RosettaCodeData/Task/Mandelbrot-set/Sinclair-ZX81-BASIC/mandelbrot-set-3.basic
2023-07-01 13:44:08 -04:00

20 lines
486 B
Text

OPTION STRICT
VAR XP, YP, X, Y, X0, Y0, X2, Y2
VAR NEXT_X, IT, C
FOR XP = -200 TO 199
FOR YP = -120 TO 119
X = 0: Y = 0
X0 = XP / 100: Y0 = YP / 100
IT = 0
X2 = X * X: Y2 = Y * Y
WHILE X2 + Y2 <= 4 AND IT < 100
NEXT_X = X2 - Y2 + X0
Y = 2 * X * Y + Y0
X = NEXT_X
X2 = X * X: Y2 = Y * Y
INC IT
WEND
IF IT == 100 THEN C = 0 ELSE C = IT
GPSET XP + 200, YP + 120, RGB((C * 3) MOD 200 + 50, FLOOR(C * 1.2) + 20, C)
NEXT
NEXT