新增tire。修改transform.Component为es.ComponentTransform

source/src/Physics/Verlet/Composites/Tire.ts

@@ -0,0 +1,23 @@
+module es {
+    export class Tire extends Composite {
+        constructor(origin: Vector2, radius: number, segments: number, spokeStiffness: number = 1, treadStiffness: number = 1) {
+            super();
+
+            const stride = 2 * Math.PI / segments;
+            for (let i = 0; i < segments; i ++) {
+                const theta = i * stride;
+                this.addParticle(new Particle(new Vector2(origin.x + Math.cos(theta) * radius,
+                    origin.y + Math.sin(theta) * radius)));
+            }
+
+            const centerParticle = this.addParticle(new Particle(origin));
+
+            for (let i = 0; i < segments; i ++) {
+                this.addConstraint(new DistanceConstraint(this.particles[i], this.particles[(i + 1) % segments], treadStiffness));
+                this.addConstraint(new DistanceConstraint(this.particles[i], centerParticle, spokeStiffness))
+                    .setCollidesWithColliders(false);
+                this.addConstraint(new DistanceConstraint(this.particles[i], this.particles[(i + 5) % segments], treadStiffness));
+            }
+        }
+    }
+}