I tried every variation of color code I could think of, I even split the colors into each of its components but never thought to subtract 5 from those values, if on the off chance I had, I would have found it. I would love to tell you I was really clever about my method of figuring this out and that I used some sort of logic but that would be a lie. To find it I simply selected huge portions of the file in a hex editor, filled them with zeros and ran the game to see what had changed. Sometimes this broke the game completely, most times it glitched the game with some hilarious outcomes. Eventually on one of these attempts, nothing had changed except all of the 3D objects disappeared, this made me think that I must have found the section which draws these 3D objects. Then I just whittled it down less and less till all that changed were the colors of the objects. That's all I know.
The palette for the 1-8 rollers is just before the falling wall palette.
I have nothing to do so I wrote them all down for you. For some reason the top of the falling wall has three colors on it but you can only see two because two of the colors are the same.
001a7d40 - 001a7d6f
4 different sides as only 4 can be seen at once
001a7d40 = main color 1
001a7d44 = lines 1
001a7d48 = lines on each side 1
001a7d4c = main color 2
001a7d50 = lines 2
001a7d54 = lines on each side 2
001a7d58 = main color 3
001a7d5c = lines 3
001a7d60 = lines on each side 3
001a7d64 = main color 4
001a7d68 = lines 4
001a7d6c = lines on each side 4
|1-4 falling walls:|
001a7d88 = main color
001a7d8c = lines
001a7d90 = shadow
001a7d70 = top of wall left 3/4
001a7d74 = top of wall right 1/4
001a7d78 = top of wall sides
The colors are pretty simple to work out just separate the BGR components and subtract 5 from each. If it is less than 0 set it to 0. so 0x1D91 = 0x02070c
Are there any other 3D objects? I thought the spinning platforms before the boss in 2-4 were 3D but they don't seem to darken like the others.
Some pics from when I was figuring this out:
I'll check out the emu, It might give my ears a little rest.