From f49d053e1f0602b30d13e2d93b70d7068e0333d2 Mon Sep 17 00:00:00 2001
From: liabru <liabru@brm.io>
Date: Wed, 3 May 2017 21:13:29 +0100
Subject: [PATCH] added second pass for constraint solving

---
 src/constraint/Constraint.js |  8 +++-----
 src/core/Engine.js           | 11 ++++++++---
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/constraint/Constraint.js b/src/constraint/Constraint.js
index 61de118d..07509c74 100644
--- a/src/constraint/Constraint.js
+++ b/src/constraint/Constraint.js
@@ -21,10 +21,8 @@ var Common = require('../core/Common');
 
 (function() {
 
-    var _zeroVector = { x: 0, y: 0 };
-
     Constraint._warming = 0.4;
-    Constraint._torqueDampen = 0.8;
+    Constraint._torqueDampen = 1;
     Constraint._minLength = 0.000001;
 
     /**
@@ -121,8 +119,8 @@ var Common = require('../core/Common');
             fixedB = !constraint.bodyB || (constraint.bodyB && constraint.bodyB.isStatic);
 
             if (!fixedA && !fixedB) {
-            Constraint.solve(constraints[i], timeScale);
-        }
+                Constraint.solve(constraints[i], timeScale);
+            }
         }
     };
 
diff --git a/src/core/Engine.js b/src/core/Engine.js
index 42c9de10..2466fde5 100644
--- a/src/core/Engine.js
+++ b/src/core/Engine.js
@@ -149,7 +149,7 @@ var Body = require('../body/Body');
         // update all body position and rotation by integration
         _bodiesUpdate(allBodies, delta, timing.timeScale, correction, world.bounds);
 
-        // update all constraints
+        // update all constraints (first pass)
         Constraint.preSolveAll(allBodies);
         for (i = 0; i < engine.constraintIterations; i++) {
             Constraint.solveAll(allConstraints, timing.timeScale);
@@ -158,7 +158,6 @@ var Body = require('../body/Body');
 
         // broadphase pass: find potential collision pairs
         if (broadphase.controller) {
-
             // if world is dirty, we must flush the whole grid
             if (world.isModified)
                 broadphase.controller.clear(broadphase);
@@ -167,7 +166,6 @@ var Body = require('../body/Body');
             broadphase.controller.update(broadphase, allBodies, engine, world.isModified);
             broadphasePairs = broadphase.pairsList;
         } else {
-
             // if no broadphase set, we just pass all bodies
             broadphasePairs = allBodies;
         }
@@ -201,6 +199,13 @@ var Body = require('../body/Body');
         }
         Resolver.postSolvePosition(allBodies);
 
+        // update all constraints (second pass)
+        Constraint.preSolveAll(allBodies);
+        for (i = 0; i < engine.constraintIterations; i++) {
+            Constraint.solveAll(allConstraints, timing.timeScale);
+        }
+        Constraint.postSolveAll(allBodies);
+
         // iteratively resolve velocity between collisions
         Resolver.preSolveVelocity(pairs.list);
         for (i = 0; i < engine.velocityIterations; i++) {