Very nice, John. One terminology mistake though. Z-buffering and double
buffering are two different things. Z-buffering is a technique used for 3D
rendering, while double buffering is what the GBA uses. You simply switch which
buffer is the front buffer (the one that gets drawn on the screen) and which is
the back buffer (the one you want to draw to), just like you say.

As for your question, yes, it is possible to scale/rotate the background in
bitmap modes. Which makes for a nice method of rendering in mode 5 (courtesy of
Jonas Lund AFAIK). If you rotate the screen 90 degrees and scale it up, the
results won't look bad at all. Remember that the mode 5 resolution is 160x128,
while the screen is 240x160. So your graphics will be stretched to twice the
size on one axis, while staying the same on the other. Take this into account
(as well as the flipped x and y axis) and you're all set for full-screen, double
buffered 15 bpp rendering :)

----- Original Message -----
From: John Q. Pretentious
To: gbadev@yahoogroups.com
Sent: Sunday, March 31, 2002 2:54 AM
Subject: [gbadev] Long discussion of screen basics (was re: Sprite in mode 4)