Contents

# http://processing.org/learning/topics/tree.html
# by Joe Holt

def setup
  size 200, 200
  color_mode RGB, 1
  frame_rate 30
  smooth
  @x = 0.0
  @dx = width / 100
  @start_time = Time.now
  @frame_time = nil
end

def draw
  t = Time.now
  if @frame_time
    fps = 1.0 / (t - @frame_time)
    # printf "%0.1f fps\n", fps    
  end
  @frame_time = t
  
  background 0
  stroke 1, 1, 1
  # Let's pick an angle 0 to 90 degrees based on the mouse position
  a = (@x / width) * 90
  # Convert it to radians
  @theta = a.radians
  # Start the tree from the bottom of the screen
  translate(width / 2, height)
  # Draw a line 60 pixels
  h = height / 3
  line(0, 0, 0,  -h)
  # Move to the end of that line
  translate(0,-h)
  # Start the recursive branching!
  branch(h)
  
  @x += @dx
  if @x < 0
    puts "Time after this iteration: " + (Time.now - @start_time).to_s
  end
  if @x > width || @x < 0
    @dx = - @dx
    @x += @dx * 2
  end
end

def branch(h)
  # Each branch will be 2/3rds the size of the previous one
  h *= 0.66  
  # All recursive functions must have an exit condition!!!!
  # Here, ours is when the length of the branch is 2 pixels or less
  if h > 2
    push_matrix       # Save the current state of transformation (i.e. where are we now)
    rotate(@theta)   # Rotate by theta
    line(0, 0, 0, -h)   # Draw the branch
    translate(0, -h)  # Move to the end of the branch
    branch(h)        # Ok, now call myself to draw two new branches!!
    pop_matrix        # Whenever we get back here, we "pop" in order to restore the previous matrix state
    
    # Repeat the same thing, only branch off to the "left" this time!
    push_matrix
    rotate(- @theta)
    line(0, 0, 0, -h)
    translate(0, -h)
    branch(h)
    pop_matrix
  end
end

Version data entries

5 entries across 5 versions & 1 rubygems

Version	Path
ruby-processing-2.6.3	samples/contributed/tree.rb
ruby-processing-2.6.2	samples/contributed/tree.rb
ruby-processing-2.6.1	samples/contributed/tree.rb
ruby-processing-2.6.0	samples/contributed/tree.rb
ruby-processing-2.5.1	samples/contributed/tree.rb