Well, my disks just spun up for the nightly updatedb cron, so that's my cue to go to bed, but I wanted to give you a quick update. I've got scissors and cliprects working, with the exception of overlapping GL windows having some problems, but we had that problem before. I'm probably going to commit this tomorrow, but I wanted to experiment a bit more and possibly do some cleanup. I'm not sure that I have all the state updates in the right places, I want to make sure that everything is updated when it needs to be but not when it doesn't.
I've looked at several drivers for these changes, and they are all a bit different. Anyway, I figured out that the viewport calculation needed the x and y offsets to the origin of the window added in. I did this by storing the offsets in 2 context vars, which is what some other drivers do. r128 seems to have a cce register to handle the offsets. Cliprects seem to be working right now with some more changes. Basically, my (most likely somewhat flawed) understanding is this: Scissors -------- The scissors are register settings that determine a hardware clipping rect in window coords. Any part of a primitive or other drawing operation that extends beyond the scissors is not drawn. The scissors can be set through GL commands. This has nothing to do with perspective clipping in the pipeline, just the final window coordinates. Cliprects --------- Cliprects are used to determine what parts of the context/window should be redrawn to handle overlapping windows. The more overlapping windows, the more cliprects you have. These need to be passed to the drm. It does a clear or swap for each cliprect. Again these are for 2D clipping after rasterization and not part of the pipeline. Things get a bit complicated by the fact that there can be separate clip rects for the front and back buffers. Viewport -------- The viewport array holds values to determine how to translate transformed, clipped, and projected vertex coordinates into window coordinates. This is the last stage of the pipeline. The values are based on the size and position of the "drawable", aka the drawing area of the window for the context. I'm attaching the diff of my mesa driver directory so you can have a look before I commit it. There's also a couple of small changes in the drm for this (which I didn't include in the diff), to make it use the scissor and mask values from the sarea register context. -- Leif Delgass http://www.retinalburn.net
mach64-clipping.diff.gz
Description: mach64-clipping.diff.gz
