cannon/test/Body.js

A lightweight 3D physics engine written in JavaScript.

var Vec3 =     require("../src/math/Vec3");
var Mat3 =     require("../src/math/Mat3");
var Quaternion = require("../src/math/Quaternion");
var Box =      require('../src/shapes/Box');
var Sphere =      require('../src/shapes/Sphere');
var Body =      require('../src/objects/Body');

module.exports = {
    computeAABB : function(test){
        var body = new Body({ mass: 1 });
        body.addShape(new Box(new Vec3(1,1,1)));
        body.computeAABB();
        test.equal(body.aabb.lowerBound.x,-1);
        test.equal(body.aabb.lowerBound.y,-1);
        test.equal(body.aabb.lowerBound.z,-1);
        test.equal(body.aabb.upperBound.x,1);
        test.equal(body.aabb.upperBound.y,1);
        test.equal(body.aabb.upperBound.z,1);

        body.position.x = 1;
        body.computeAABB();

        test.equal(body.aabb.lowerBound.x,0);
        test.equal(body.aabb.upperBound.x,2);

        test.done();
    },

    updateInertiaWorld : function(test){
        var body = new Body({ mass: 1 });
        body.addShape(new Box(new Vec3(1,1,1)));
        body.quaternion.setFromEuler(Math.PI/2,0,0);
        body.updateInertiaWorld();
        test.done();
    },

    pointToLocalFrame : function(test){
        var body = new Body({ mass: 1 });
        body.addShape(new Sphere(1));
        body.position.set(1,2,2);
        var localPoint = body.pointToLocalFrame(new Vec3(1,2,3));
        test.ok(localPoint.almostEquals(new Vec3(0,0,1)));
        test.done();
    },

    pointToWorldFrame : function(test){
        var body = new Body({ mass: 1 });
        body.addShape(new Sphere(1));
        body.position.set(1,2,2);
        var worldPoint = body.pointToWorldFrame(new Vec3(1,0,0));
        test.ok(worldPoint.almostEquals(new Vec3(2,2,2)));
        test.done();
    },

    addShape : function(test){
        var sphereShape = new Sphere(1);

        var bodyA = new Body({
            mass: 1,
            shape: sphereShape
        });
        var bodyB = new Body({
            mass: 1
        });
        bodyB.addShape(sphereShape);

        test.deepEqual(bodyA.shapes, bodyB.shapes, 'Adding shape via options did not work.');
        test.deepEqual(bodyA.inertia, bodyB.inertia);

        test.done();
    },

    applyForce : function(test){
        var sphereShape = new Sphere(1);
        var body = new Body({
            mass: 1,
            shape: sphereShape
        });

        var worldPoint = new Vec3(1,0,0);
        var forceVector = new Vec3(0,1,0);
        body.applyForce(forceVector, worldPoint);
        test.deepEqual(body.force, forceVector);
        test.deepEqual(body.torque, new Vec3(0,0,1));

        test.done();
    },

    applyLocalForce : function(test){
        var sphereShape = new Sphere(1);
        var body = new Body({
            mass: 1,
            shape: sphereShape
        });
        body.quaternion.setFromAxisAngle(new Vec3(1, 0, 0), Math.PI / 2);

        var localPoint = new Vec3(1,0,0);
        var localForceVector = new Vec3(0,1,0);
        body.applyLocalForce(localForceVector, localPoint);
        test.ok(body.force.almostEquals(new Vec3(0,0,1))); // The force is rotated to world space

        test.done();
    },

    applyImpulse : function(test){
        var sphereShape = new Sphere(1);
        var body = new Body({
            mass: 1,
            shape: sphereShape
        });

        var f = 1000;
        var dt = 1 / 60;
        var worldPoint = new Vec3(0,0,0);
        var impulse = new Vec3(f*dt,0,0);
        body.applyImpulse(impulse, worldPoint);

        test.ok(body.velocity.almostEquals(new Vec3(f*dt,0,0)));

        test.done();
    },

    applyLocalImpulse : function(test){
        var sphereShape = new Sphere(1);
        var body = new Body({
            mass: 1,
            shape: sphereShape
        });
        body.quaternion.setFromAxisAngle(new Vec3(1, 0, 0), Math.PI / 2);

        var f = 1000;
        var dt = 1 / 60;
        var localPoint = new Vec3(1,0,0);
        var localImpulseVector = new Vec3(0,f*dt,0);
        body.applyLocalImpulse(localImpulseVector, localPoint);
        test.ok(body.velocity.almostEquals(new Vec3(0,0,f*dt))); // The force is rotated to world space

        test.done();
    },
};