evilhamwizard, on 30 May 2015 - 09:32 PM, said:
ICEknight, on 30 May 2015 - 09:07 PM, said:
LOst, on 30 May 2015 - 06:54 PM, said:
As for the parallax scrolling techniques often talked about in this demo:
I did found a few references in Sonic 1's code labels that state there were once two layers of objects in the game.
Here are some of the Sonic 1 references (ported to C). The name of the second object layer was officially Z
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Off topic: I did discover the name of the queued/buffered compressed art in the labels as well. The name is divdevwk.
Nice. Where did you find these names?
The two games have a lot of similarities with one another, so it's understandable they share the same symbol names too.
Yes, it was a matter of reading disassemblies side by side. The Gamecube port of Sonic CD doesn't do any queueing, but it does have most labels matching Sonic 1's (such as order of variables mostly equals the original RAM addresses if lucky). Then the Sega Saturn C dev documents match the port in its syntax/naming and structure, so things started to get pretty clear at one point. But it was the port of a boss that made all the difference (I think it was one of the Tidal Tempest bosses), as it still had the queue table index matching the Sega CD one. After that, I think some of the labels from the earliest Sonic 2 ROM made much more sense.
So
divdevwk IS the name of the RAM area $FFF680 ($60 in size), and that area (work) contains a queue list of the patterns to decompress into VRAM, mostly it is used for knowing where it left off last frame, so it could continue the work this frame. The system is not flawless as it contains bugs that are visible in Sonic 1 (such as overwriting patterns on some enemies and bosses if unlucky, like the Roller and Eggman's feets while jumping on the switch). Many Genesis games use the pattern compression, but I think only the Sonic games use this div dev queue (I could be wrong, also the name suggest div meaning it divides patterns into smaller pieces, or divides upload to VRAM over multiple frames). Also remember to not confuse this queueing with Sonic 3's LZ queueing/buffering of levels and art as that was new for Sonic 3 and was more effective (the name for that one is unknown, and so are the names of the all three compressions).
So with labels from Sonic CD, labels from S&K Collection, and very early Sonic 2 labels, as well as the Sega Saturn C devkit docs, names and the structure of the code got pretty clear.
As for music theories, I think most of them were blown away with the release of Masato Nakamura's Sonic the Hedgehog 1 & 2 Soundtrack album.
And to be a little bit on topic, I LOVE the early Sonic 1 art style. It is still pretty clear that Sonic 1's art style was kept from beginning of the development until the final release, and that is impressive.
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