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man, you could be the same person who hacked my pc.

the answer is that it's definately the filter you've applied.
It happens when I use trilinear filtering on texture stage 2.

Don't start your UVs at 0,0. Start them at 0.5 texels (ie 0.5/256.0 for a 256x256 texture). When you say UV 0,0 you're saying it's half the first pixel and half the last pixel, resulting in guaranteed wrapping with anything but a point filter.

In OpenGL starting at 0,0 would be correct. In DirectX it's not.

edit: Oh, and since you're projecting... perhaps you should use CLAMP or BORDER texture addressing (and set border to transparent, or black or whatever won't show up for you).

You might be able to adjust your clipping planes to cut off at the 0.5 texel mark instead of the changing the addressing instead. Whichever is easiest.

Quote:

Original post by Namethatnobodyelsetook Don't start your UVs at 0,0. Start them at 0.5 texels (ie 0.5/256.0 for a 256x256 texture). When you say UV 0,0 you're saying it's half the first pixel and half the last pixel, resulting in guaranteed wrapping with anything but a point filter. In OpenGL starting at 0,0 would be correct. In DirectX it's not.

Thank you !! The problem disappeared when i added those 0.5 texels. (btw my addressing mode was CLAMP).

that's not what worked for me ...
I have got a function that set's a texel aligning projection matrix and I definately use a clamp address mode.

when I apply a trilinear filter to the projected texture channel I get the artifact as shown in the picture.

How could the trilinear filter mess with the texel alignment in order to produce such an effect?

I can post code and screenshots if you want/.

i suppose the trilinear filter interpolates the color value located at the texture's edges, so that they are no longer black and transparent, therefore this problem.