Perspective correction is different than texture filtering. Without perspective correction, textures look like what you get on a PSX... Nowadays, perspective correction is achived automatically by all 3d hardware. But here's i'm trying to do a software renderer. A software renderer is fun to implement but you have to face a lot of problems that have been eradicated for ages by various api or hardware.
I'm pretty sure now, that i've implemented it correctly except for triangles that are clipped at w=0.