Am Donnerstag, den 01.08.2019, 07:22 -0400 schrieb Ilia Mirkin: > Hey Gert, > > I'm looking at > https://cgit.freedesktop.org/mesa/mesa/commit/?id=b048d8bf8f056759d1845a799d4ba2ac84bce30f > , which attempts to implement depth clamping (rather than clipping) > with shader tricks. > > You're forcing the final vertex stage's position's depth to 0, and > then making up for it in the frag shader with an extra varying. > However won't this screw up the barycentric coordinates for > perspective interpolation? i.e. won't you effectively always just get > noperspective interp everywhere as a result? That is probably true, I was following @kumas lead [1], in fact he implemented the initial version of this code, and I only fixed it up for ARB_clip_control and GS and TES shaders.
One fix I could think is maybe clamp the z value to the clip range [-1, 1] or [0,1] depending on the clip control z accuracy, so that the error only happens only for the clamped areas where the result is distorted anyway, what do you think? Best, Gert [1] https://stackoverflow.com/questions/5960757/how-to-emulate-gl-depth-clamp-nv > > -ilia > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
