scratchfoundation/paper.js
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convex hull code working

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hkrish 2013-05-05 15:18:09 +02:00
parent f08bc9b752
commit c10f6373a4
1 changed files with 16 additions and 11 deletions
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27
fatline/intersectTests.js
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@ -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 ) );