As we got Railroad Tycoon intro to load further, we encountered one PICT resource which was a bit different from the others: It was a version 2 picture, while all previous pictures in the same game were simple version 1 PICTs. It appears that when apple added support for the new version 2, they also added rudimentary system software patches to the old-style QuickDraw on “Classic” type macs to handle the new opcodes. Without support for these opcodes, the classic QD would just ignore picture data and display nothing.
The interesting part of these version 2 format patches is the fact, that it allows non-color QuickDraw to take PixMap data, and map it using a simple 50% threshold to either black or white in a regular monochrome bitmap. Also, any unsupported picture opcodes get ignored using the simple dummy StdOpcodeProc implementation for non-color QuickDraw. So, to make this type of pictures show, we had to implement all of this color mapping functionality, resulting in this:
Well, almost got it…just accidentally incremented a pointer twice during the color mapping loop. After quick fix, this is what we had: