Here is the Mandelbrot version of my Julia Set program, coded in assembly. Again, many thanks to the forum users here for their guidance, as well as the many YouTubers with their excellent tutorials on 6502 assembly language. It's a lot faster than the BASIC version, but nevertheless, benefits from being run in warp mode.
Now in colour, with thanks to: VERA Overview (8bitcoding.com)
NEW VERSION NOW WITH MOUSE CONTROLS!
When the image has finished rendering, click the left mouse on the area of the screen you wish to zoom in to.
To change the detail settings (cycle between Low, Med, High) click the right mouse button.
Poke around in the old version...
Try copying and pasting the following groups of POKEs to explore further (not all at once, just each paragraph in turn!):
POKE $D6B,$19:POKE $D6A,$64:REM FX=6500
POKE $D6D,$13:POKE $D6C,$54:REM FY=4948
POKE $D6E,$00:POKE $D6F,$FF:REM FX=POS,FY=NEG
POKE $D7B,$00:POKE $D7A,$01:REM STEP=1
POKE $D7C,$FF:REM ITERATIONS=255
SYS2061
POKE $D6B,$0F:POKE $D6A,$A0:REM FX=4000
POKE $D6D,$00:POKE $D6C,$00:REM FY=0
POKE $D6E,$FF:POKE $D6F,$FF:REM FX=NEG,FY=NEG
POKE $D7B,$01:POKE $D7A,$F4:REM STEP=500
POKE $D7C,$FF:REM ITERATIONS=255
SYS2061
POKE $D6B,$0F:POKE $D6A,$878:REM FX=3960
POKE $D6D,$03:POKE $D6C,$E8:REM FY=1000
POKE $D6E,$FF:POKE $D6F,$FF:REM FX=NEG,FY=NEG
POKE $D7B,$00:POKE $D7A,$32:REM STEP=50
POKE $D7C,$FF:REM ITERATIONS=255
SYS2061
To use the POKES above in the web emulator, first click the X in the top right corner of the web emulator. Paste the POKES above that you want to use in to the text field to the left, replacing what's already in there, then click the Run button.
Individual addresses that can be poked:
$D6A 30 75 .word 30000 ; FX
$D6C A8 61 .word 25000 ; FY
$D6E FF .byte $ff ; FX SIGN ff = negative
$D6F FF .byte $ff ; FY SIGN ff = negative
$D7A A8 61 .word 25000 ; STEP (lower=higher zoom)
$D7C 10 .byte $10 ; ITERATIONS
Old poke codes for the colour PETSCII version:
step: POKE $0D3D e.g. 50 for a step of 0.05
(smaller number, higher zoom)
iterations: POKE $0D3F e.g. 30 iterations about right, higher = slower
start x: POKE $0D2F, normally 8 (for -0.8) - nicely centred at low zoom
start y: POKE $0D31, normally 12 (for -1.2) - again centred at low zoom
Old poke codes for the PETSCII version:
step: POKE $0cff e.g. 50 for a step of 0.05
(smaller number, higher zoom)
iterations: POKE $0d01 e.g. 30 iterations about right, higher = slower
start x: POKE $0cf1, normally 8 (for -0.8) - nicely centred at low zoom
start y: POKE $0cf3, normally 12 (for -1.2) - again centred at low zoom
You Tube video of this in action:
Commander X16 - 6502 assembly demo - Mandelbrot set - YouTube
Commander X16 - Fractal Zoom Demo - 6502 Assembly - YouTube
Now with mouse controls!
