > > > > For implementing FSAA, I can't remember whether it's called > > > > multisampling or supersampling, but the easy technique is to > > > > have a stage in the pipeline that divides the geometry down and > > > > manipulates the alpha channel so as to convert 2x2 pixels into > > > > one pixel in the framebuffer. This is trivial to implement, > > > > and I can add it in. > > > > > > That won't work I think as information on subpixels is lost on > > > converting to a single fragment with alpha---that conversion is > > > to be done after all drawing is completed, I think... > > > > All 3D drawing, yes. I was going to insert it just before the > > extra stuff I inserted to do 2D stuff that OpenGL doesn't account > > for. > > I've been thinking, would it be acceptable to lose the hardware > overlay scaler when FSAA is turned on, and/or to only have FSAA in > full-screen OpenGL mode?
Why do you think the two are incompatible? > The way the hardware overlay scaler works is that it takes the > framebuffer, and a second buffer with video data. It copies the > framebuffer to output, except for pixels with a certain colour key > where it switches to a colour-converted (YUV->RGB), scaled (with > linear interpolation?) version of the second buffer. So, that has to > happen right before the DAC. Is that all correct? > > In that case, you could add a small amount of extra logic to the > overlay scaler (basically, you have to be able to tell it to ignore > the framebuffer input altogether and just give a scaled version of > the second input, and you need to be able to turn off the YUV->RGB > conversion, which you need to do anyway) and you could trade off > quality against speed arbitrarily. For example, you could render the > scene at width*sqrt(2), height*sqrt(2) to get one half the fillrate > but still some AA. Why does video need a dedicated scaler instead of being handled as a texture? This just leaves the YUV->RGB conversion, which can be a property of the window, picked up by the window ownership test. But do we really need YUV->RGB on the card? Why not do this on the host? Regards, Daniel _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
