Create simulation.js

simulation.js

@@ -0,0 +1,121 @@
+let particles = [];
+const numParticles = 25;
+let cylinderRadius = 200;
+let cylinderHeight = 400;
+let sphereRadius = 300;
+let rotationAngle = 0;
+let zoom = 1;
+let zoomDirection = 1;
+
+function setup() {
+  createCanvas(800, 800, WEBGL);
+  colorMode(HSB, 360, 100, 100);
+  
+  for (let i = 0; i < numParticles; i++) {
+    particles.push(new Particle(
+      random(-cylinderRadius, cylinderRadius),
+      random(-cylinderHeight/2, cylinderHeight/2),
+      random(-cylinderRadius, cylinderRadius),
+      i * (360/numParticles)
+    ));
+  }
+}
+
+function draw() {
+  background(0);
+  scale(zoom);
+  
+  zoom += 0.002 * zoomDirection;
+  if (zoom > 1.5) zoomDirection = -1;
+  if (zoom < 0.8) zoomDirection = 1;
+  
+  rotateY(rotationAngle);
+  rotationAngle += 0.005;
+  
+  push();
+  noFill();
+  stroke(200, 50, 50, 50);
+  sphere(sphereRadius);
+  pop();
+  
+  push();
+  noFill();
+  stroke(100, 50, 50, 50);
+  cylinder(cylinderRadius, cylinderHeight);
+  pop();
+  
+  for (let particle of particles) {
+    particle.update();
+    particle.checkCollisions();
+    particle.display();
+  }
+}
+
+class Particle {
+  constructor(x, y, z, hue) {
+    this.pos = createVector(x, y, z);
+    this.vel = p5.Vector.random3D().mult(random(2, 5));
+    this.radius = 8;
+    this.hue = hue;
+    this.trail = [];
+    this.maxTrailLength = 20;
+  }
+  
+  update() {
+    this.pos.add(this.vel);
+    this.trail.push(this.pos.copy());
+    if (this.trail.length > this.maxTrailLength) {
+      this.trail.splice(0, 1);
+    }
+  }
+  
+  checkCollisions() {
+    let radialDist = sqrt(this.pos.x * this.pos.x + this.pos.z * this.pos.z);
+    if (radialDist + this.radius > cylinderRadius) {
+      let normal = createVector(this.pos.x, 0, this.pos.z).normalize();
+      let dotProduct = this.vel.dot(normal);
+      this.vel.sub(normal.mult(2 * dotProduct));
+      this.pos.set(
+        this.pos.x * (cylinderRadius - this.radius) / radialDist,
+        this.pos.y,
+        this.pos.z * (cylinderRadius - this.radius) / radialDist
+      );
+    }
+    
+    if (this.pos.y + this.radius > cylinderHeight/2) {
+      this.vel.y = -abs(this.vel.y);
+      this.pos.y = cylinderHeight/2 - this.radius;
+    }
+    if (this.pos.y - this.radius < -cylinderHeight/2) {
+      this.vel.y = abs(this.vel.y);
+      this.pos.y = -cylinderHeight/2 + this.radius;
+    }
+    
+    let distFromCenter = this.pos.mag();
+    if (distFromCenter + this.radius > sphereRadius) {
+      let normal = this.pos.copy().normalize();
+      let dotProduct = this.vel.dot(normal);
+      this.vel.sub(normal.mult(2 * dotProduct));
+      this.pos.setMag(sphereRadius - this.radius);
+    }
+  }
+  
+  display() {
+    push();
+    noFill();
+    strokeWeight(2);
+    beginShape();
+    for (let i = 0; i < this.trail.length; i++) {
+      let alpha = map(i, 0, this.trail.length, 0, 100);
+      stroke(this.hue, 80, 100, alpha);
+      vertex(this.trail[i].x, this.trail[i].y, this.trail[i].z);
+    }
+    endShape();
+    
+    fill(this.hue, 80, 100);
+    noStroke();
+    translate(this.pos.x, this.pos.y, this.pos.z);
+    sphere(this.radius);
+    pop();
+  }
+}