> sunset
> lda rbow,x ;6 draw the sunset
> sta COLUBK ;3
> lda mount,x ;6 draw the mountains
> sta PF0 ;3
> sta PF1 ;3
> sta PF2 ;3
> sta WSYNC ;3
> dex ;2
> bne sunset ;3
I think that it is a good habit to put the graphic registers-loading
instructions immediately after the STA WSYNC.
When I'm working on the kernel, I usually think in the following way...:
(..drawing n-th scanline..)
- near the end of the scanline, prepare something for the next... (LDA,
LDY, LDX..)
- STA WSYNC (start of (n+1)th scanline)
- finish preparing things if you couldn't do everything before
- load the registers (STA, STY, STX...) hopefully BEFORE they're read by
the TIA for display
This isn't really necessary for a simple program as above, but when yor
kernel
will be more complex thinking in this way could become important (IMO).
> As you can see, the background colour values are different for each line
> but the mountains repeat every two lines. This is what makes them look
> blocky. I tried it every one line, but then the mountains don't
> look as "majestic".
Ok, if you're happy, we are happy... :)
What about some slowly moving clouds?
> Incidently, the first time I ran this I forgot the WYSNC. The effect was
> quite interesting. It was changing the background colours and playfield
> graphics in mid scanline. Very interesting effect. One of those things I
> stuck away in my "to be exploited later" file. ;)
Boys, how many interesting things I've done _by chance_.
Here's the background music in Oystron:
LDA #6
STA AUDC1
LDA FRAMEC
ASL
ADC CURRNMY
LSR
STA AUDF1
LDA #2
STA AUDV1
FRAMEC is a counter with a step of 5... 0,5,10,15.. CURRNMY is the id of
the current enemy (0-13). Do you think that I was really looking for music
when I wrote this code? ;)
P.
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