From 15733593540c09ef7dcb796710fba8675093cd7a Mon Sep 17 00:00:00 2001
From: Marcin Misiurski <misiur66+github@gmail.com>
Date: Wed, 21 Oct 2015 00:15:20 +0200
Subject: [PATCH] Add permeable objects

---
 src/body/Body.js          |  1 +
 src/collision/Resolver.js | 16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/body/Body.js b/src/body/Body.js
index f7e3ae54..3459cc54 100644
--- a/src/body/Body.js
+++ b/src/body/Body.js
@@ -53,6 +53,7 @@ var Axes = require('../geometry/Axes');
             angularSpeed: 0,
             velocity: { x: 0, y: 0 },
             angularVelocity: 0,
+            isPermeable: false,
             isStatic: false,
             isSleeping: false,
             motion: 0,
diff --git a/src/collision/Resolver.js b/src/collision/Resolver.js
index e86dbd10..2c9b7b5c 100644
--- a/src/collision/Resolver.js
+++ b/src/collision/Resolver.js
@@ -72,11 +72,14 @@ var Bounds = require('../geometry/Bounds');
             
             if (!pair.isActive)
                 continue;
-            
+
             collision = pair.collision;
             bodyA = collision.parentA;
             bodyB = collision.parentB;
             normal = collision.normal;
+            
+            if (bodyA.isPermeable || bodyB.isPermeable)
+                continue;
 
             // get current separation between body edges involved in collision
             bodyBtoA = Vector.sub(Vector.add(bodyB.positionImpulse, bodyB.position, tempA), 
@@ -98,6 +101,9 @@ var Bounds = require('../geometry/Bounds');
             normal = collision.normal;
             positionImpulse = (pair.separation - pair.slop) * timeScale;
         
+            if (bodyA.isPermeable || bodyB.isPermeable)
+                continue;
+
             if (bodyA.isStatic || bodyB.isStatic)
                 positionImpulse *= 2;
             
@@ -189,7 +195,10 @@ var Bounds = require('../geometry/Bounds');
             bodyB = collision.parentB;
             normal = collision.normal;
             tangent = collision.tangent;
-                
+            
+            if (bodyA.isPermeable || bodyB.isPermeable)
+                continue;
+
             // resolve each contact
             for (j = 0; j < contacts.length; j++) {
                 contact = contacts[j];
@@ -250,6 +259,9 @@ var Bounds = require('../geometry/Bounds');
                 contacts = pair.activeContacts,
                 contactShare = 1 / contacts.length;
 
+            if (bodyA.isPermeable || bodyB.isPermeable)
+                continue;
+
             // update body velocities
             bodyA.velocity.x = bodyA.position.x - bodyA.positionPrev.x;
             bodyA.velocity.y = bodyA.position.y - bodyA.positionPrev.y;