Hi there!
Shrek wrote:
I attach the code, and the place where all trouble began is commented
"HERE BEGINS THE PROBLEM".
Erik wrote:
When in doubt, don't guess at the cycles. Count them. Here's your code
with cycle counts added. You can see it's running a total of 92 cycles
per loop iteration, which is of course over the limit of 76. You can
also see that the version without the UFO ran right up to 71 cycles, so
adding anything to that would make it spill over.
Also, when looking at the code, I think the main problem is, that its
using sprite code to do missiles. Drawing a missile is a way simpler
thing, there's various shortcuts to draw it, depending on it's height.
In Seawolf I draw them using the illegal opcaode DCP:
LDA #3
DCP torpedoyPos
ADC #2
STA ENABL
And in Star Fire I use the stack trick:
LDX #$1F ; Set stack outside loop
TXS
...
LDY vline ; Draw both missiles and ball
CPY yposBackup+2 ; inside loop
PHP
CPY yposBackup+1
PHP
CPY yposBackup
PHP
...
LDX #$FF ; Restore stack outside loop
TXS
There's more methods hidden in the archive, specialized to diverse
situations or heights of missiles.
Greetings,
Manuel
