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angelo-wf / LakeSnes

A SNES emulator, in C
MIT License
122 stars 15 forks source link

Firepower 2000 titlescreen, strange horizontal line #7

Open dinkc64 opened 1 year ago

dinkc64 commented 1 year ago

Hi, First, let me start off by saying that I've played nearly 100 games in your emulator and this is the only video-glitch I've come across - on top of that, I love what you're doing here! The problem I'm mentioning isn't even a big deal--just noticed it thought I'd mention it as it is not listed in the bugs.md file. The game Firepower 2000 has a strange horizontal line across the titlescreen, as seen here:

firepower2000

best regards,

angelo-wf commented 1 year ago

Can confirm. It being exactly one line could indicate some stray HDMA going wrong maybe? (the line also isn't fully black). Will have to look into it some more.

I will (also) add it to bugs.md for now.

dinkc64 commented 11 months ago

This is caused by rendering the line @ hPos 512. The game writes to the objsel register (ppu @ 0x2101) & selects a different bank at hPos 240 on line 128, so it ends up drawing an incorrect line. The sand/line in question comes from the sprites.