From c10f6373a4b0a65a6fee051473a41a7ffc2b3b89 Mon Sep 17 00:00:00 2001
From: hkrish <hari.exeption@gmail.com>
Date: Sun, 5 May 2013 15:18:09 +0200
Subject: [PATCH] convex hull code working

---
 fatline/intersectTests.js | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/fatline/intersectTests.js b/fatline/intersectTests.js
index 2ad41340..ac362d90 100644
--- a/fatline/intersectTests.js
+++ b/fatline/intersectTests.js
@@ -63,7 +63,14 @@ function runTests() {
   }
 
 
-  convexhull( 20, 30 , 3 , -20 );
+  convexhull( 20, -30 , -30 , -20, 250, 80 );
+  convexhull( 20, -30 , -10 , -20, 250, 180 );
+  convexhull( 20, -15 , -40 , -20, 500, 80 );
+  convexhull( 20, -5 , -40 , -20, 500, 180 );
+  // convexhull( 20, 30 , 10 , -20, 250, 80 );
+  // convexhull( 20, 30 , 2 , -20, 250, 180 );
+  // convexhull( 20, 10 , 30 , -20, 500, 80 );
+  // convexhull( 20, 30 , 30 , -20, 500, 180 );
 
   view.draw();
 
@@ -143,7 +150,7 @@ function markIntersections( ixs ){
   }
 }
 
-function convexhull( dq0, dq1, dq2, dq3 ){
+function convexhull( dq0, dq1, dq2, dq3 , x, y){
   // Prepare the convex hull for D(ti, di(t))
   var distq1 = _getSignedDist( 0.0, dq0, 1.0, dq3, 0.3333333333333333, dq1 );
   var distq2 = _getSignedDist( 0.0, dq0, 1.0, dq3, 0.6666666666666666, dq2 );
@@ -161,7 +168,6 @@ function convexhull( dq0, dq1, dq2, dq3 ){
       distq1 = Math.abs(distq1);
       distq2 = Math.abs(distq2);
       var vqa1a2x, vqa1a2y, vqa1Maxx, vqa1Maxy, vqa1Minx, vqa1Miny;
-      console.log( " distq1 =  " + distq1 + " , distq2 = " + distq2 )
       if( distq1 > distq2 ){
           dqapex1 = [ 1.0, dq3 ];
           dqapex2 = [ 0.0, dq0 ];
@@ -174,20 +180,19 @@ function convexhull( dq0, dq1, dq2, dq3 ){
           dqmax = [ 0.6666666666666666, dq2 ];
       }
       // vector dqapex1->dqapex2
-      var vqa1a2x = dqapex1[0] - dqapex2[0], vqa1a2y = dqapex1[1] - dqapex2[1];
+      vqa1a2x = dqapex1[0] - dqapex2[0]; vqa1a2y = dqapex1[1] - dqapex2[1];
       // vector dqapex1->dqmax
-      var vqa1Maxx = dqapex1[0] - dqmax[0], vqa1Maxy = dqapex1[1] - dqmax[1];
+      vqa1Maxx = dqapex1[0] - dqmax[0]; vqa1Maxy = dqapex1[1] - dqmax[1];
       // vector dqapex1->dqmin
-      var vqa1Minx = dqapex1[1] - dqmin[0], vqa1Miny = dqapex1[1] - dqmin[1];
+      vqa1Minx = dqapex1[0] - dqmin[0]; vqa1Miny = dqapex1[1] - dqmin[1];
       // compare cross products of these vectors to determine, if
       // point is in triangles [ dq3, dqMax, dq0 ] or [ dq0, dqMax, dq3 ]
       var vcrossa1a2_a1Max = vqa1a2x * vqa1Maxy - vqa1a2y * vqa1Maxx;
       var vcrossa1a2_a1Min = vqa1a2x * vqa1Miny - vqa1a2y * vqa1Minx;
       var vcrossa1Max_a1Min = vqa1Maxx * vqa1Miny - vqa1Maxy * vqa1Minx;
       var sign1 = signum( vcrossa1Max_a1Min );
-      var sign2 = signum( vcrossa1a2_a1Min );
-      console.log( vcrossa1a2_a1Max, vcrossa1a2_a1Min, vcrossa1Max_a1Min )
-      if( sign1 === sign2 ){
+      var sign2 = signum( vcrossa1a2_a1Max );
+      if( sign1 !== sign2 ){
           // Point [2/3, dq2] is inside the triangle and the convex hull is a triangle
           Dt = [
               [ 0.0, dq0, dqmax[0], dqmax[1] ],
@@ -210,8 +215,8 @@ function convexhull( dq0, dq1, dq2, dq3 ){
   [ 0.6666666666666666, dq2, 1.0, dq3 ],
   [ 1.0, dq3, 0.0, dq0 ]
   ];
-  var yscale = 2;
-  var x = 500, y = 110;
+  var yscale = 1;
+  // var x = 500, y = 110;
   for (var i = 0; i < Dt.length; i++) {
       var pth = new Path.Line( new Point( x + Dt[i][0] * 190, y + Dt[i][1] * yscale ),
        new Point( x + Dt[i][2] * 190, y + Dt[i][3] * yscale ) );