fixed: kinematic-body physics lagged a frame behind, allowing you to …

…walk through some bodies

Current position and velocity was synced to the physics object AFTER physics sim had been ran, allowing you to walk through some surfaces (particularly spheres and cylinders)
This now uses the new update mechanism to ensure physics bodies are synced before physics interactions are handled

src/misc/kinematic-body.js

@@ -39,7 +39,7 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
 
   init: function () {
     this.system = this.el.sceneEl.systems.physics;
-    this.system.addBehavior(this, this.system.Phase.SIMULATE);
+    this.system.addComponent(this);
 
     const el = this.el,
         data = this.data,
@@ -64,12 +64,12 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
 
   remove: function () {
     this.system.removeBody(this.body);
-    this.system.removeBehavior(this, this.system.Phase.SIMULATE);
+    this.system.removeComponent(this);
     delete this.el.body;
   },
 
   /*******************************************************************
-   * Tick
+   * Update
    */
 
   /**
@@ -82,7 +82,14 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
    *     If in contact with two ground surfaces (e.g. ground + ramp), choose
    *     the one that collides with current velocity, if any.
    */
-  step: (function () {
+  updateBefore: function (t, dt) {
+      if (!dt) return;
+
+      this.body.velocity.copy(this.el.getAttribute('velocity'));
+      this.body.position.copy(this.el.getAttribute('position'));
+  },
+
+  updateAfter: (function () {
     var velocity = new THREE.Vector3(),
         normalizedVelocity = new THREE.Vector3(),
         currentSurfaceNormal = new THREE.Vector3(),
@@ -95,16 +102,16 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
           data = this.data,
           didCollide = false,
           height, groundHeight = -Infinity,
-          groundBody;
+          groundBody,
+          contacts = this.system.getContacts();
 
       dt = Math.min(dt, this.system.data.maxInterval * 1000);
 
       groundNormal.set(0, 0, 0);
       velocity.copy(this.el.getAttribute('velocity'));
       body.velocity.copy(velocity);
-      body.position.copy(this.el.getAttribute('position'));
 
-      for (var i = 0, contact; (contact = this.system.world.contacts[i]); i++) {
+      for (var i = 0, contact; contact = contacts[i]; i++) {
         // 1. Find any collisions involving this element. Get the contact
         // normal, and make sure it's oriented _out_ of the other object and
         // enabled (body.collisionReponse is true for both bodies)
@@ -152,7 +159,7 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
       } else {
         // 5. If not in contact with anything horizontal, apply world gravity.
         // TODO - Why is the 4x scalar necessary.
-        velocity.add(this.system.world.gravity.scale(dt * 4.0 / 1000));
+        velocity.add(this.system.driver.world.gravity.scale(dt * 4.0 / 1000));
       }
 
       // 6. If the ground surface has a velocity, apply it directly to current
@@ -164,11 +171,12 @@ module.exports = AFRAME.registerComponent('kinematic-body', {
           y: body.position.y + groundVelocity.y * dt / 1000,
           z: body.position.z + groundVelocity.z * dt / 1000
         });
-        this.el.setAttribute('position', body.position);
       }
 
       body.velocity.copy(velocity);
-      this.el.setAttribute('velocity', velocity);
+
+      this.el.setAttribute('velocity', body.velocity);
+      this.el.setAttribute('position', body.position);
     };
   }()),