random weirdness... bug? dodgy card?

[Graham]

recently I've been getting an odd artifact in my rendering,

The following image sums it up:

there are two textures being read, one for normals, one for linear depth. One is RGB565, depth is R16FP.

Whats odd is that I was getting random flickering where the depth sampling would be offset by 1 pixel on both the x or y axis. The fix was pretty easy (offset the sample by half pixel to fix the d3d corner sampling thingy). However I thought it was still odd the sampling would be different for both textures, given they are using the exact same vertex shader defined input.

anywho. I thought it was quite strange, so I'd post it just for the hell of it.

Although it's not as bad as the other bug I've been getting, where occasionally the screen flashes from full pink to bright green on alternate frames. However this is only happening when the d3d debug runtime is in use


However when I still think about it, I can't understand why the lines were appearing as is..


[edit]
ohh yeah both texture units were set to full point sampling too

 

[armchair_architect]

The debug runtime fills discardable backbuffers with green and pink after a Present. If you're seeing this on screen it usually means you're not clearing the backbuffer at the beginning of the frame, or not redrawing the entire scene (filling every pixel). Or you could have an extra Present being called, i.e. if your sequence is render, present, present, render, ... the second present in every frame will be filled with the debug color.

 

[Graham]

Ahh right. Thanks
XNA's timing isn't so wonderful, so I'm currently telling it to drop frames every so often.