;Draws a bumpy line between two xy points
;BlitzPlus! 1.44
;Thomas A. Stevenson (TAS)
;10-27-2008
Graphics GadgetWidth(Desktop()),GadgetHeight(Desktop())
seed=MilliSecs()
SeedRnd(seed)
Color 255,0,0
BrokenLine(100,100,400,300,9,100,0.70)
Text 440,300,"0.70 Not enough damping"
SeedRnd(seed)
Color 0,255,0
BrokenLine(100,200,400,400,9,100,0.60)
Text 440,400,"0.60"
SeedRnd(seed)
Color 0,0,255
BrokenLine(100,300,400,500,9,100,0.50)
Text 440,500,"0.50"
SeedRnd(seed)
Color 255,0,255
BrokenLine(100,400,400,600,9,100,0.40)
Text 440,600,"0.40"
Text GadgetWidth(Desktop())/2,GadgetHeight(Desktop())-100,"Press Any key",1,1
Flip
While GetKey()=0: Wend
Function BrokenLine(x0%,y0%,x2%,y2%,d%,r%,damp#)
;d parameter determines how many sub-segments are create, i.e. 2^d segments
;r is a roughness parameter in pixels
;damp# decrease r for sublines
If d>0 Then
;calculate new mid point x1,y1 with random offset
;and break line into two lines
;x1,y1 is perpendicular to orginal line and at
;random distance of r1 where: -r>=r1=<r from line
;Note if the dy/dx is the slope of a line a
;perpendicular line has a slope of -dx/d
d=d-1
dx=x2-x0
dy=y2-y0
r0=Sqr(dx*dx+dy*dy)
r1=Sqr(Rand(r,r*r))
;r1/r0 is a scale factor so that x2,y2 is r distance from the line
If r0>1 Then dx1=dx*r1/r0 Else dx1=1
If r0>1 Then dy1=dy*r1/r0 Else dy1=1
;dir is used to make x2,y2 randomly above or below line
dir=1-2*(Rand(10)>5)
;new mid point halfway on line + random perpendicular offset r
x1=(x0+x2)/2+dy1*dir
y1=(y0+y2)/2-(dx1*dir)
;require to get a bumpy line rather than a mess
;values between 0.30 and 0.65 probably work best
r=r*damp#
BrokenLine(x0%,y0%,x1%,y1%,d%,r,damp#)
BrokenLine(x1%,y1%,x2%,y2%,d%,r,damp#)
Else
Line x0%,y0%,x2%,y2%
EndIf
End Function |
