projector/gravballs.html at master · blueyred/projector · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Swirling Balls</title>
<style>
body {
  margin: 0;
  overflow: hidden;
}
canvas {
  display: block;
}
#keys{
    position: absolute;
    bottom: 0;
    right:0;
    padding: 5px 20px;
    background-color: white;
    color: black;
    font-family: "Courier New", Courier, monospace;
    font-size: 14px;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<div id="keys" style="display:none">
  <p><b>F</b> fullscreen</p>

  <p><b>Q</b> <b>W</b> Size</p>
  <p><b>Z</b> <b>X</b> Num balls</p>

</div>
<script>
const keysEl = document.getElementById('keys');
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

canvas.width = window.innerWidth;
canvas.height = window.innerHeight;

var numBalls = 100; // Initial number of balls
var maxRadius = 50; // Maximum radius of a ball

var balls = [];

// Physics parameters
var G = 0.001; // Gravitational constant
var minDist = maxRadius * 4; // Minimum distance for repulsion
var minDistSquared = minDist * minDist; // Square of the minimum distance
var maxDist = maxRadius * 8; // Maximum distance for attraction
var maxDistSquared = maxDist * maxDist; // Square of the maximum distance
var maxVelocity = 5; // Maximum allowed velocity
var maxVelocitySquared = maxVelocity * maxVelocity; // Square of the maximum velocity
var edgeRepulsionFactor = 0.5; // Strength of the edge repulsion
var lineWidth = 2;


const white = 'hsl(0,0%,100%)';
const black = 'hsl(0,0%,0%)';

var foreColor = white;
var backColor = black;

function Ball(x, y, radius, dx, dy) {
  this.x = x;
  this.y = y;
  this.radius = radius;
  this.linewidth = maxRadius * 0.1;//radius * 0.16667;
  this.dx = dx;
  this.dy = dy;
  this.mass = Math.PI * radius * radius; // Mass proportional to area
  //this.color = `hsl(${Math.random() * 360}, 100%, 50%)`; // Random color
  this.color = foreColor;

  this.circledraw = function() {
    ctx.beginPath();
    ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false);
    ctx.fillStyle = this.color;
    ctx.fill();
    ctx.closePath();
  };

  this.draw = function() {
    ctx.strokeStyle = this.color;
    ctx.lineWidth = this.linewidth;

    // Draw three concentric circles
    for (let i = 1; i <= 3; i++) {
      let r = this.radius * (i / 3); // Radius of the current circle
      ctx.beginPath();
      ctx.arc(this.x, this.y, r, 0, Math.PI * 2, false);
      ctx.stroke();
      ctx.closePath();
    }
  };

  this.update = function() {
    // Calculate gravitational forces from other balls
    for (let i = 0; i < balls.length; i++) {
      if (balls[i] === this) continue; // Skip self-interaction

      let dx = balls[i].x - this.x;
      let dy = balls[i].y - this.y;
      let distanceSquared = dx * dx + dy * dy;

      if (distanceSquared < maxDistSquared && distanceSquared > minDistSquared) {
        // Attraction (inverse square law)
        let distance = Math.sqrt(distanceSquared);
        let force = G * this.mass * balls[i].mass / distanceSquared;
        let angle = Math.atan2(dy, dx);
        this.dx += force * Math.cos(angle) / this.mass;
        this.dy += force * Math.sin(angle) / this.mass;
      } else if (distanceSquared < minDistSquared) {
        // Repulsion (inverse square law)
        let distance = Math.sqrt(distanceSquared);
        let force = -G * this.mass * balls[i].mass / distanceSquared;
        let angle = Math.atan2(dy, dx);
        this.dx += force * Math.cos(angle) / this.mass;
        this.dy += force * Math.sin(angle) / this.mass;
      }
    }

    // Limit velocity
    let velocitySquared = this.dx * this.dx + this.dy * this.dy;
    if (velocitySquared > maxVelocitySquared) {
      let scale = maxVelocity / Math.sqrt(velocitySquared);
      this.dx *= scale;
      this.dy *= scale;
    }

    // Edge repulsion
    let edgeDistanceX = 2 * this.radius;
    let edgeDistanceY = 2 * this.radius;

    if (this.x < edgeDistanceX) {
      this.dx += edgeRepulsionFactor * (edgeDistanceX - this.x) / edgeDistanceX;
    } else if (this.x > canvas.width - edgeDistanceX) {
      this.dx -= edgeRepulsionFactor * (this.x - (canvas.width - edgeDistanceX)) / edgeDistanceX;
    }

    if (this.y < edgeDistanceY) {
      this.dy += edgeRepulsionFactor * (edgeDistanceY - this.y) / edgeDistanceY;
    } else if (this.y > canvas.height - edgeDistanceY) {
      this.dy -= edgeRepulsionFactor * (this.y - (canvas.height - edgeDistanceY)) / edgeDistanceY;
    }

    // Update position based on velocity
    this.x += this.dx;
    this.y += this.dy;

    this.draw();
  };
}

function generateBalls() {
  balls = []; // Clear existing balls
  for (let i = 0; i < numBalls; i++) {
    let radius = Math.random() * maxRadius + (maxRadius * 0.5); // Radius between 10 and maxRadius
    let x = Math.random() * (canvas.width - radius * 2) + radius;
    let y = Math.random() * (canvas.height - radius * 2) + radius;
    let dx = (Math.random() - 0.5) * 2; // Small initial random velocity
    let dy = (Math.random() - 0.5) * 2;
    balls.push(new Ball(x, y, radius, dx, dy));
  }
}

function animate() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  ctx.fillStyle = backColor;
  ctx.fillRect(0, 0, canvas.width, canvas.height);


  for (let i = 0; i < balls.length; i++) {
    balls[i].update();
  }

  requestAnimationFrame(animate);
}

// Event Listeners
window.addEventListener('resize', () => {
  canvas.width = window.innerWidth;
  canvas.height = window.innerHeight;
  generateBalls(); // Regenerate balls on resize
});

document.addEventListener('keydown', (e) => {
  if (e.key === 'z') {
    lessBalls();
  }
  if (e.key === 'x') {
    moreBalls();
  }
  if (e.key === 'q') {
    smaller();
  }
  if (e.key === 'w') {
    bigger();
  }
  if (e.key === "k") {
      toggleKeys();
  }
  if (e.key === "f") {
      toggleFullScreen();
  }
});

function toggleKeys(){
    keysEl.style.display = keysEl.style.display === "none" ? "block" : "none";
}

// Control Functions
function lessBalls() {
  changeNumBalls(-1);
}

function moreBalls() {
  changeNumBalls(1);
}

function changeNumBalls(change) {
  numBalls += change;
  if (numBalls < 1) {
    numBalls = 1;
  }
  generateBalls();
}

function smaller() {
  changeMaxSize(-5);
}

function bigger() {
  changeMaxSize(5);
}

function changeMaxSize(change) {
    maxRadius += change;
  if (maxRadius < 10) {
    maxRadius = 10;
  }
  generateBalls();
}

function toggleFullScreen() {
  if (!document.fullscreenElement) {
    document.documentElement.requestFullscreen();
  } else if (document.exitFullscreen) {
    document.exitFullscreen();
  }
}

// Initialize
generateBalls();
animate();
</script>
</body>
</html>