ammo.js-bullet物理引擎碰撞检测

function updatePhysics(deltaTime) {
    physicsWorld.stepSimulation(deltaTime);
    //physicsWorld.performDiscreteCollisionDetection();
    var numManifolds=dispatcher.getNumManifolds();
    for(var i=0; i<numManifolds; i++){
        var contactManifold=dispatcher.getManifoldByIndexInternal(i);
        var objA=contactManifold.getBody0();
        var objB=contactManifold.getBody1();
        var numContacts = contactManifold.getNumContacts();
        //console.log(numContacts,objA,objB);
        for(var j=0; j<numContacts; j++)
        {
            var pt = contactManifold.getContactPoint(j);
            if(pt.getDistance()<=0.0){
                var posA = pt.getPositionWorldOnA();
                var posB = pt.getPositionWorldOnB();
                console.log("A:",i, posA.x(), posA.y(), posA.z()); // 碰撞点
                console.log("B:",i, posB.x(), posB.y(), posB.z());
            }
        }
    }

    // 更新物体位置
    for (var i = 0, iL = rigidBodies.length; i <iL; i++ ){
        var objThree = rigidBodies[i];
        var objPhys = objThree.userData.physicsBody;
        var ms = objPhys.getMotionState();
        if (ms) {
            ms.getWorldTransform(transformAux1);
            var p = transformAux1.getOrigin();
            var q = transformAux1.getRotation();
            objThree.position.set(p.x(), p.y(), p.z());
            objThree.quaternion.set(q.x(), q.y(), q.z(), q.w());
        }
    }
}

function createTriangleShapeByGeometry(geometry) {
    var mesh = new Ammo.btTriangleMesh(true, true);
    var vertices = geometry.vertices;
    for (var i = 0; i < geometry.faces.length; i++) {
        var face = geometry.faces[i];
        if (face instanceof THREE.Face3) {
            mesh.addTriangle(
                new Ammo.btVector3(vertices[face.a].x, vertices[face.a].y, vertices[face.a].z),
                new Ammo.btVector3(vertices[face.b].x, vertices[face.b].y, vertices[face.b].z),
                new Ammo.btVector3(vertices[face.c].x, vertices[face.c].y, vertices[face.c].z),
                false
            );
        } else if (face instanceof THREE.Face4) {
            mesh.addTriangle(
                new Ammo.btVector3(vertices[face.a].x, vertices[face.a].y, vertices[face.a].z),
                new Ammo.btVector3(vertices[face.b].x, vertices[face.b].y, vertices[face.b].z),
                new Ammo.btVector3(vertices[face.d].x, vertices[face.d].y, vertices[face.d].z),
                false
            );
            mesh.addTriangle(
                new Ammo.btVector3(vertices[face.b].x, vertices[face.b].y, vertices[face.b].z),
                new Ammo.btVector3(vertices[face.c].x, vertices[face.c].y, vertices[face.c].z),
                new Ammo.btVector3(vertices[face.d].x, vertices[face.d].y, vertices[face.d].z),
                false
            );
        }
    }
    var shape = new Ammo.btBvhTriangleMeshShape(mesh, true, true);
    return shape;
}    

var ballMass = 35;
var ballRadius = 0.4;

var path = new CustomSinCurve( 1.0 );
var geometry = new THREE.TubeGeometry( path, 20, 0.2, 8, false );
//var geometry=new THREE.SphereGeometry( ballRadius, 14, 10 );
var ball = new THREE.Mesh( geometry, ballMaterial );
ball.castShadow = true;
ball.receiveShadow = true;
var ballShape = createTriangleShapeByGeometry(geometry);//new Ammo.btSphereShape( ballRadius );
ballShape.setMargin( margin );
var pos = new THREE.Vector3();
var quat = new THREE.Quaternion();
pos.copy( raycaster.ray.direction );
pos.add( raycaster.ray.origin );
quat.set( 0, 0, 0, 1 );
var ballBody = createRigidBody( ball, ballShape, ballMass, pos, quat );

pos.copy( raycaster.ray.direction );
pos.multiplyScalar( 24 );
ballBody.setLinearVelocity( new Ammo.btVector3( pos.x, pos.y, pos.z ) );

function CustomSinCurve( scale ) {
    THREE.Curve.call( this );
    this.scale = ( scale === undefined ) ? 1 : scale;
}

CustomSinCurve.prototype = Object.create( THREE.Curve.prototype );
CustomSinCurve.prototype.constructor = CustomSinCurve;

CustomSinCurve.prototype.getPoint = function ( t ) {
    var tx = t * 3 - 1.5;
    var ty = Math.sin( 2 * Math.PI * t );
    var tz = 0;

    return new THREE.Vector3( tx, ty, tz ).multiplyScalar( this.scale );
};