프랙탈로 나무 쓰기

코드

{sin, cos, PI} = Math

drawLine = (ctx, p1, p2) ->
  ctx.beginPath();
  ctx.strokeStyle = 'gray'
  ctx.moveTo(p1.x, p1.y);
  ctx.lineTo(p2.x, p2.y);
  ctx.stroke();

drawTree = (
  ctx     # canvas context
  x1, y1  # position
  len     # length of node
  stand   # current dir
  depth   # recursion count
) ->
  rl = Math.abs(0.5 - Math.random()) * len
  x2 = x1 + rl * cos(stand)
  y2 = y1 + rl * sin(stand)
  drawLine(ctx, {x: x1, y: y1}, {x: x2, y: y2})
  if depth > 0
    diffdir = Math.random() * PI / 6
    drawTree(ctx, x2, y2, len, stand + diffdir, depth-1)
    drawTree(ctx, x2, y2, len, stand - diffdir, depth-1)

window.addEventListener 'load', ->
  canvas = document.createElement 'canvas'
  canvas.width=800
  canvas.height=600
  document.body.appendChild(canvas)
  ctx = canvas.getContext('2d')
  for x in [1..30]
    drawTree(ctx, 600*Math.random(), 400*Math.random(), 20, -PI/2, 8)

결과