Quote:
Originally Posted by mydma
But am I right in understanding here that because BPL0DAT is written at the start of a raster line, then writing to SPR0DATA will show the sprite even though bitplane dma is disabled?
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The first write activate sprites for the full line (actually it's called BPL1DAT).
Warning, cannot be done too soon.
Quote:
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I had already tried writing $ffff to SPR0DATA at the top of the frame with sprite dma disabled to cause a vertical bar but it obviously only showed where bitplane dma was actually enabled.
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Is the write to BPL1DAT (DMA, Copper, even CPU) that activate the buffered output for all the bplanes. At the fine position specified in BPLCON1.
Also a non-aligned DDFSTRT join the equation, especially in fetch modes higher than OCS/ECS (your $24 is one of these special cases.. try to change BPLCON1
).
This can open you to very interesting effects (the famous BPLCON1 zoom trick to do an hw line shrink).
EDIT: gosh, just noticed that Dan is in this thread, ask him for BPLCON1 trick
First effect (~25"):
[ Show youtube player ]