Angle constraints (#837, rebased)

demo/index.html

@@ -57,4 +57,4 @@
     <script src="./js/matter-demo.poly-decomp.c3d015.min.js"></script>
     <script src="./js/matter-demo.a280d3.min.js"></script>
   </body>
-</html>
+</html>

examples/angleConstraints.js

@@ -0,0 +1,223 @@
+var Example = Example || {};
+
+Example.angleConstraints = function() {
+    var Engine = Matter.Engine,
+        Render = Matter.Render,
+        Runner = Matter.Runner,
+        Constraint = Matter.Constraint,
+        MouseConstraint = Matter.MouseConstraint,
+        Mouse = Matter.Mouse,
+        World = Matter.World,
+        Bodies = Matter.Bodies;
+
+    // create engine
+    var engine = Engine.create(),
+        world = engine.world;
+
+    // create renderer
+    var render = Render.create({
+        element: document.body,
+        engine: engine,
+        options: {
+            width: 800,
+            height: 600,
+            showAngleIndicator: true
+        }
+    });
+
+    Render.run(render);
+
+    // create runner
+    var runner = Runner.create();
+    Runner.run(runner, engine);
+
+    // add stiff global constraint
+    var body = Bodies.polygon(150, 200, 5, 30);
+
+    var constraint = Constraint.create({
+        pointA: { x: 150, y: 100 },
+        bodyB: body,
+        pointB: { x: 0, y: -10 },
+
+        angleAStiffness: 1
+    });
+
+    World.add(world, [body, constraint]);
+
+    // add soft global constraint
+    var body = Bodies.polygon(280, 200, 3, 30);
+
+    var constraint = Constraint.create({
+        pointA: { x: 280, y: 120 },
+        bodyB: body,
+        pointB: { x: 0, y: -7 },
+        stiffness: 0.001,
+
+        angleA: 0,
+        angleAStiffness: 0.01
+    });
+
+    World.add(world, [body, constraint]);
+
+    // add damped soft global constraint
+    var body = Bodies.polygon(400, 100, 4, 30);
+
+    var constraint = Constraint.create({
+        bodyA: body,
+        pointA: { x: -10, y: -10 },
+        pointB: { x: 400, y: 120 },
+        stiffness: 0.001,
+        damping: 0.05,
+
+        angleBStiffness: 1,
+        angleB: 0,
+        angleBMin: -1,
+        angleBMax: 1
+    });
+
+    World.add(world, [body, constraint]);
+
+    // add revolute constraint
+    var body = Bodies.rectangle(600, 200, 200, 20);
+    var ball = Bodies.circle(550, 150, 20);
+
+    var constraintR = Constraint.create({
+        bodyA: body,
+        pointB: { x: 600, y: 200 },
+        length: 0,
+
+        angleAStiffness: 1,
+        angleAMin: -0.5,
+        angleAMax: 0.5
+    });
+
+    World.add(world, [body, ball, constraintR]);
+
+    // add revolute multi-body constraint
+    var body = Bodies.rectangle(400, 400, 100, 20);
+    var ball = Bodies.circle(500, 400, 20);
+
+    var constraint = Constraint.create({
+        bodyA: body,
+        bodyB: ball,
+
+        angleAStiffness: 0.9,
+        angleBMin: -0.5,
+        angleBMax: 0.5,
+        angleBStiffness: 1
+    });
+
+    World.add(world, [body, ball, constraint]);
+
+    // add stiff multi-body constraint
+    var bodyA = Bodies.polygon(100, 400, 6, 20);
+    var bodyB = Bodies.polygon(200, 400, 1, 50, { angle: -0.05 });
+
+    var constraint = Constraint.create({
+        bodyA: bodyA,
+        pointA: { x: -10, y: -10 },
+        bodyB: bodyB,
+        pointB: { x: -10, y: -10 },
+
+        angleAStiffness: 1,
+        angleBMin: -0.5 - Math.PI,
+        angleBMax: 0.5 - Math.PI,
+        angleBStiffness: 1
+    });
+
+    World.add(world, [bodyA, bodyB, constraint]);
+
+    // add soft global constraint
+    var bodyA = Bodies.polygon(300, 400, 4, 20);
+    var bodyB = Bodies.polygon(400, 400, 3, 30);
+
+    var constraint = Constraint.create({
+        bodyA: bodyA,
+        pointA: { x: -10, y: -10 },
+        bodyB: bodyB,
+        pointB: { x: -10, y: -7 },
+        stiffness: 0.01,
+
+        angleAMin: Math.PI * 0.1,
+        angleAMax: Math.PI * 0.5,
+        angleAStiffness: 0.1,
+        angleBMin: -0.5 - Math.PI,
+        angleBMax: 0.5 - Math.PI,
+        angleBStiffness: 0.1
+    });
+
+    World.add(world, [bodyA, bodyB, constraint]);
+
+    // add damped soft global constraint
+    var bodyA = Bodies.polygon(500, 400, 6, 30);
+    var bodyB = Bodies.polygon(600, 400, 7, 60);
+
+    var constraint = Constraint.create({
+        bodyA: bodyA,
+        pointA: { x: -10, y: -10 },
+        bodyB: bodyB,
+        pointB: { x: -10, y: -10 },
+        stiffness: 0.001,
+        damping: 0.1,
+
+        angleAMin: Math.PI * 0.1,
+        angleAMax: Math.PI * 0.5,
+        angleAStiffness: 1,
+        angleBMin: -0.5 - Math.PI,
+        angleBMax: 0.5 - Math.PI,
+        angleBStiffness: 0.01
+    });
+
+    World.add(world, [bodyA, bodyB, constraint]);
+
+    World.add(world, [
+        // walls
+        Bodies.rectangle(400, 0, 800, 50, { isStatic: true }),
+        Bodies.rectangle(400, 600, 800, 50, { isStatic: true }),
+        Bodies.rectangle(800, 300, 50, 600, { isStatic: true }),
+        Bodies.rectangle(0, 300, 50, 600, { isStatic: true })
+    ]);
+
+    // add mouse control
+    var mouse = Mouse.create(render.canvas),
+        mouseConstraint = MouseConstraint.create(engine, {
+            mouse: mouse,
+            constraint: {
+                // allow bodies on mouse to rotate
+                angularStiffness: 0,
+                render: {
+                    visible: false
+                }
+            }
+        });
+
+    World.add(world, mouseConstraint);
+
+    // keep the mouse in sync with rendering
+    render.mouse = mouse;
+
+    // fit the render viewport to the scene
+    Render.lookAt(render, {
+        min: { x: 0, y: 0 },
+        max: { x: 800, y: 600 }
+    });
+
+    // context for MatterTools.Demo
+    return {
+        engine: engine,
+        runner: runner,
+        render: render,
+        canvas: render.canvas,
+        stop: function() {
+            Matter.Render.stop(render);
+            Matter.Runner.stop(runner);
+        }
+    };
+};
+
+Example.angleConstraints.title = 'Angle Constraints';
+Example.angleConstraints.for = '>0.15.0';
+
+if (typeof module !== 'undefined') {
+    module.exports = Example.angleConstraints;
+}

examples/index.js

@@ -1,5 +1,6 @@
 module.exports = {
     airFriction: require('./airFriction.js'),
+    angleConstraints: require('./angleConstraints.js'),
     avalanche: require('./avalanche.js'),
     ballPool: require('./ballPool.js'),
     bridge: require('./bridge.js'),