2 files changed, 64 insertions, 1 deletions

diff --git a/js/helper-classes/3D/math-utils.js b/js/helper-classes/3D/math-utils.js
index 37044763..de63f880 100755
--- a/js/helper-classes/3D/math-utils.js
+++ b/js/helper-classes/3D/math-utils.js
@@ -538,6 +538,39 @@ var MathUtilsClass = exports.MathUtilsClass = Object.create(Object.prototype, {
         }
     },
 
+    isIdentityMatrix: {
+        value: function( mat )
+        {
+            if(!mat)
+            {
+                return false;
+            }
+            else
+            {
+                if(mat[0] !== 1) return false;
+                if(mat[1] !== 0) return false;
+                if(mat[2] !== 0) return false;
+                if(mat[3] !== 0) return false;
+
+                if(mat[4] !== 0) return false;
+                if(mat[5] !== 1) return false;
+                if(mat[6] !== 0) return false;
+                if(mat[7] !== 0) return false;
+
+                if(mat[8] !== 0) return false;
+                if(mat[9] !== 0) return false;
+                if(mat[10] !== 1) return false;
+                if(mat[11] !== 0) return false;
+
+                if(mat[12] !== 0) return false;
+                if(mat[13] !== 0) return false;
+                if(mat[14] !== 0) return false;
+                if(mat[15] !== 1) return false;
+            }
+            return true;
+        }
+    },
+
         rectsOverlap:
         {
                 value: function( pt, width, height,  elt )
diff --git a/js/helper-classes/3D/snap-manager.js b/js/helper-classes/3D/snap-manager.js
index 372be345..596ba56a 100755
--- a/js/helper-classes/3D/snap-manager.js
+++ b/js/helper-classes/3D/snap-manager.js
@@ -40,6 +40,7 @@ var SnapManager = exports.SnapManager = Montage.create(Component, {
 
         // keep a reference to the most recent hitRecord.  Used for drawing feedback on the stage
         _lastHit : { value: null, writable: true },
+        _hitRecords : { value: [], writable: true },
 
         // keep a list of objects to avoid snapping to
         _avoidList : { value: [], writable: true },
@@ -274,6 +275,11 @@ var SnapManager = exports.SnapManager = Montage.create(Component, {
                         }       //if (hitRecArray.length == 0)
 
                         var rtnHit;
+
+            // Save reference to hit records to verify last hit record's element matches browser's elementFromPoint
+            this._hitRecords.length = 0;
+            this._hitRecords = hitRecArray;
+
                         if (hitRecArray.length > 0)
                         {
                                 this.sortHitRecords( hitRecArray );
@@ -2246,6 +2252,30 @@ var SnapManager = exports.SnapManager = Montage.create(Component, {
                                 drawUtils.setDrawingSurfaceElement(saveContext);
                         }
                 }
-        }
+        },
+
+    findHitRecordForElement: {
+        value: function(elt) {
+            var rtnHit;
+
+            if (!this._hitRecords)  return;
+            var nHits = this._hitRecords.length;
+
+            for (var i=0;  i<nHits;  i++)
+            {
+                var hi = this._hitRecords[i];
+                if(hi.getElement() === elt)
+                {
+                    rtnHit = hi;
+                    break;
+                }
+            }
+            // catch-all to turn off drag plane snapping
+            this.deactivateDragPlane();
+
+            this.setLastHit( rtnHit );
+            return rtnHit;
+        }
+    }
 
 });