Hello everybody, Yesterday I implemented Hardware Shadow Mapping (taking advantage of the nVidia's UltraShadow technology) on my 3D engine. Luckily it was easier than I expected :) I tested on my GeForce 6800 and it ran ok. But today I decided to try it on an ATI 2400+, hoping that the engine would automatically switch to standard Shadow Mapping (I use CheckDeviceFormat), and for my surprise, the engine started with Hardware Shadow Mapping enabled! So I went into debug mode, and I found that the ATI device allowed the use of a DEPTHSTENCIL usage texture with D24S8 format. Plus, I found that the intrinsic tex2Dproj returned the depth comparison as nVidia does! Is this normal? I thought that UltraShadow technology was a patent of nVidia. Did somebody have the same experience? Thanks in advance!

Oh, thanks for the answer, my mistake then... That's good news! So I ended up implementing a feature that goes beyond nVidia, without knowing that!
Well, thanks again! You made my day :)