cannon/test/Ray.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 Trimesh = require('../src/shapes/Trimesh');
var Plane = require('../src/shapes/Plane');
var Ray = require('../src/collision/Ray');
var Body = require('../src/objects/Body');
var RaycastResult = require('../src/collision/RaycastResult');
var Heightfield = require('../src/shapes/Heightfield');

module.exports = {

    construct : function(test) {
        test.expect(0);
        var r = new Ray(new Vec3(), new Vec3(1,0,0));
        test.done();
    },

    intersectBody : function(test) {
        var r = new Ray(new Vec3(5,0,0), new Vec3(-5, 0, 0));
        r.skipBackfaces = true;
        var shape = createPolyhedron(0.5);
        var body = new Body({ mass: 1 });
        body.addShape(shape);

        var result = new RaycastResult();

        r.intersectBody(body, result);
        test.ok(result.hasHit);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5, 0, 0)));

        // test rotating the body first
        result.reset();
        body.quaternion.setFromAxisAngle(new Vec3(1,0,0), Math.PI);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));

        // test shooting from other direction
        result.reset();
        r.to.set(0,0,-5);
        r.from.set(0,0,5);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0,0,0.5)));

        // test miss
        result.reset();
        var r = new Ray(new Vec3(5, 1, 0), new Vec3(-5, 1, 0));
        r.intersectBody(body, result);
        test.equals(result.hasHit, false);

        test.done();
    },

    intersectBodies : function(test) {
        var r = new Ray(new Vec3(5,0,0), new Vec3(-5,0,0));
        r.skipBackfaces = true;
        var shape = createPolyhedron(0.5);
        var body1 = new Body({ mass: 1 });
        body1.addShape(shape);
        var body2 = new Body({ mass: 1 });
        body2.addShape(shape);
        body2.position.x = -2;

        var result = new RaycastResult();
        r.intersectBodies([body1, body2], result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));
        test.done();
    },

    box: function(test){
        var r = new Ray(new Vec3(5,0,0),new Vec3(-5, 0, 0));
        r.skipBackfaces = true;
        var shape = new Box(new Vec3(0.5,0.5,0.5));
        var body = new Body({ mass: 1 });
        body.addShape(shape);
        var result = new RaycastResult();

        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));

        result.reset();
        body.quaternion.setFromAxisAngle(new Vec3(1,0,0), Math.PI / 2);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));

        result.reset();
        body.quaternion.setFromAxisAngle(new Vec3(1,0,0), Math.PI);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));

        result.reset();
        body.quaternion.setFromAxisAngle(new Vec3(1,0,0), 3 * Math.PI / 2);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0.5,0,0)));

        test.done();
    },

    sphere: function(test){
        var r = new Ray(new Vec3(5,0,0), new Vec3(-5, 0, 0));
        r.skipBackfaces = true;
        var shape = new Sphere(1);
        var body = new Body({ mass: 1 });
        body.addShape(shape);

        var result = new RaycastResult();
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(1,0,0)));

        result.reset();
        body.position.set(1, 0, 0);
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(2,0,0)));

        result.reset();
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(2,0,0)));

        result.reset();
        var shape2 = new Sphere(1);
        var body2 = new Body({ mass: 1 });
        body2.addShape(shape2, new Vec3(1, 0, 0));
        r.intersectBody(body2, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(2,0,0)));

        test.done();
    },

    heightfield: function(test){
        var r = new Ray(new Vec3(0, 0, 10), new Vec3(0, 0, -10));
        r.skipBackfaces = true;
        var data = [
            [1, 1, 1],
            [1, 1, 1],
            [1, 1, 1]
        ];
        var shape = new Heightfield(data, {
            elementSize: 1
        });
        var body = new Body({ mass: 1 }, new Vec3(-1.5, -1.5, 0));
        body.addShape(shape);

        // Hit
        var result = new RaycastResult();
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.deepEqual(result.hitPointWorld, new Vec3(0, 0, 1));

        // Miss
        var result = new RaycastResult();
        r.from.set(-100, -100, 10);
        r.to.set(-100, -100, -10);
        r.intersectBody(body, result);
        test.equals(result.hasHit, false);

        // Hit all triangles!
        var result = new RaycastResult();
        for(var i = 0; i < data.length - 1; i++){ // 3x3 data points will have 2x2 rectangles in the field
            for(var j = 0; j < data[i].length - 1; j++){
                for(var k = 0; k < 2; k++){
                    result.reset();
                    r.from.set(i + 0.25, j + 0.25, 10);
                    r.to.set(i + 0.25, j + 0.25, -10);
                    if (k) {
                        r.from.x += 0.5;
                        r.from.y += 0.5;
                        r.to.x += 0.5;
                        r.to.y += 0.5;
                    }
                    r.intersectBody(body, result);
                    test.ok(result.hasHit, 'missed triangle ' + [i, j].join(','));
                }
            }
        }

        test.done();
    },

    plane: function(test){
        var r = new Ray(new Vec3(0,0,5), new Vec3(0, 0, -5));
        r.skipBackfaces = true;
        var shape = new Plane();
        var body = new Body({ mass: 1 });
        body.addShape(shape);

        var result = new RaycastResult();
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0,0,0)));
        test.equal(result.distance, 5);

        result.reset();
        var body2 = new Body({ mass: 1 });
        body2.addShape(shape, new Vec3(0, 0, 1), new Quaternion());
        r.intersectBody(body2, result);
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0,0,1)));

        result.reset();
        var body3 = new Body({ mass: 1 });
        var quat = new Quaternion();
        quat.setFromAxisAngle(new Vec3(1, 0, 0), Math.PI / 2);
        body3.addShape(shape, new Vec3(), quat);
        r.intersectBody(body3, result);
        test.equals(result.hasHit, false);

        result.reset();
        var body4 = new Body({ mass: 1 });
        body4.addShape(shape);
        var r = new Ray(new Vec3(1, 1, 5), new Vec3(1, 1, -5));
        r.intersectBody(body4, result);
        test.equals(result.hasHit, true);
        test.deepEqual(result.hitPointWorld, new Vec3(1, 1, 0));
        test.equal(result.distance, 5);

        var result = new RaycastResult();
        r.from.set(0, 1, 1);
        r.to.set(0, -1, -1);
        body.position.set(0, 0, 0);
        r.intersectBody(body, result);
        var distance1 = result.distance;
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0,0,0)));

        var result = new RaycastResult();
        r.from.set(0, 1 - 5, 1);
        r.to.set(0, -1 - 5, -1);
        body.position.set(0, 0, 0);
        r.intersectBody(body, result);
        var distance2 = result.distance;
        test.equals(result.hasHit, true);
        test.ok(result.hitPointWorld.almostEquals(new Vec3(0,-5,0)));
        test.equal(distance1, distance2);

        test.done();
    },


    trimesh: function(test){
        var r = new Ray(new Vec3(0.5, 0.5, 10), new Vec3(0.5, 0.5, -10));
        r.skipBackfaces = true;

        var vertices = [
            0, 0, 0,
            1, 0, 0,
            0, 1, 0
        ];
        var indices = [
            0, 1, 2
        ];

        var body = new Body({
            mass: 1,
            shape: new Trimesh(vertices, indices)
        });

        // Hit
        var result = new RaycastResult();
        r.intersectBody(body, result);
        test.equals(result.hasHit, true);
        test.deepEqual(result.hitPointWorld, new Vec3(0.5, 0.5, 0));

        // Miss
        result = new RaycastResult();
        r.from.set(-100, -100, 10);
        r.to.set(-100, -100, -10);
        r.intersectBody(body, result);
        test.equals(result.hasHit, false);

        test.done();
    },

};

function createPolyhedron(size){
    size = (size===undefined ? 0.5 : size);
    var box = new Box(new Vec3(size,size,size));
    box.updateConvexPolyhedronRepresentation();
    return box.convexPolyhedronRepresentation;
}