I already tried making the particle texture 50% smaller. It didn't improve the quality.
Depends on how did you resize the texture to 50 %. If you used some filtering during the scaling (in Photoshop or whatever), it should look similarly to the first result.[/quote]I just tried it again, using Photoshop filtering. I rendered to the small RT using a smaller texture. The result is still very pixelated. "Small RT, small texture" looks only a little bit better than "Small RT, original texture".
If you render directly to a smaller texture, the result depends on your anti-aliasing settings[/quote]I think antialiasing never comes into play here. The circles you see are just textures, mapped onto square billboards. Antialiasing only smoothes the edges of triangles, and not the texture on them. Since the edges of our billboards are invisible, antialiasing has no effect in this case.
If you render to a texture and then scale down the texture, the resulting image will have gone through the texture’s bilinear filter.[/quote]Yes, that's what I'm doing. When I downsize the large RT, I use bilinear filtering. When I render the particles, I use bilinear filtering too.
Who can solve that mystery? ;)
When I downsize the large RT, I use bilinear filtering. When I render the particles, I use bilinear filtering too.
Maybe there's some tiny error somewhere making it that you think you're using it but in fact you aren't.
Another idea I had is that the lower mip level of your source tex might be bad (which is used for the low-res draw call).[/quote]Ah, good idea. I enabled mipmapping and now it looks very good
Of course, this doesn't tell my why it looked bad in the first place. When rendering to the fullscreen RT, I can render billboards of all different sizes, without any billboarding.
So there must be some other reason why it looked bad. Maybe the half-pixel offset?
However, the mipmapping looks good and is an acceptable workaround
Thanks everyone for your help!
