Am Sa, den 01.01.2005 schrieb Roland Scheidegger um 19:00: > Felix Kühling wrote: [snip] > I'm a bit sceptical that this really improves depth buffer quality in > general. With D3D it is (if the hw supports it) possible to use a w > buffer instead of a z buffer, which has the same precision for far and > near objects. However, the loss of precision for near objects was often > considered unacceptable. (Radeon R100 and R200 support this, but R300 > and up no longer do, or at least the driver doesn't expose it, so it > looks like it wasn't that useful after all, and not many applications > afaik requested w buffers).
[... following up to my other reply ...] Another problem with W buffers is that linear depth interpolation doesn't give the correct results with intersecting surfaces. This is only achieved by the perspective division which is not applied to W (in fact the perspective division divides x, y and z by W). This makes W-buffers unsuitable for OpenGL. But this is not what I am proposing, just in case I was misunderstood. Reversing the depth range and using floating point numbers just changes the encoding of depth values in the depth buffer, it does not change the semantics, like a W-buffer would do. > > Roland -- | Felix Kühling <[EMAIL PROTECTED]> http://fxk.de.vu | | PGP Fingerprint: 6A3C 9566 5B30 DDED 73C3 B152 151C 5CC1 D888 E595 | ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
