Wednesday, May 23, 2012

Title screen

Compressed title screen tiles have been loading for a while, but I'm currently working on how they are assembled into the actual title screen and Squaresoft logo.  Looks pretty simple, actually.

See?  See?  I'm doing things.

Edit: I'm also checking out the tree graphic behind the title screen, since it's been somewhat of a mystery for a while now.  Looks like they're doing some sort of peculiar matrix math on 8x8 blocks of data derived (somehow) from around D2E63B in the ROM, which end up becoming the tiles that go off to VRAM.

Funny how slow this loading is - they start doing it while the Squaresoft logo is up, and are still working on it while the little black window opens up and shows part of the background, which loads from the bottom up.  Once it finishes (~20 seconds later), it opens up and shows the rest.  They pass it off as a stylish little window into the background, but it's really just there to allow you to see the part of the image that's been loaded without revealing the part where the little blocks are still being filled in.  Corrupting the data in certain ways will slow the algorithm down enough that I can watch it populate the tiles while they're being shown.

Kind of interesting though, that they managed to set up sort of a "background task" like this in an SNES program, that will sit there and load tiles while the rest of the title screen is running.  I'm betting they tried like hell to make it load real-time before they finally gave up and had to go this route.

Oh, and this code is largely runtime-generated and run off of RAM addresses, which makes it even more fun to follow.

Needless to say, making this thing "editable" should be quite the task.

3 comments:

Matt said...

Great to see you are not dead yet (again) :D

Thanks for your work, I love your project!

rhx-retrohelix said...

This was an short but interesting read. Keep posting such things.

Nice to see you are on it again.

Alberto SalimHaubold said...

Good to see you are working on it. The thing about the "corrupted/smaller" image you get is because they actually made it smaller in the US American version. If you check the japanese version intro (can do it on youtube) you'll notice that the image is larger but has the japanese characters for "Seiken Densetsu 2" embeded into it. I guess they couldn't remove thr logo at the time and just chopped the image so it wouldn't show the japanese chars.