Added logic to handle grid drawing where grid line starts on an object boundary

1 files changed, 177 insertions, 132 deletions

diff --git a/js/helper-classes/3D/StageLine.js b/js/helper-classes/3D/StageLine.js
index b86673d1..23e8cf5b 100755
--- a/js/helper-classes/3D/StageLine.js
+++ b/js/helper-classes/3D/StageLine.js
@@ -184,138 +184,183 @@ var StageLine = exports.StageLine = Object.create(Object.prototype, {
     },
 
         doCoplanarIntersection: {
-        value: function( plane )
-        {
-            // get the boundary points for the plane
-            var boundaryPts = plane.getBoundaryPoints();
-            var planeEq = plane.getPlaneEq();
-
-            if (plane.isBackFacing())
-            {
-                var tmp;
-                tmp = boundaryPts[0];  boundaryPts[0] = boundaryPts[3];  boundaryPts[3] = tmp;
-                tmp = boundaryPts[1];  boundaryPts[1] = boundaryPts[2];  boundaryPts[2] = tmp;
-            }
-
-            var pt0 = this.getPoint0(),
-                    pt1 = this.getPoint1();
-
-            // keep a couple flags to prevent counting crossings twice in edge cases
-            var gotEnter = false,
-                    gotExit = false;
-
-            var bp1 = boundaryPts[3];
-            for (var i=0;  i<4;  i++)
-            {
-                var bp0 = bp1;
-                bp1 = boundaryPts[i];
-                var vec = vecUtils.vecSubtract(3, bp1, bp0);
-                var nrm = vecUtils.vecCross(3, vec, planeEq);
-                nrm[3] = -vecUtils.vecDot(3, bp0, nrm);
-
-                var d0 = vecUtils.vecDot(3, nrm, pt0) + nrm[3],
-                        d1 = vecUtils.vecDot(3, nrm, pt1) + nrm[3];
-
-                var s0 = MathUtils.fpSign(d0),
-                        s1 = MathUtils.fpSign(d1);
-
-                if (s0 != s1)
-                {
-                    var t = Math.abs(d0)/( Math.abs(d0) + Math.abs(d1) );
-                    if ( (MathUtils.fpSign(t) >= 0) && (MathUtils.fpCmp(t,1.0) <= 0))
-                    {
-                        // get the point where the line crosses the edge of the element plane
-                        var pt = MathUtils.interpolateLine3D(pt0, pt1, t );
-
-                        // we know that the line crosses the infinite extension of the edge.  Determine
-                        // if that crossing is within the bounds of the edge
-                        var dot0 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp0),  vec),
-                                dot1 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp1),  vec);
-                        if ((MathUtils.fpSign(dot0) > 0) && (MathUtils.fpSign(dot1) < 0))
-                        {
-                            // determine if the line is entering or exiting
-                            if (s0 <= 0)                // entering
-                            {
-                                if (!gotEnter)
-                                {
-                                    gotEnter = true;
-                                    this.addIntersection( plane, t, 1 );
-                                }
-                            }
-                            else if (s0 > 0) // exiting
-                            {
-                                if (!gotExit)
-                                {
-                                    gotExit = true;
-                                    this.addIntersection( plane, t, -1 );
-                                }
-                            }
-                            else        // s0 == 0
-                            {
-                                // TODO
-                            }
-                        }
-                        else if ((MathUtils.fpSign(dot0) == 0) && (MathUtils.fpSign(dot1) < 0))
-                        {
-                            var j = i - 2;
-                            if (j < 0)  j += 4;
-                            var bp = boundaryPts[j];
-
-                            var v0 = vecUtils.vecSubtract( 3, bp, bp0 ),
-                                    v1 = vec;
-
-                            if (s0 <= 0)
-                            {
-                                var v = vecUtils.vecSubtract(3, pt1, pt0);
-                                if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
-                                {
-                                    gotEnter = true;
-                                    this.addIntersection( plane, t, 1 );
-                                }
-                            }
-                            else if (s0 > 0)
-                            {
-                                var v = vecUtils.vecSubtract(3, pt0, pt1);      // note the reversed order from the previous case
-                                if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
-                                {
-                                    gotEnter = true;
-                                    this.addIntersection( plane, t, -1 );
-                                }
-                            }
-                        }
-                        else if ((MathUtils.fpSign(dot0) > 0) && (MathUtils.fpSign(dot1) == 0))
-                        {
-                            var j = (i + 1) % 4;
-                            var bp = boundaryPts[j];
-
-                            var v1 = vec.slice(0),
-                                    v0 = vecUtils.vecSubtract( 3, bp, bp1 ),
-                                    v1 = vecUtils.vecNegate(3, v1);
-
-                            if (s0 <= 0)
-                            {
-                                var v = vecUtils.vecSubtract(3, pt1, pt0);
-                                if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) < 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) < 0))
-                                {
-                                    gotEnter = true;
-                                    this.addIntersection( plane, t, 1 );
-                                }
-                            }
-                            else if (s0 > 0)
-                            {
-                                var v = vecUtils.vecSubtract(3, pt0, pt1);      // note the reversed order from the previous case
-                                if ((MathUtils.fpSign(vecUtils.vecCross(3, v0,v)) > 0) && (MathUtils.fpSign(vecUtils.vecCross(3, v,v1)) > 0))
-                                {
-                                    gotEnter = true;
-                                    this.addIntersection( plane, t, -1 );
-                                }
-                            }
-                        }
+                value: function( plane )
+                {
+                        // get the boundary points for the plane
+                        var boundaryPts = plane.getBoundaryPoints();
+                        var planeEq = plane.getPlaneEq();
+
+                        if (plane.isBackFacing())
+                        {
+                                var tmp;
+                                tmp = boundaryPts[0];  boundaryPts[0] = boundaryPts[3];  boundaryPts[3] = tmp;
+                                tmp = boundaryPts[1];  boundaryPts[1] = boundaryPts[2];  boundaryPts[2] = tmp;
+                        }
+
+                        var pt0 = this.getPoint0(),
+                                pt1 = this.getPoint1();
+
+                        // keep a couple flags to prevent counting crossings twice in edge cases
+                        var gotEnter = false,
+                                        gotExit = false;
+
+                        var bp1 = boundaryPts[3];
+                        for (var i=0;  i<4;  i++)
+                        {
+                                var bp0 = bp1;
+                                bp1 = boundaryPts[i];
+                                var vec = vecUtils.vecSubtract(3, bp1, bp0);
+                                var nrm = vecUtils.vecCross(3, vec, planeEq);
+                                nrm[3] = -vecUtils.vecDot(3, bp0, nrm);
+
+                                var d0 = vecUtils.vecDot(3, nrm, pt0) + nrm[3],
+                                                d1 = vecUtils.vecDot(3, nrm, pt1) + nrm[3];
+
+                                var s0 = MathUtils.fpSign(d0),
+                                                s1 = MathUtils.fpSign(d1);
+
+                                if (s0 != s1)
+                                {
+                                        var t = Math.abs(d0)/( Math.abs(d0) + Math.abs(d1) );
+                                        if (t == 0)
+                                        {
+                                                if (s1 > 0)     // entering the material from the beginning of the line that is to be drawn
+                                                {
+                                                        // see if the start point of the line is at a corner of the bounded plane
+                                                        var lineDir = vecUtils.vecSubtract(3, pt1, pt0);
+                                                        vecUtils.vecNormalize(3, lineDir);
+                                                        var dist = vecUtils.vecDist( 3, pt0, bp1 );
+                                                        var bp2, bv0, bv1, cross1, cross2, cross3;
+                                                        if ( MathUtils.fpSign(dist) == 0)
+                                                        {
+                                                                bp2 = boundaryPts[(i+1) % 4];
+                                                                bv0 = vecUtils.vecSubtract(3, bp2, bp1);
+                                                                bv1 = vecUtils.vecSubtract(3, bp0, bp1);
+                                                                cross1 = vecUtils.vecCross(3, bv0, lineDir);
+                                                                cross2 = vecUtils.vecCross(3, lineDir, bv1);
+                                                                cross3 = vecUtils.vecCross(3, bv0, bv1);
+                                                                if ( (MathUtils.fpSign(vecUtils.vecDot(3, cross1, cross3)) == 0) && (MathUtils.fpSign(vecUtils.vecDot(3, cross2, cross3)) == 0))
+                                                                {
+                                                                        gotEnter = true;
+                                                                        this.addIntersection( plane, t, 1 );
+                                                                }
+                                                        }
+                                                        else if (MathUtils.fpSign( vecUtils.vecDist(3, pt0, bp0)) === 0)
+                                                        {
+                                                                bp2 = boundaryPts[(i+2) % 4];
+                                                                bv0 = vecUtils.vecSubtract(3, bp2, bp0);
+                                                                bv1 = vecUtils.vecSubtract(3, bp1, bp0);
+                                                                cross1 = vecUtils.vecCross(3, bv0, lineDir);
+                                                                cross2 = vecUtils.vecCross(3, lineDir, bv1);
+                                                                cross3 = vecUtils.vecCross(3, bv0, bv1);
+                                                                if ( (MathUtils.fpSign(vecUtils.vecDot(3, cross1, cross3)) == 0) && (MathUtils.fpSign(vecUtils.vecDot(3, cross2, cross3)) == 0))
+                                                                {
+                                                                        gotEnter = true;
+                                                                        this.addIntersection( plane, t, 1 );
+                                                                }
+                                                        }
+                                                        else
+                                                        {
+                                                                // check if the line is on the edge of the boundary or goes to the interior
+                                                                gotEnter = true;
+                                                                this.addIntersection( plane, t, 1 );
+                                                        }
+                                                }
+                                        }
+                                        else if ( (MathUtils.fpSign(t) > 0) && (MathUtils.fpCmp(t,1.0) <= 0))
+                                        {
+                                                // get the point where the line crosses the edge of the element plane
+                                                var pt = MathUtils.interpolateLine3D(pt0, pt1, t );
+
+                                                // we know that the line crosses the infinite extension of the edge.  Determine
+                                                // if that crossing is within the bounds of the edge
+                                                var dot0 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp0),  vec),
+                                                                dot1 = vecUtils.vecDot(3, vecUtils.vecSubtract(3,pt, bp1),  vec);
+                                                if ((MathUtils.fpSign(dot0) > 0) && (MathUtils.fpSign(dot1) < 0))
+                                                {
+                                                        // determine if the line is entering or exiting
+                                                        if (s0 <= 0)            // entering
+                                                        {
+                                                                if (!gotEnter)
+                                                                {
+                                                                        gotEnter = true;
+                                                                        this.addIntersection( plane, t, 1 );
+                                                                }
+                                                        }
+                                                        else if (s0 > 0) // exiting
+                                                        {
+                                                                if (!gotExit)
+                                                                {
+                                                                        gotExit = true;
+                                                                        this.addIntersection( plane, t, -1 );
+                                                                }
+                                                        }
+                                                        else    // s0 == 0
+                                                        {
+                                                                // TODO
+                                                        }
+                                                }
+                                                else if ((MathUtils.fpSign(dot0) == 0) && (MathUtils.fpSign(dot1) < 0))
+                                                {
+                                                        var j = i - 2;
+                                                        if (j < 0)  j += 4;
+                                                        var bp = boundaryPts[j];
+
+                                                        var v0 = vecUtils.vecSubtract( 3, bp, bp0 ),
+                                                                        v1 = vec;
+
+                                                        if (s0 <= 0)
+