In D3D9 and below, the rasterization rules are different from OpenGL. Offset your UVs by half a pixel. (ie: instead of 40.0f/texsize use 40.5f/texsize).

Quote:Original post by BradDaBug
Hey, that actually seems to work. Though now the text looks a little funny, like edges of the neighbor characters on the font texture are being printed along with the correct character.


What exactly is different between D3D and OpenGL in this case? The docs say that D3D considers 0 to be the pixel at one edge of the texture and 1.0 to be the pixel at the opposite edge, which (iirc) is the same way OpenGL works, so why is the half-pixel offset needed?

I can't speak for OpenGL, but with D3D, 0.0f is the left edge of the leftmost texel, 1.0f is the rightmost edge of the rightmost texel.

If you have a 2x2 texture, it'll be like so:

The point marked X has texture coords (0.25, 0.25), so if you want to use that texel you need to use (0.25, 0.25) as your UV coords. If you use 0.0, then you'd get the edge of the next texel (If the texture is wrapping).

Something else to check (Although I'm pretty sure it'll be correct) is that you're using AdjustWindowRectEx to get the correct client area size from the window size, since CreateWindowEx takes the size of the window, not the client area, and not adjusting for that will cause the backbuffer to be shrunk to fit the client area.

Also, you could try the reference rasterizer, in case it's a weird driver bug.

EDIT: Also, off topic - it's a good idea to post images as PNG rather than JPEG when you're talking about pixel issues like this, JPEG is lossy and causes some oddness around colour edges.

This explains it.