tandy put their sound chip on the 1A interrupt?
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if definitely decompresses and then blits the image as two parts, which aren't evenly sized, and it starts from the bottom
I think they're just trying to keep their RAM usage down by not having both halves in memory at once
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I think they're just trying to keep their RAM usage down by not having both halves in memory at once
wait is this image format vertically interlaced!?
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wait is this image format vertically interlaced!?
It loads the half-width version, then a few functions later, it's been replaced with a full-width version.
Strange!
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It loads the half-width version, then a few functions later, it's been replaced with a full-width version.
Strange!wait no, the colors are wrong... I bet I'm seeing it decompress the binary, but that's using the full width of the bytes. it then gets expanded out to a 16-color image.
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wait no, the colors are wrong... I bet I'm seeing it decompress the binary, but that's using the full width of the bytes. it then gets expanded out to a 16-color image.
well the good news is that I think I've found the decompress_image function. the bad news is that now I have to reverse engineer it
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well the good news is that I think I've found the decompress_image function. the bad news is that now I have to reverse engineer it
it's currently doing the obvious thing for a decompressor to do:
write the byte 04 every 69 bytes -
it's currently doing the obvious thing for a decompressor to do:
write the byte 04 every 69 bytesoh sweet jesus, that's the left two pixels of the image.
it's loading the image vertically!at least it's top to bottom.
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oh sweet jesus, that's the left two pixels of the image.
it's loading the image vertically!at least it's top to bottom.
yeah, doom did that too, but Doom was a 2.5D image that had to do pseudo-raycasting.
THIS GAME DOES NOT
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yeah, doom did that too, but Doom was a 2.5D image that had to do pseudo-raycasting.
THIS GAME DOES NOT
it allocates a 1024 byte buffer, then makes a pointer to the end of it, minus -0x42?
why would you need a link to the end of a new, freshly cleared buffer, minus 62?
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it allocates a 1024 byte buffer, then makes a pointer to the end of it, minus -0x42?
why would you need a link to the end of a new, freshly cleared buffer, minus 62?
I think the memory allocation system here is that every malloc returns 2 extra bytes, which is a pointer to the previous block.
unless it's an odd number, in which case it's a free block. and pointer to the previous block, once you make it even again -
I think the memory allocation system here is that every malloc returns 2 extra bytes, which is a pointer to the previous block.
unless it's an odd number, in which case it's a free block. and pointer to the previous block, once you make it even againI hate dealing with the internals of memory allocation systems. I prefer to leave that to smarter people than me
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I hate dealing with the internals of memory allocation systems. I prefer to leave that to smarter people than me
You see this little About dialog box? Guess how many times the DrawText function is called?
Once! and just to draw "Where in the World is Carmen Sandiego?".
The rest of the text is draw elsewhere, and I have no idea why.
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You see this little About dialog box? Guess how many times the DrawText function is called?
Once! and just to draw "Where in the World is Carmen Sandiego?".
The rest of the text is draw elsewhere, and I have no idea why.correction: it calls it once to draw "Where in the World is Carmen Sandiego?" but that's unrelated to the one on screen WHAT?
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correction: it calls it once to draw "Where in the World is Carmen Sandiego?" but that's unrelated to the one on screen WHAT?
Ahh, it's using a different version of the DrawFont call: DrawFontN
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Ahh, it's using a different version of the DrawFont call: DrawFontN
the only problem with using Ghidra to hack children's games instead of, like, Serious Things like firmwares or malware or whatever, is sometimes you have to make a label named NUM_MOUNTAIN_CLIMBING_HINTS
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the only problem with using Ghidra to hack children's games instead of, like, Serious Things like firmwares or malware or whatever, is sometimes you have to make a label named NUM_MOUNTAIN_CLIMBING_HINTS
(the number of mountain climbing hints is 3, by the way)
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(the number of mountain climbing hints is 3, by the way)
I think I accidentally hacked my debugger
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I think I accidentally hacked my debugger
It has a surprisingly robust UI engine. I swapped from BoldFont to SmalFont and the menu adapted perfectly.
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It has a surprisingly robust UI engine. I swapped from BoldFont to SmalFont and the menu adapted perfectly.
The game loads the BoldFont first, then the SmallFont, then the NormalFont.
Annoyingly this isn't how they're laid out in memory:
It's SmallFont, then BoldFont, then NormalFont -
The game loads the BoldFont first, then the SmallFont, then the NormalFont.
Annoyingly this isn't how they're laid out in memory:
It's SmallFont, then BoldFont, then NormalFontWeirdly, swapping the NormalFont for the SmallFont causes the printer text to be VERTICAL, for reasons I do not remotely understand!
