sprite duplication issue

[jotd]

Not sure it's a winuae problem but I think it is (cannot test on the real machine until september)

On my Pacman game sometimes ghosts are duplicated in the maze.

Ghosts use sprites. Each ghost has its own palette so I have to use sprites 0, 2, 4, 6 (not using odd sprites for now)

check video at https://eab.abime.net/showpost.php?p...9&postcount=81


a still pic where it happens too



I'm not using sprite reuse in the raster frame and I only move the sprites continuously and only when vertical pos is down the screen


I've zoned a "pacman.zip" where it shows too.


I'm at a loss with that issue. How could I accidentally trigger sprite reuse?

[ross]

You made the sprite taller that it should be.
If you set it as h=16 the successive words need to be 0 if do not want y-multiplexing

Considering that the last line of the sprite is zeroed perhaps the simplest thing is to use the EV coordinate that you now use -1.

[jotd]

holy crap, that fixed it (and I realize that I didn't read your post but applied some recipe that I read somewhere else but I didn't find logical

    dc.l    0
    incbin  "frightened_ghost_white_1.bin"
    dc.l    0,0    <--------------- added 2 longwords and the effect disappears

I don't know if I need 1 or 2 longwords... Sprite reuse is also completely obscure to me. As the various sprite images followed each other I suppose that the DMA fetched the data. So DMA doesn't care about the size and you have to put zero? that's strange What if there are zeroes in the sprite data?

(sorry for hijacking winuae thread, I'll ask for thread to be moved, can a mod move that thread to coders hardware/asm?)

many thanks!!!

[ross]

Originally Posted by jotd

I don't know if I need 1 or 2 longwords...

For the usual sprites FMODE=1x, 2 words.

Sprite reuse is also completely obscure to me. As the various sprite images followed each other I suppose that the DMA fetched the data.

Yes, and just by chance new y position for the 'new' sprite is > of end of the 'previous'.

So DMA doesn't care about the size and you have to put zero? that's strange

Sure DMA care of the size but it continue to work, so it fetches new POS/CTL values

What if there are zeroes in the sprite data?

Transparency

[Rotareneg]

You specify the start and stop lines in the control words, followed by the sprite data words for however many lines you've indicated the sprite is tall. It's the two words AFTER the end of the data words that matter. If they're not zeros it'll assume you're reusing the sprite and interpret them as control words for reusing that sprite, including new data as it doesn't just reuse the old data.