Add completed catapult

CM2030 Graphics Programming/Topic 4/4.3.5/sketch.js

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+// Example is based on examples from:
+// http://brm.io/matter-js/
+// https://github.com/shiffman/p5-matter
+// https://github.com/b-g/p5-matter-examples
+
+// module aliases
+let Engine = Matter.Engine;
+let Render = Matter.Render;
+let World = Matter.World;
+let Bodies = Matter.Bodies;
+let Constraint = Matter.Constraint;
+
+let engine;
+let ground;
+
+let ball1;
+let ball2;
+
+let catapult;
+let catapultSpacer;
+let constraint;
+
+function setup() {
+  createCanvas(800, 600);
+  engine = Engine.create(); // create an engine
+  setupCatapult();
+  setupBalls();
+  setupGround();
+}
+/////////////////////////////////////////////////////////////
+function draw() {
+  background(0);
+  Engine.update(engine);
+  drawBalls();
+  drawCatapult();
+  drawGround();
+}
+
+function mouseClicked() {
+  if(ball2 == null)
+  {
+    ball2 = Bodies.circle(mouseX, mouseY, 50, {density: 0.01});
+    World.add(engine.world, [ball2]);
+  }
+}
+
+/////////////////////////////////////////////////////////////
+function setupCatapult(){
+  catapult = Bodies.rectangle(width/2, height - 85, width * 0.75, 10);
+  constraint = Constraint.create({
+    bodyB: catapult,
+    pointA: {x: width/2, y: height - 85},
+    stiffness: 1
+  });
+  catapultSpacer = Bodies.rectangle(150, height - 50, 10, 60, {isStatic: true});
+  World.add(engine.world, [catapult, constraint, catapultSpacer]);
+}
+/////////////////////////////////////////////////////////////
+function drawCatapult(){
+  fill(255);
+  drawVertices(catapult.vertices);
+  fill(255, 0, 0);
+  drawVertices(catapultSpacer.vertices);
+}
+/////////////////////////////////////////////////////////////
+function setupBalls(){
+  let radius1 = 15;
+  ball1 = Bodies.circle(150, height - 50 - 55, radius1);
+  World.add(engine.world, [ball1]);
+}
+/////////////////////////////////////////////////////////////
+function drawBalls(){
+  fill(0, 255, 0);
+  drawVertices(ball1.vertices);
+  if(ball2 != null)
+    drawVertices(ball2.vertices);
+}
+/////////////////////////////////////////////////////////////
+function setupGround(){
+  ground = Bodies.rectangle(400, height-10, 810, 25, {isStatic: true});
+  World.add(engine.world, [ground]);
+}
+/////////////////////////////////////////////////////////////
+function drawGround(){
+  noStroke();
+  fill(128);
+  drawVertices(ground.vertices);
+}
+////////////////////////////////////////////////////////////////
+// ******* HELPER FUNCTIONS *********
+// DO NOT WRITE BELOW HERE
+/////////////////////////////////////////////////////////////
+function drawVertices(vertices) {
+  beginShape();
+  for (let i = 0; i < vertices.length; i++) {
+    vertex(vertices[i].x, vertices[i].y);
+  }
+  endShape(CLOSE);
+}
+
+function drawConstraint(constraint) {
+  var offsetA = constraint.pointA;
+  var posA = {x:0, y:0};
+  if (constraint.bodyA) {
+    posA = constraint.bodyA.position;
+  }
+  var offsetB = constraint.pointB;
+  var posB = {x:0, y:0};
+  if (constraint.bodyB) {
+    posB = constraint.bodyB.position;
+  }
+  line(
+    posA.x + offsetA.x,
+    posA.y + offsetA.y,
+    posB.x + offsetB.x,
+    posB.y + offsetB.y
+  );
+}