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Task/Brownian-tree/FutureBasic/brownian-tree.basic

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+// Brownian tree
+//https://rosettacode.org/wiki/Brownian_tree
+
+/*
+A Brownian tree is built with these steps:
+first, a "seed" is placed somewhere on the screen.
+Then, a particle is placed in a random position of the screen,
+and moved randomly until it bumps against the seed.
+The particle is left there, and another particle is placed in a random position
+and moved until it bumps against the seed or any previous particle, and so on.
+
+*/
+
+
+begin globals
+
+  _w = 400 // window size
+  short w = _w
+  bool pixelUsed(_w ,_w )
+  short x, y , Oldx, Oldy
+  cgRect TheRect
+  short Edge
+  long SpeckleCount
+  short MainColor,SpeckleColor
+  bool GreenGreen,WhiteWhite,WhiteIndigo,WhiteMagenta,GreenIndigo,CyanBlue
+  bool SeedPlanted
+  long count
+
+
+  // Color Options
+  GreenGreen = 0
+  GreenIndigo = 0
+  WhiteIndigo = 1
+  WhiteWhite = 0
+  WhiteMagenta = 0
+  CyanBlue = 0
+
+  if GreenGreen then MainColor = _ZGreen : SpeckleColor = _ZGreen
+  if WhiteWhite then MainColor = _ZWhite : SpeckleColor = _ZWhite
+  if WhiteIndigo then MainColor = _ZWhite : SpeckleColor = _zSystemIndigo
+  if WhiteMagenta then MainColor = _ZWhite : SpeckleColor = _zMagenta
+  if GreenIndigo then MainColor = _ZGreen : SpeckleColor = _zSystemIndigo
+  if CyanBlue then MainColor = _zCyan : SpeckleColor = _zBlue
+
+end globals
+
+_Window = 1
+window _Window, @"", ( 0, 0, _w, _w ), NSWindowStyleMaskTitled  + NSWindowStyleMaskMiniaturizable
+
+windowcenter(_Window)
+WindowSetBackgroundColor(_Window,fn ColorBlack)
+
+local fn ClearPixelArray
+  cls
+
+  short row,col
+  for row = 1 to 400
+    for col = 1 to 400
+      pixelUsed(row,col) = NO
+    next
+  next
+
+
+  SpeckleCount = 0
+
+  Edge = _w
+  /// place seed in the middle
+  pen -1
+  oval fill (w/2,w/2,5,5), MainColor
+  x = w/2
+  y = w/2
+  pixelUsed(x,y) = YES
+
+  Oldx = x
+  Oldy = y
+  count = 0
+  SeedPlanted = _true
+
+end fn
+
+
+local fn DrawPixels
+
+  // Set New Random particle location
+  if SeedPlanted = _false
+    do
+      x = rnd(Edge)
+      y = rnd(Edge)
+    until pixelUsed(x,y) = NO
+  end if
+
+  SeedPlanted = _false
+  short xBack, yBack
+  xBack = x
+  yBack = x
+
+
+  // Find a location for the new particle
+  do
+
+    Oldx = x
+    Oldy = y
+
+    // set x and y within plus or minus 15 pixels of x or y
+    x += RND(3) - 2
+    y += RND(3) - 2
+
+    // prevent results that are not within 15 pixels of Oldx and Oldy
+    if x <= 0 then x = xBack : y = yBack
+    if y <= 0 then y = xBack : y = yBack
+    if x > Edge then x = xBack : y = yBack
+    if y > Edge then y = xBack : y = yBack
+
+  until pixelUsed(x,y) = YES
+
+
+  // Draw the new particle but protect the margin on the edge
+
+  if Oldx > 15 && Oldx < Edge - 15 && Oldy > 15 && Oldy < Edge - 15
+    SpeckleCount ++
+
+    pen -1
+    if SpeckleCount < 200
+      oval fill (Oldx,Oldy,1,1), MainColor
+    else
+      oval fill (Oldx,Oldy,2,2), SpeckleColor
+      SpeckleCount = 0
+    end if
+
+    pixelUsed(Oldx,Oldy) = YES
+    xBack = x
+    yBack = y
+    count ++
+  end if
+
+
+  if count > 10000
+    CFStringRef ReturnedKey
+    ReturnedKey = Inkey %(90,1),@"Any key for another one. Q to quit"
+    if fn StringContainsString(ReturnedKey, @"q") then end
+    if fn StringContainsString(ReturnedKey, @"Q") then end
+    fn ClearPixelArray
+  end if
+
+
+end fn
+
+
+fn ClearPixelArray
+
+fn AppSetTimer( .000001, @Fn DrawPixels, _true )
+
+handleevents