ummm, i'm not sure but I think you may have answered your own question about the z-buffer. You said your polygons are coplanar? Well then of course the z-buffer is going to have difficulty determining which surface should be drawn first/second and you will get a flickering effect between them alternating first/second drawn. Add a small offset into one of the polygons so it is definitely closer than the other one and the flickering will go away.

Hi

I'm having serious troubles with my d3d app (DirectX 6.1 interfaces), especially with Voodoo2 cards

First, the IDirect3DViewport3::Clear2 doesn't work when used with D3DCLEAR_TARGET (and I'm not too sure about the ZBuffer, since I get very strange ZBuffer artifacts, but not in *every* frame)

my app is quite simple at the moment
it draws a picture in the background using D3DTLVERTEX's as seen in many sdk samples
then I draw some triangles (with star texture) on top of it. Now on some areas they seem to be overlapped by the background, on some they are in front of the background, though they are coplanar

Hope someone can help me,
and Merry Christmas !

Martin "Bronto"

no, sorry, you got me wrong
the triangles in the front and the background are not coplanar
only the triangles in the front are coplanar

Martin