QUOTE(blue_knight @ Jan 26 2012, 11:59 PM)

So I was trying out the Quad rendering modes in 2.50 RC 2 since I was using them already for the "Mode 7" mode in World Tree (to be replaced by scanlines + pre-rotated DrawBitmap() for better quality when RC3 comes out)... Anyway when I switched over to RC 2.5 (I forget the exact version since the downloads are down, but DrawBitmap() works) - and Quad() no longer works properly at all - even with standard PT_TEXTURE rendering mode:
ZC 2.50 RC 2:

ZC 2.50 RC 2.5:

It only draws the first scanline of every quad for some reason.
I should probably add the DrawTile(), DrawCombo(), DrawBitmap(), Rectangle() and other drawing commands seem to work as intended, it's just Quad() that is broken (and maybe Triangle(), I haven't tried it).
Looks like (yet) another allegro bug. grrr...
...OK, Quad() and Triangle() are fixed now. Thanks for the report blue_knight.
Side Note* I can only reasonably optimize the most common cases because of how allegro handles sub-bitmaps here. That would be square PO2 sizes of 1, 2, 4, and 8. If you are using *lots* of oddly shapen texture rectangles each frame you might want to try and cache them somehow.