I'm trying to fit in a "library" all special efects that can be done (at least 90%) in hblank.
There's all the info i've gathered about this:
HBlank is 28 cycles long.
How to get to that 28 cycles:
MMC3 with IRQ or other mapper.
Sprite 0 hit and wait with timed code (only once per frame)
What can be done:
-Modify nametable via $2000
-Modify color intensify / grayscale via $2001
-Modify palette (only a few bytes though, could be used to change background colour)
-Change scrollX via $2005
-Change scrollXY via $2005/$2006
-Bankswitch chr via mapper
-Change mirroring via mapper
After that 28 cycles other operations can be done on irq that doesn't affect drawing.
Is that correct? Are there some pre/postrequisites to do this effects?
what else could be done?
There's all the info i've gathered about this:
HBlank is 28 cycles long.
How to get to that 28 cycles:
MMC3 with IRQ or other mapper.
Sprite 0 hit and wait with timed code (only once per frame)
What can be done:
-Modify nametable via $2000
-Modify color intensify / grayscale via $2001
-Modify palette (only a few bytes though, could be used to change background colour)
-Change scrollX via $2005
-Change scrollXY via $2005/$2006
-Bankswitch chr via mapper
-Change mirroring via mapper
After that 28 cycles other operations can be done on irq that doesn't affect drawing.
Is that correct? Are there some pre/postrequisites to do this effects?
what else could be done?