Contents

require 'ruby-processing'

# Additive Wave
# by Daniel Shiffman. 
# 
# Create a more complex wave by adding two waves together. 

class AdditiveWave < Processing::App

  def setup
  	@max_waves = 4				    # Total number of waves to add together
    @wave_width = width + 16	# Width of entire wave
    @x_spacing = 8				    # How far apart should each horizontal location be spaced
    @theta = 0.0
    @amplitude = []				    # Height of wave
    @dx = []					        # Value for incrementing X, to be calculated as a function of period and x_spacing
    
    @max_waves.times do |i|
    	@amplitude << random( 10, 30 )
    	period = random( 100, 300 ) # How many pixels before the wave repeats
    	@dx << (TWO_PI / period) * @x_spacing
    end
    
    frame_rate 30
    color_mode RGB, 255, 255, 255, 100
    smooth
  end
  
  def draw
  	background 0
  	calculate_wave
  	render_wave
  end
  
  def calculate_wave
  	# Increment theta (try different values for 'angular velocity' here
  	@theta += 0.02
  	
  	# Set all height values to zero
  	@y_values = Array.new @wave_width/@x_spacing, 0
  	
  	# Accumulate wave height values
  	@max_waves.times do |j|
  		x = @theta
  		@y_values.length.times do |i|
  			# Every other wave is cosine instead of sine
  			value = (j % 2) == 0 ? sin(x) : cos(x)
  			@y_values[i] += value * @amplitude[j]
  			x += @dx[j]
  		end
  	end
  end
  
  def render_wave
  	# A simple way to draw the wave with an ellipse at each location
  	no_stroke
  	fill 255, 50
  	ellipse_mode CENTER
  	@y_values.each_with_index do |y, i|
  		ellipse i*@x_spacing, width/2+y, 16, 16
  	end
  end
  
end

AdditiveWave.new :title => "Additive Wave", :width => 200, :height => 200

Version data entries

9 entries across 9 versions & 1 rubygems

Version	Path
ruby-processing-1.0.11	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.10.1	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.9	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.4	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.3	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.5	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.6	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.7	samples/processing_app/basics/math/additive_wave.rb
ruby-processing-1.0.8	samples/processing_app/basics/math/additive_wave.rb