[Bug 106053] Drawing at screen boundary is very slow.

https://bugs.freedesktop.org/show_bug.cgi?id=106053

--- Comment #5 from Roland Scheidegger sroland@vmware.com --- (In reply to Marek Olšák from comment #4)

I think the hw doesn't have a clipper, though it shouldn't be hard to verify if it's true. Yeah, draw could use some optimizations for the clipper, e.g. the guardband, but simply doing culling (not clipping) should be enough for point sprites.

That's what I meant with guardband clipping: there's no actual clipping, but the hw will still cull pixels outside the viewport. Hence it probably would be better if draw wouldn't clip if a primitive doesn't fit into the viewport, but fits into the (hw) guardband. (And you are right that point sprites are a bit of a special case.)