Hi there!
Just had some more thoughts about playfield destruction.
When you have the PF refelected like this:
PF0 PF1 PF2 PF2 PF1 PF0
The (r)eversed vs. (u)nreversed bit readings should be like
PF0 PF1 PF2 PF2 PF1 PF0
u r u r u r
So if you use PF1 and PF2 _only_, you have "r u" repeating twice!
That means, you should get away with one 16 byte AND table, starting
reversed:
disintigratetab
.byte %11111110
.byte %11111101
.byte %11111011
.byte %11110111
.byte %11101111
.byte %11011111
.byte %10111111
.byte %01111111
.byte %01111111
.byte %10111111
.byte %11011111
.byte %11101111
.byte %11110111
.byte %11111011
.byte %11111101
.byte %11111110
Now you should be able to erase the "right" block horizontally for _any_
possible position with code as simple as:
LDA xpos
LSR
LSR ; divide by 4
SEC
SBC #$04 ; skip PF0
AND #$0F ; limit to our table range
TAX
LDA disintigratetab,X
Cool, or? :-)
Ah, and for your ball it looks like this, right:
x.##..
.####.
######
.####.
..##..
The x is indicating the x/y coordinates where it's drawing starts.
Now, in case of a collision, you have to move the x around, according to
your movement direction, for example, when moving straight right:
y.##..
.####.
#####x
.####.
..##..
you should add 5 to the x position and 3 to the y position. so you're not
checking which block is on the original coordinates (y), but which block
was hit by the rightmost spot of your ball...
Just ideas, hope they help... :-)
Greetings,
Manuel
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