Crazy Balloon - 19th Nervous Breakdown

[Manuel Rotschkar <cybergoth@xxxxxxxx>]

Hi there!

So wow. Here I come, presenting you a binary that looks precisely like the 
one posted two days ago. All I did the last to days was freeing more 
cycles for the kernel. Now, the last binary had 10 free kernel cycles, and 
the current one has 17 :-)

How did I do that? Well, let's see what the old kernel did:

It was a 2LK drawing the balloon on both lines at 1LK precission, the PF 
on the first line at 6LK precission and the (enemy-)sprite on the second 
line with 2LK precission.
It also had a counter counting every single line to draw the balloon.

Now, I despreately needed more cycles, so what could I do?

I finally had an idea: To draw the balloon, I was doing something like 
this each scannline:

        LDA #BALLOON_HEIGHT-1
        DCP balloonOffset
        BCC SkipBalloon
        LDA (balloonmovPtr),Y
        STA HMP0
        LDA (balloonPtr),Y
        STA GRP0

Now, my basic idea was to do the draw/notdraw descision only once every 
two lines. That means I had to split all my sprite and HMOVE data into 
pairs of tables, so I could have two pointers:

First:
data .byte 1,2,3,4,5,6

Then:
data1 .byte 1,3,5
data2 .byte 2,4,6

So much the simple things. It also had the advantage that my counter now 
could live with counting every other scanline only.

So far so good. You'll notice a disadvantage of this method: You lose the 
positioning precission, as your scanline counter will only increase every 
other scannline. And here the nightmare began... ;-)

Well, in the end I succeeded geting my vertical precission back. Its 
gotten somewhat complicated though. When having the double resolution 
outside the kernel, you need to shift your data pointers every other 
"position" and swap them, also making your data "one" bigger and pad it 
with zeros like in:

data1 .byte 1,3,5,0
data2 .byte 0,2,4,6,0

Now for an even height, you just start normal with data1 and shift the 
pointer for data 2 by one, so you get this in the first frame:

<1> <2> <3> <4>
1,2,3,4,5,6,0,0

For the second frame, you need to swap your pointers:
<1> <2> <3> <4>
0,1,2,3,4,5,6,0

Ah, well... anyone following me? At least the bin shows that it's working 
;-)
Didn't even cost much ROM, since now my divideby3 table is only half as 
big, as I'm only counting every other scannline now. (Actually, thinking 
of it, it originally was a divideby6 table anyway... ;-))

Ok, whatever, Now I can go on with the project... :-)

Greetings,
Manuel

Attachment: crazy.zip
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