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Logarithmic spiral
Posted: Mon Jan 02, 2017 8:49 pm
by Dutchman
A logarithmic spiral, derived from the code for Archimedean spiral
viewtopic.php?f=20&t=1696
Code: Select all
'Logarithmic spiral, in polar coordinates
'by Dutchman, january 20
' --- constants
dphi=0.1 ' angular increment
a=0.1
b=0.1
GET SCREEN SIZE sw,sh
x0=sw/2 ! y0=sh/2
size=MIN(x0,y0)
' --- initiate graphics
GRAPHICS
GRAPHICS CLEAR 1,1,0.5
DRAW COLOR 1,0,0
DRAW SIZE 2
' --- initiate
DRAW TO x0,y0
' --- loop
DO
r=a*EXP(b*phi)
z=r*EXP(1i*phi)
DRAW LINE TO x0+REAL(z),y0-IMAG(z)
phi+=dphi
UNTIL ABS(z)>size
END
- logarithmic spiral.PNG (87.69 KiB) Viewed 2494 times
Re: Logarithmic spiral
Posted: Mon Jan 02, 2017 9:07 pm
by rbytes
Thanks, Dutchman.
Re: Logarithmic spiral
Posted: Tue Jan 03, 2017 1:14 am
by Operator
I like this, so an animated version had
to be included...
Code: Select all
'Logarithmic spiral, in polar coordinates
'by Dutchman, january 2017
' --- constants
dphi=0.1 ' angular increment
a=0.1
b=0.1
GET SCREEN SIZE sw,sh
x0=sw/2 ! y0=sh/2
SIZE=MIN(x0,y0)
' --- initiate graphics
GRAPHICS
GRAPHICS CLEAR 1,1,0.5
DRAW COLOR 1,0,0
DRAW SIZE 2
SPRITE 1 BEGIN sw,sh
SPRITE 1 END
' --- initiate
DRAW TO x0,y0
' --- loop
SPRITE 1 BEGIN
DO
r=a*EXP(b*phi)
z=r*EXP(1i*phi)
DRAW LINE TO x0+REAL(z),y0-IMAG(z)
phi+=dphi
UNTIL ABS(z)>SIZE
SPRITE 1 END
SPRITE 1 SHOW
'END
LOOP:
dang += 0.001
SPRITE 1 AT 0,0 ANGLE dang
GOTO LOOP
Re: Logarithmic spiral
Posted: Tue Jan 03, 2017 2:46 am
by sarossell
I am getting sleepy..........
