1 files changed, 96 insertions, 1 deletions

diff --git a/js/helper-classes/3D/math-utils.js b/js/helper-classes/3D/math-utils.js
index 3d24f76e..37044763 100644
--- a/js/helper-classes/3D/math-utils.js
+++ b/js/helper-classes/3D/math-utils.js
@@ -8,7 +8,9 @@ No rights, expressed or implied, whatsoever to this software are provided by Mot
 // Class Utils
 //      Math Utility functions
 ///////////////////////////////////////////////////////////////////////
-var VecUtils = require("js/helper-classes/3D/vec-utils").VecUtils;
+var VecUtils = require("js/helper-classes/3D/vec-utils").VecUtils,
+        ViewUtils = require("js/helper-classes/3D/view-utils").ViewUtils,
+        Rectangle = require("js/helper-classes/3D/rectangle").Rectangle;
 
 var MathUtilsClass = exports.MathUtilsClass = Object.create(Object.prototype, {
     ///////////////////////////////////////////////////////////////////////
@@ -536,6 +538,99 @@ var MathUtilsClass = exports.MathUtilsClass = Object.create(Object.prototype, {
         }
     },
 
+        rectsOverlap:
+        {
+                value: function( pt, width, height,  elt )
+                {
+                        // only consider rectangles with non-zero area
+                        if ((width == 0) || (height == 0))  return false;
+
+                        // get the mins/maxs of the onput rectangle
+                        var xMin, xMax, yMin, yMax;
+                        if (width > 0)  {  xMin = pt[0];   xMax = pt[0] + width;  }
+                        else  {  xMax = pt[0];  xMin = pt[0] + width;  }
+                        if (height > 0)  {  yMin = pt[1];   yMax = pt[1] + height;  }
+                        else  {  yMax = pt[1];  yMin = pt[1] + height;  }
+
+                        // get the bounds of the element in global screen space
+                        var bounds = ViewUtils.getElementViewBounds3D( elt );
+                        var bounds3D = [];
+                        for (var i=0;  i<4;  i++)
+                                bounds3D[i] = ViewUtils.localToGlobal( bounds[i],  elt );
+
+                        // get the min/maxs for the element
+                        var xMinElt = bounds3D[0][0],  xMaxElt = bounds3D[0][0],
+                                yMinElt = bounds3D[0][1],  yMaxElt = bounds3D[0][1];
+                        for (var i=1;  i<4;  i++)
+                        {
+                                if (bounds3D[i][0] < xMinElt)  xMinElt = bounds3D[i][0];
+                                else if  (bounds3D[i][0] > xMaxElt)  xMaxElt = bounds3D[i][0];
+                                if (bounds3D[i][1] < yMinElt)  yMinElt = bounds3D[i][1];
+                                else if  (bounds3D[i][1] > yMaxElt)  yMaxElt = bounds3D[i][1];
+                        }
+
+                        // test 1.  Overall bounding box test
+                        if ((xMaxElt < xMin) || (xMinElt > xMax) || (yMaxElt < yMin) || (yMinElt > yMax))
+                                return false;
+                        
+                        // test 2.  See if any of the corners of the element are contained in the rectangle
+                        var rect = Object.create(Rectangle, {});
+                        rect.set( pt[0], pt[1], width, height );
+                        for (var i=0;  i<4;  i++)
+                        {
+                                if (rect.contains( bounds3D[i][0], bounds3D[i][1] ))  return true;
+                        }
+
+                        // test 3.  Bounding box tests on individual edges of the element
+                        for (var i=0;  i<4;  i++)
+                        {
+                                var pt0 = bounds3D[i],
+                                        pt1 = bounds3D[(i+1)%4];
+
+                                // get the extremes of the edge
+                                if (pt0[0] < pt1[0])  {  xMinElt = pt0[0];  xMaxElt = pt1[0];  }
+                                else {  xMaxElt = pt0[0];  xMinElt = pt1[0]; }
+                                if (pt0[1] < pt1[1])  {  yMinElt = pt0[1];  yMaxElt = pt1[1];  }
+                                else {  yMaxElt = pt0[1];  yMinElt = pt1[1]; }
+
+                                if ((xMaxElt < xMin) || (xMinElt > xMax) || (yMaxElt < yMin) || (yMinElt > yMax))
+                                        continue;
+                                else
+                                {
+                                        // intersect the element edge with the 4 sides of the rectangle
+                                        // vertical edges
+                                        var xRect = xMin;
+                                        for (var j=0;  j<2;  j++)
+                                        {
+                                                if ((xMinElt < xRect) && (xMaxElt > xRect))
+                                                {
+                                                        var t = (xRect - pt0[0])/(pt1[0] - pt0[0]);
+                                                        var y = pt0[1] + t*(pt1[1] - pt0[1]);
+                                                        if ((y >= yMin) && (y <= yMax))  return true;
+                                                }
+                                                xRect = xMax;
+                                        }
+
+                                        // horizontal edges
+                                        var yRect = yMin;
+                                        for (var j=0;  j<2;  j++)
+                                        {
+                                                if ((yMinElt < yRect) && (yMaxElt > yRect))
+                                                {
+                                                        var t = (yRect - pt0[1])/(pt1[1] - pt0[1]);
+                                                        var x = pt0[0] + t*(pt1[0] - pt0[0]);
+                                                        if ((x >= xMin) && (x <= xMax))  return true;
+                                                }
+                                                yRect = yMax;
+                                        }
+                                }
+                        }
+
+                        // if we get here there is no overlap
+                        return false;
+                }
+        },
+
     ///////////////////////////////////////////////////////////////////////
     // Bezier Methods
     ///////////////////////////////////////////////////////////////////////