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Rocket Knight Adventures Compression

Discussion in 'Engineering & Reverse Engineering' started by StephenUK, Mar 4, 2015.

  1. StephenUK

    StephenUK

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    Quackshot Disassembly
    Over the last 3 months I have been working on a disassembly of Rocket Knight Adventures and seem to be making decent progress. Just recently I appear to have located the main decompression routine, responsible for art compression at a minimum and possibly other things, and ran a quick test to make sure I had located what I suspected I had. A quick RTS replacement and run later, and sure enough all the compressed art failed to load, the uncompressed art loaded fine and the layouts remained intact (minus the art of course).

    Now here's where I hit a problem. As far as making tools for compressing and decompressing go (or anything involving modern languages for that matter), I have no experience or knowledge whatsoever. The question is, does anybody have the experience and interest to make a codec tool for this game, and if so, what kind of information is actually needed for it to be possible?
     
  2. Hivebrain

    Hivebrain

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    This is the decompression routine at $5FE4 (US ROM) you're talking about?

    There's also another decompression routine at $4A78 (US ROM) which is apparently only used for the Konami logo tilemap data.
     
  3. StephenUK

    StephenUK

    Liquor in the front, poker in the rear Tech Member
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    Quackshot Disassembly
    I'm assuming it is the same one as at $5FE4 in the US ROM, however I am disassembling the EU ROM due to personal preference and having the ROM to hand, and the decompression routine in that starts at $6040. I'll have a look at the decompression routine for the Konami logo, which appears to be at $4A7C in the EU ROM.