Hi,
I don't know if anybody else has already looked into the Meltdown
code. I got curious because it doesn't work perfect on emulators.
The code is IMO quite sophisticated:
1. It uses selfmodifying code for kernel display!
2. It uses flicker for some quite effective anti-aliasing
3. Is uses a trick which is new too me to display two wide spaced
AND double size players! Here is the code, which I suppose is
responsible for that:
009e: ldx #04 ; two copies wide
00a0: lda #35 ; double sized player
00a2: stx NUSIZ0
00a4: sta NUSIZ0
00a6: lda #15 ; double sized player
00a8: sty GRP0
00aa: stx NUSIZ1
00ac: sta NUSIZ1
(AFAIK you can ignore the bits for missile size)
So by switching the register to two wide copies and *immediately*
after set switching to double size player, you seem to be able to
combine both settings. Isn't that cool?!?
Maybe it is also possible to combine other settings (e.g. quad size player
and three copies wide) by using this trick. I'll start experimenting with
that when I return home.
Have fun!
Thomas
_______________________________________________________
Thomas Jentzsch | *** Every bit is sacred ! ***
tjentzsch at web dot de |
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