UnderwareDESIGN

Hi!

The example shows the drawing of Mandelbrot fractal.

You must wait a little
(KPix/sec is coming after second turn)

Greetings
stef

[pbcode]
; PROJECT : appleman
; AUTHOR  : stef
; CREATED : 21.11.2005
; EDITED  : 26.01.2013



Global maxiter#=64


w# = 640   
h# = 480   


openscreen  w#, h#, 32, 1
   xstart# =  -2.025
   ystart# = -1.125
   xende# = 0.6
   yende# = 1.125

   fac#=0.99

  print "Working"
 
  Sync
 
do
      Cls 0
      xende# = xende#*fac#
      xstart#=xstart#*fac#
      ystart#=ystart#*fac#
      yende#=yende#*fac#
      xzoom# = (xende# - xstart#) / w#
      yzoom# = (yende# - ystart#) / h#

      mandelbrot(w#, h#, xstart#, ystart#, xzoom#, yzoom#)

      thistime = timer()
      Print  Str$(Int(w#*h# / (thistime-lasttime))) + " Kpix/sec"
      lasttime=thistime
      sync
loop
End


Function mandelbrot(w1#, h1#, xstart#, ystart#, xzoom#, yzoom#)
     
  For y = 0 To h1#-1
      lockbuffer

      YValue#=ystart# + yzoom# * y
      For x = 0 To w1#-1

            h# = DotsColor(xstart# + xzoom# * x, yValue#)

             If h# <> old#
               b# = 1.0 - h# * h#
               col = HSBtoRGB(h#, 0.8, b#)
               old# = h#
            EndIf
     
            dotc x,y,col
         Next
      unlockbuffer 
   Next
     
EndFunction


function DotsColor(xval#, yval#)

While j# < maxiter# and abs(r#)<4.0
j#=j#+1.0
m# = r# * r# - i# * i#
i# = 2*r# * i# + yval#
r# = m# + xval#

endwhile

j# = j#/ maxiter#

EndFunction j#


function HSBtoRGB(hue#, saturation#, brightness#)

  ;If brightness# = 0 Then exitfunction col1= 0
  ;If saturation# = 0 Then exitfunction col1= RGB(brightness#*255, brightness#*255,brightness#*255)

   If hue#  < 1.0/6.0
      dom# = hue#
      red#   = brightness#
      blue#  = brightness# * (1.0 - saturation#)
      green# = blue# + (brightness# - blue#) * dom# * 6
   Else
      If hue#  < 2.0/6.0
         dom# = hue# - 1.0/6.0
         green# = brightness#
         blue#  = brightness# * (1.0 - saturation#)
         red#   = green# - (brightness# - blue#) * dom# * 6.0
      Else
         If hue#  < 3.0/6.0
            dom# = hue# - 2.0/6.0
            green# = brightness#
            red#   = brightness# * (1.0 - saturation#)
            blue#  = red# + (brightness# - red#) * dom# * 6.0
         Else
            If hue#  < 4.0/6.0
               dom# = hue# - 0.5
               blue#  = brightness#
               red#   = brightness# * (1.0 - saturation#)
               green# = blue# - (brightness# - red#) * dom# * 6.0
            Else
               If hue#  < 5.0/6.0
                  dom# = hue# - 5.0/6.0
                  blue#  = brightness#
                  green# = brightness# * (1.0 - saturation#)
                  red#   = green# + (brightness# - green#) * dom# * 6.0
               Else
                  dom# = hue# - 5.0/6.0
                  red#   = brightness#
                  green# = brightness# * (1.0 - saturation#)
                  blue#  = red# - (brightness# - green#) * dom# * 6.0
               EndIf
            EndIf
         EndIf
      EndIf
   EndIf
   col1= RGB(red# * 255.0, green# * 255.0, blue# * 255.0)

endFunction col1


[/pbcode]