Code Production: The Physics of the Chase

Concept & Inspiration

For this assignment, I was tasked with finding an example of movement in nature and simulating it using code. I started by looking at how birds move in flocks. There is a specific fluidity to how they accelerate and glide that feels very different from mechanical movement.

I found this video of birds in flight which served as my primary visual reference:

https://www.youtube.com/watch?v=SCX946jtKXw

The Pivot

While watching the video, I realized that we almost always observe birds from the ground looking up. I wondered: How do birds see each other?

I decided to shift the perspective. Instead of a human watching a bird, I wanted to create a First-Person Flyer (FPF) experience. The concept became a “Bird Chase Simulation,” where the user plays as a predator bird (or perhaps a playful friend bird) trying to catch up to a leading bird.

My goal was to give the movement “personality” not just through the way the bird looks, but through how the acceleration feels. High acceleration shouldn’t just mean “go faster”, it should feel energetic and slightly chaotic, changing the bird’s perspective of the world.

Process

Before I could make it look like a bird, I had to make it move like one. The prompt required controlling motion only by manipulating acceleration.

I started with a greyboxing phase. I created a relationship where the distance between the player and the target wasn’t represented by X/Y coordinates, but by the scale of the target. If you accelerate and get closer, the target gets bigger,if you stop flapping (drag), you fall back, and the target shrinks.

Here is a screen recording of that initial physics test:

The Code

The part of the code I am most proud of is the relationship between the Acceleration Input and the Camera Shake.

The prompt asked us to give the movement personality. I achieved this by making the “camera” (the viewport) physically shake when the user pushes the acceleration slider to the max. It simulates the physical exertion of flapping wings hard against the wind. It bridges the gap between the math (acceleration numbers) and the feeling (struggle/speed).

Here is the snippet that handles that logic:

// === PHYSICS SECTION ===
  let accVector = createVector(0, accInput);
  playerVel.add(accVector); 
  
  // === CAMERA SHAKE EFFECT ===
  // Add shake when accelerating hard (makes it feel more dynamic)
  let shakeX = 0;
  let shakeY = 0;
  
  // Only shake if we are putting in significant effort (> 0.05)
  if (accInput > 0.05) {
    // Map the shake intensity to the acceleration input
    let shakeAmt = map(accInput, 0, 0.5, 0.5, 6); 
    shakeX = random(-shakeAmt, shakeAmt);
    shakeY = random(-shakeAmt, shakeAmt);
  }

  // Later, in the drawing section:
  translate(width/2 + shakeX, height/2 + shakeY);

The Simulation

To finalize the piece, I added a circular clipping mask to create a “binocular” or “focus” effect, simulating the bird’s vision. I also added wind lines that react to the player’s speed to create a parallax effect, enhancing the sensation of forward momentum.

Instructions:

Use the slider at the bottom to control your Acceleration (how hard you are flapping).
Try to catch up to the bird in front of you.
Notice how the view shakes and the wind rushes faster as you exert more energy.

Reflection & Future Work

This project was a great exercise in using simple variables (acceleration and scale) to create a 3D illusion. The hardest part was tuning the “drag” or air resistance. If the drag was too high, it felt like flying through soup; too low, and the bird felt like a rocket with no weight.

I’m happy with how the beak breathing animation and the camera shake added life to the static shapes.

For the future: Currently, the movement is linear (forward/backward). I would love to introduce steering, allowing the player to move left and right to chase the target bird as it weaves through the sky. I also think adding a Stamina bar would add a game-like element, forcing the player to choose when to glide and when to sprint.

Assignment 2 : Yash