Hi all,
I am working on a nes emulator from scratch (mainly for learning purposes) in javascript. I have build the cpu allready (it's seems to be Ok and have passed a few test for llegal opcodes); i have build the ppu too (almost 80%), and some games are fully playable right now (like Donkey Kong). But I have found some extrange behaviour in some games like 'Mario Bros' (not 'Super Mario Bros') or 'Pac-Man'. All seems to work properly, but the sprites (Mario and turtles), falls without collides with the background. I have check the sprite 0 hit collision on PPUSTATUS register and it's set to 0x40 (six bit) when a collision is detected between sprite and background (I have force the collision bit on this register all the time for test purposes, but nothing changes)... I wonder if there is another collision system / register that I am not implementing or if my sprite 0 hit collision is not implemented correctly.
I am stuck on that right now, any help will be appreciated.
Thanks in advance,
Regards,
I am working on a nes emulator from scratch (mainly for learning purposes) in javascript. I have build the cpu allready (it's seems to be Ok and have passed a few test for llegal opcodes); i have build the ppu too (almost 80%), and some games are fully playable right now (like Donkey Kong). But I have found some extrange behaviour in some games like 'Mario Bros' (not 'Super Mario Bros') or 'Pac-Man'. All seems to work properly, but the sprites (Mario and turtles), falls without collides with the background. I have check the sprite 0 hit collision on PPUSTATUS register and it's set to 0x40 (six bit) when a collision is detected between sprite and background (I have force the collision bit on this register all the time for test purposes, but nothing changes)... I wonder if there is another collision system / register that I am not implementing or if my sprite 0 hit collision is not implemented correctly.
I am stuck on that right now, any help will be appreciated.
Thanks in advance,
Regards,