From b44fcf3f82f792baa4410dd19010d79b3315b364 Mon Sep 17 00:00:00 2001
From: Brice Chevalier <brice.chevalier@blackstormlabs.com>
Date: Mon, 20 Nov 2017 11:52:44 +0900
Subject: [PATCH] aglorithm optimization of Pairs.update method

---
 src/collision/Pair.js  | 1 +
 src/collision/Pairs.js | 8 ++++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/collision/Pair.js b/src/collision/Pair.js
index 7f654b5..ccfd088 100644
--- a/src/collision/Pair.js
+++ b/src/collision/Pair.js
@@ -33,6 +33,7 @@ var Contact = require('./Contact');
             activeContacts: [],
             separation: 0,
             isActive: true,
+            confirmedActive: true,
             isSensor: bodyA.isSensor || bodyB.isSensor,
             timeCreated: timestamp,
             timeUpdated: timestamp,
diff --git a/src/collision/Pairs.js b/src/collision/Pairs.js
index 48bd2ac..6e05e60 100644
--- a/src/collision/Pairs.js
+++ b/src/collision/Pairs.js
@@ -55,12 +55,15 @@ var Common = require('../core/Common');
         collisionEnd.length = 0;
         collisionActive.length = 0;
 
+        for (i = 0; i < pairsList.length; i++) {
+          pairsList[i].confirmedActive = false;
+        }
+
         for (i = 0; i < collisions.length; i++) {
             collision = collisions[i];
 
             if (collision.collided) {
                 pairId = Pair.id(collision.bodyA, collision.bodyB);
-                activePairIds.push(pairId);
 
                 pair = pairsTable[pairId];
                 
@@ -76,6 +79,7 @@ var Common = require('../core/Common');
 
                     // update the pair
                     Pair.update(pair, collision, timestamp);
+                    pair.confirmedActive = true;
                 } else {
                     // pair did not exist, create a new pair
                     pair = Pair.create(collision, timestamp);
@@ -91,7 +95,7 @@ var Common = require('../core/Common');
         // deactivate previously active pairs that are now inactive
         for (i = 0; i < pairsList.length; i++) {
             pair = pairsList[i];
-            if (pair.isActive && Common.indexOf(activePairIds, pair.id) === -1) {
+            if (!pair.confirmedActive) {
                 Pair.setActive(pair, false, timestamp);
                 collisionEnd.push(pair);
             }