The Sound of Flocking

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I added some simple sound generation code to Daniel Shiffman’s Flocking code. I use two pulse oscillators. One for the x-axis and one for the y-axis.

The average position of the boids is mapped to the frequency of each respective oscillator. So, if the boids move, in general, up, the pitch of one oscillator goes up. Similarly, if the boids move to the right, the second oscillator increases in pitch. Finally, the standard deviations of the locations of the boids are mapped to the width of the oscillators. I’m glossing over some details, but that’s the basic idea.

Here is the crux of my sound mapping code:

    x_avg = self.get_x_avg()
    x_velocity_avg = self.get_x_velocity_avg()
    y_velocity_avg = self.get_y_velocity_avg()
    pos = (x_avg / w) * 2 - 1
    y_avg = self.get_y_avg()
    
    x_std_dev = std_dev([b.location[0] for b in self.boids])
    y_std_dev = std_dev([b.location[1] for b in self.boids])
    
    # Syntax: .set(  freq,               width, amp,            add, pos)
    ch_1.set(       x_avg, x_std_dev / (w / 2),   1, x_velocity_avg, pos)
    ch_2.set(-(h - y_avg), y_std_dev / (h / 2),   1, y_velocity_avg, pos)

The full code is here. I would recommend running the code as the video is only a random three minute sample of the idea.

Of course the screen wraps around. (The boids are flying on the surface of a torus.) The way I’ve written it, the audio also “wraps around”. It might make sense to use absolute frequencies instead, and have the app stop after the pitch goes out of hearing range. Maybe I will try that.

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