Bad idea: build a captcha library that embeds DOSBox so it can make you beat levels/puzzles from DOS games to continue.
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@foone Or for the non-gamers: “Edit these CONFIG.SYS and AUTOEXEC.BAT files so that you have both CD-ROM access and mouse driver working, while also having 600KB of available conventional memory.”
We’d need anti-cheat to prevent the use of MEMMAKER though…
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step up: find the fade out.
see the game fades out when you go into a door. find where that code is, then see what gets called next.
finding a fade out should be easy: look for when they reprogram the VGA palette registers to dim every color to black.
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@gh oh that'd be fun.
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found 5 places the palette is reprogrammed
and all are in overlays. ugh.
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OKAY realistically this is a game that features several different games you can play, and games between games. they're just gonna make each one a separate overlay.
so I need to figure out how it shifts overlays and how to track which overlay is active
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looks like the separate game engines are called puzzler, electric, and simple.
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I love when games use __FILE__ in their assertions. please tell me all your filenames please
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can I not set an I/O breakpoint in dosbox-x's debugger? I forget.
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@foone some of these could probably do double duty as age verification challenges .
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@enno mean
but yeah, clearly. -
oh sweet laser jesus I found the upload palette function and THEY UNROLLED IT
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why do:
for(int i=0;i<256;i++){
upload_color(i,palette[i]);
}when you can do
upload_color(0,palette[0]);
upload_color(1,palette[1]);
upload_color(2,palette[2]);
upload_color(3,palette[3]);
upload_color(4,palette[4]);
upload_color(5,palette[5]);and just repeat 251 more times
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the worst part is that this was done with a compiler from 1991 so there's no way it unrolled the loop itself. they did this manually
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@foone Any idea why? I have extremely little experience with programming in that era, but I remember that code size was always a serious concern ... so unrolling it sounds like a bad idea, unless they really needed it for performance.
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@saua it runs slightly faster. like a couple cycles per "iteration".
This is aiming at CPUs so slow that that might matter
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No compiler flags that would do this?
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oh that's cute. their set_palette function takes two arguments: a pointer to the palette, and a number of extra palettes to apply.
so they could set up an array of palettes in decreasing brightness, and just do set_palette(&fade_pallets[0], 64) to go through them.
but the same function is a regular one-time set_palette if you just pass 1 for the second argument.
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@simonzerafa in 1991? I don't think so. Not a for loop this big.
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"hey ghidra what calls set_palette?"
"I don't know! you're in 16bit segmented mode! pointers are MEANINGLESS
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ahh, nope! I misidentified it.
the second parameter on set_palette is how many frames to set it for.
The same palette gets set.it vsyncs every time so this is a set_palette that's also a timing function
