Keith Whitwell wrote: > Rune Petersen wrote: >> It turns out I missed something obvious... >> >> The parameters are passed correctly, I have just not transformed the >> vertex.position to the fragment.position > > I guess that's the viewport transformation, or maybe a perspective > divide followed by viewport transformation.
I did do a viewport transformation, but I didn't map the z component from a range of [-1 1] to [0 1]. Perspective divide is also needed, but not in my test app (w=1) ATI appears to do perspective divide in the fragment shader. I hit a problem constructing this: - In order to do range mapping in the vertex shader (if I so choose) I will need a constant (0.5), but how to add it? - If I do perspective divide in the fragment shader, I will need to remap the WPOS from an INPUT to a TEMP. > > But I think there's a bigger problem here -- somehow you're going to > have to arrange for that value to be interpolated over the triangle so > that each fragment ends up with the correct position. > > Maybe they are being interpolated already? I guess it then depends on > whether the interpolation is perspective correct so that once > transformed you really get the right pixel coordinates rather than just > a linear interpolation across the triangle. Is there a way to visually verify this? Rune Petersen ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV -- _______________________________________________ Dri-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dri-devel
