#150042 - SiW - Tue Jan 29, 2008 8:35 am
I've just started DS development and I'm trying to get my head around the various VRAM banks.
Am I correct in thinking that I can't have two 16bpp background layers displayed on each screen at once? I'm having trouble figuring out how that's possible on the sub screen - no problem on the main screen.
#150047 - JanoSicek - Tue Jan 29, 2008 10:03 am
A 16-bit background is 96kB large.
Sub graphic can have at most 128kB VRAM allocated.
Therefore you cannot have two independent 16-bit backgrounds (aka framebuffers) on the sub.
If you want to do that, you must combine your two buffers in RAM and then copy the result to VRAM (slow slow slow)
Or you can use tiles instead of second layer (4096 colors in there)
#150049 - eKid - Tue Jan 29, 2008 10:19 am
A 128x128 16-bit background takes up 1/4 of sub-display vram, you can fit more than one of those. :)
#150057 - tepples - Tue Jan 29, 2008 12:50 pm
What do you get when you cover the sub screen with twelve 64x64 pixel sprites from bank D?
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#150060 - nipil - Tue Jan 29, 2008 1:23 pm
Why not use two 8-bit backgronds ? Coding difference is not that high, and the color degradation is usually small enough not to be noticable
#150063 - JanoSicek - Tue Jan 29, 2008 2:39 pm
| tepples wrote: |
| What do you get when you cover the sub screen with twelve 64x64 pixel sprites from bank D? |
Touche!
That's a nice workaround :)
#150071 - SiW - Tue Jan 29, 2008 3:41 pm
Thanks for the replies everyone, I definitely need to adjust my thinking - I've been lazily programming Windows apps for far too long!