Quads

[Frank]

When the rasterizer generates quads to go into the pixel pipelines, do they have to be a sqare piece of screen? Ie. if a pixel is not part of the triangle, is that place in the quad unused? Or does the rasterizer just issues 4 pixels? And how about triangles that are only one or a few pixels in size?

I was under the impression, that the NV3x uses square pieces, while the R3x0 issues 4 pixels. Is that correct?

And if only square pieces are used, do they always have to fill the same spot on the screen (ie. 0,0-1,1 or 0,2-1,3), or is that not important?

 

[Dave Baumann]

Under present hardware quads are 2x2. Pixels are always alloated from a triange, however if it is a small triangle, or at an edge then some of the processing will go to waste.

 

[Simon F]

And if only square pieces are used, do they always have to fill the same spot on the screen (ie. 0,0-1,1 or 0,2-1,3), or is that not important?

That'd be very much implementation dependent. There'd be pros and cons for both fixed and non-fixed alignment.