I am working to fix this issue.

kekko: yes, that code uses ALL fragment shaders. imo, the best way to go, since some Glide combiner/blend modes don't really have OpenGL analogues.

Any list of games with notable issues?

Ah, so that explains the depth tests then. I take it with the texture manager/cache, you are also taking care of textures not in use (eg. garbage collection)? I would imagine if textures are constantly allocated, there would be mem leaks....

I have to wonder why: if (FBZMODE_Y_ORIGIN(v->reg[fbzMode].u)) glOrtho( 0, v->fbi.width, 0, v->fbi.height, 0.0f, -1.0f ); else glOrtho( 0, v->fbi.width, v->fbi.height, 0, 0.0f, -1.0f ); Wouldn't it make sense if you use something like: glOrtho(0, outwidth, 0, outheight, -1.0, 1.0); instead rather …

need a hand from opengl experts with perspective correction/depth testing How are you doing your projection handling? If you are using glOrtho, I don't see your issue at all, since there is nothing to correct 😒 Are you sure all your coordinates for the textured quads are right?