perf: optimize broadphase pair management

Author: zOadT

src/Settings.ts

@@ -53,7 +53,7 @@ export class Settings {
    * future position based on the current displacement. This is a dimensionless
    * multiplier.
    */
-  static aabbMultiplier: number = 2.0;
+  static aabbMultiplier: number = 4.0;
 
   /**
    * A small length used as a collision and constraint tolerance. Usually it is

src/collision/BroadPhase.ts

@@ -188,8 +188,8 @@ export class BroadPhase {
     this.m_callback = addPairCallback;
 
     // Perform tree queries for all moving proxies.
-    while (this.m_moveBuffer.length > 0) {
-      this.m_queryProxyId = this.m_moveBuffer.pop();
+    for (let i = 0; i < this.m_moveBuffer.length; ++i) {
+      this.m_queryProxyId = this.m_moveBuffer[i];
       if (this.m_queryProxyId === null) {
         continue;
       }
@@ -202,8 +202,8 @@ export class BroadPhase {
       this.m_tree.query(fatAABB, this.queryCallback);
     }
 
-    // Try to keep the tree balanced.
-    // this.m_tree.rebalance(4);
+    // Reset move buffer
+    this.m_moveBuffer.length = 0;
   }
 
   queryCallback = (proxyId: number): boolean => {
@@ -212,11 +212,15 @@ export class BroadPhase {
       return true;
     }
 
+    const moved = this.m_tree.wasMoved(proxyId);
+    if (moved && proxyId > this.m_queryProxyId) {
+      // Both proxies are moving. Avoid duplicate pairs.
+      return true;
+    }
+
     const proxyIdA = Math.min(proxyId, this.m_queryProxyId);
     const proxyIdB = Math.max(proxyId, this.m_queryProxyId);
 
-    // TODO: Skip any duplicate pairs.
-
     const userDataA = this.m_tree.getUserData(proxyIdA);
     const userDataB = this.m_tree.getUserData(proxyIdB);
 

src/collision/DynamicTree.ts

@@ -48,6 +48,8 @@ export class TreeNode<T> {
   /** 0: leaf, -1: free node */
   height: number = -1;
 
+  moved: boolean = false;
+
   constructor(id?: number) {
     this.id = id;
   }
@@ -104,6 +106,18 @@ export class DynamicTree<T> {
     return node.userData;
   }
 
+  wasMoved(proxyId: number): boolean {
+    const node = this.m_nodes[proxyId];
+    _ASSERT && console.assert(!!node);
+    return node.moved;
+  }
+
+  clearMoved(proxyId: number): void {
+    const node = this.m_nodes[proxyId];
+    _ASSERT && console.assert(!!node);
+    node.moved = false;
+  }
+
   /**
    * Get the fat AABB for a node id.
    *
@@ -122,7 +136,8 @@ export class DynamicTree<T> {
     node.parent = null;
     node.child1 = null;
     node.child2 = null;
-    node.height = -1;
+    node.height = 0;
+    node.moved = false;
     this.m_nodes[node.id] = node;
     return node;
   }
@@ -152,6 +167,7 @@ export class DynamicTree<T> {
 
     node.userData = userData;
     node.height = 0;
+    node.moved = true;
 
     this.insertLeaf(node);
 
@@ -176,48 +192,65 @@ export class DynamicTree<T> {
    * fattened AABB, then the proxy is removed from the tree and re-inserted.
    * Otherwise the function returns immediately.
    *
-   * @param d Displacement
+   * @param displacement Displacement
    *
    * @return true if the proxy was re-inserted.
    */
-  moveProxy(id: number, aabb: AABB, d: Vec2): boolean {
+  moveProxy(id: number, aabb: AABB, displacement: Vec2): boolean {
     _ASSERT && console.assert(AABB.isValid(aabb));
-    _ASSERT && console.assert(!d || Vec2.isValid(d));
+    _ASSERT && console.assert(!displacement || Vec2.isValid(displacement));
 
     const node = this.m_nodes[id];
 
     _ASSERT && console.assert(!!node);
     _ASSERT && console.assert(node.isLeaf());
 
-    if (node.aabb.contains(aabb)) {
-      return false;
-    }
-
-    this.removeLeaf(node);
-
-    node.aabb.set(aabb);
-
     // Extend AABB.
-    aabb = node.aabb;
-    AABB.extend(aabb, Settings.aabbExtension);
+    const fatAABB = new AABB()
+    fatAABB.set(aabb);
+    AABB.extend(fatAABB, Settings.aabbExtension);
 
-    // Predict AABB displacement.
+    // Predict AABB movement
     // const d = Vec2.mul(Settings.aabbMultiplier, displacement);
 
-    if (d.x < 0.0) {
-      aabb.lowerBound.x += d.x * Settings.aabbMultiplier;
+    if (displacement.x < 0.0) {
+      fatAABB.lowerBound.x += displacement.x * Settings.aabbMultiplier;
     } else {
-      aabb.upperBound.x += d.x * Settings.aabbMultiplier;
+      fatAABB.upperBound.x += displacement.x * Settings.aabbMultiplier;
     }
 
-    if (d.y < 0.0) {
-      aabb.lowerBound.y += d.y * Settings.aabbMultiplier;
+    if (displacement.y < 0.0) {
+      fatAABB.lowerBound.y += displacement.y * Settings.aabbMultiplier;
     } else {
-      aabb.upperBound.y += d.y * Settings.aabbMultiplier;
+      fatAABB.upperBound.y += displacement.y * Settings.aabbMultiplier;
+    }
+
+    const treeAABB = node.aabb;
+    if (treeAABB.contains(aabb)) {
+      // The tree AABB still contains the object, but it might be too large.
+      // Perhaps the object was moving fast but has since gone to sleep.
+      // The huge AABB is larger than the new fat AABB.
+      const hugeAABB = new AABB();
+      hugeAABB.set(fatAABB);
+      AABB.extend(hugeAABB, 4.0 * Settings.aabbExtension);
+
+      if (hugeAABB.contains(treeAABB)) {
+        // The tree AABB contains the object AABB and the tree AABB is
+        // not too large. No tree update needed.
+        return false;
+      }
+
+      // Otherwise the tree AABB is huge and needs to be shrunk
     }
 
+    this.removeLeaf(node);
+
+    node.aabb = fatAABB;
+
     this.insertLeaf(node);
 
+    node.moved = true;
+
     return true;
   }
 

src/dynamics/Body.ts

@@ -590,13 +590,19 @@ export class Body {
    * Update fixtures in broad-phase.
    */
   synchronizeFixtures(): void {
-    const xf = Transform.identity();
+    const broadPhase = this.m_world.m_broadPhase;
 
-    this.m_sweep.getTransform(xf, 0);
+    if (this.m_awakeFlag) {
+      const xf = Transform.identity();
+      this.m_sweep.getTransform(xf, 0);
 
-    const broadPhase = this.m_world.m_broadPhase;
-    for (let f = this.m_fixtureList; f; f = f.m_next) {
-      f.synchronize(broadPhase, xf, this.m_xf);
+      for (let f = this.m_fixtureList; f; f = f.m_next) {
+        f.synchronize(broadPhase, xf, this.m_xf);
+      }
+    } else {
+      for (let f = this.m_fixtureList; f; f = f.m_next) {
+        f.synchronize(broadPhase, this.m_xf, this.m_xf);
+      }
     }
   }
 

src/dynamics/Fixture.ts

@@ -404,7 +404,7 @@ export class Fixture {
 
       proxy.aabb.combine(aabb1, aabb2);
 
-      const displacement = Vec2.sub(xf2.p, xf1.p);
+      const displacement = Vec2.sub(aabb2.getCenter(), aabb1.getCenter());
 
       broadPhase.moveProxy(proxy.proxyId, proxy.aabb, displacement);
     }