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Copy pathTriangle.js
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190 lines (113 loc) · 3.73 KB
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/**
* @author bhouston / http://exocortex.com
* @author mrdoob / http://mrdoob.com/
*/
THREE.Triangle = function ( a, b, c ) {
this.a = ( a !== undefined ) ? a : new THREE.Vector3();
this.b = ( b !== undefined ) ? b : new THREE.Vector3();
this.c = ( c !== undefined ) ? c : new THREE.Vector3();
};
THREE.Triangle.normal = function() {
var v0 = new THREE.Vector3();
return function ( a, b, c, optionalTarget ) {
var result = optionalTarget || new THREE.Vector3();
result.subVectors( c, b );
v0.subVectors( a, b );
result.cross( v0 );
var resultLengthSq = result.lengthSq();
if( resultLengthSq > 0 ) {
return result.multiplyScalar( 1 / Math.sqrt( resultLengthSq ) );
}
return result.set( 0, 0, 0 );
};
}();
// static/instance method to calculate barycoordinates
// based on: http://www.blackpawn.com/texts/pointinpoly/default.html
THREE.Triangle.barycoordFromPoint = function() {
var v0 = new THREE.Vector3();
var v1 = new THREE.Vector3();
var v2 = new THREE.Vector3();
return function ( point, a, b, c, optionalTarget ) {
v0.subVectors( c, a );
v1.subVectors( b, a );
v2.subVectors( point, a );
var dot00 = v0.dot( v0 );
var dot01 = v0.dot( v1 );
var dot02 = v0.dot( v2 );
var dot11 = v1.dot( v1 );
var dot12 = v1.dot( v2 );
var denom = ( dot00 * dot11 - dot01 * dot01 );
var result = optionalTarget || new THREE.Vector3();
// colinear or singular triangle
if( denom == 0 ) {
// arbitrary location outside of triangle?
// not sure if this is the best idea, maybe should be returning undefined
return result.set( -2, -1, -1 );
}
var invDenom = 1 / denom;
var u = ( dot11 * dot02 - dot01 * dot12 ) * invDenom;
var v = ( dot00 * dot12 - dot01 * dot02 ) * invDenom;
// barycoordinates must always sum to 1
return result.set( 1 - u - v, v, u );
};
}();
THREE.Triangle.containsPoint = function() {
var v1 = new THREE.Vector3();
return function ( point, a, b, c ) {
var result = THREE.Triangle.barycoordFromPoint( point, a, b, c, v1 );
return ( result.x >= 0 ) && ( result.y >= 0 ) && ( ( result.x + result.y ) <= 1 );
};
}();
THREE.Triangle.prototype = {
constructor: THREE.Triangle,
set: function ( a, b, c ) {
this.a.copy( a );
this.b.copy( b );
this.c.copy( c );
return this;
},
setFromPointsAndIndices: function ( points, i0, i1, i2 ) {
this.a.copy( points[i0] );
this.b.copy( points[i1] );
this.c.copy( points[i2] );
return this;
},
copy: function ( triangle ) {
this.a.copy( triangle.a );
this.b.copy( triangle.b );
this.c.copy( triangle.c );
return this;
},
area: function() {
var v0 = new THREE.Vector3();
var v1 = new THREE.Vector3();
return function () {
v0.subVectors( this.c, this.b );
v1.subVectors( this.a, this.b );
return v0.cross( v1 ).length() * 0.5;
};
}(),
midpoint: function ( optionalTarget ) {
var result = optionalTarget || new THREE.Vector3();
return result.addVectors( this.a, this.b ).add( this.c ).multiplyScalar( 1 / 3 );
},
normal: function ( optionalTarget ) {
return THREE.Triangle.normal( this.a, this.b, this.c, optionalTarget );
},
plane: function ( optionalTarget ) {
var result = optionalTarget || new THREE.Plane();
return result.setFromCoplanarPoints( this.a, this.b, this.c );
},
barycoordFromPoint: function ( point, optionalTarget ) {
return THREE.Triangle.barycoordFromPoint( point, this.a, this.b, this.c, optionalTarget );
},
containsPoint: function ( point ) {
return THREE.Triangle.containsPoint( point, this.a, this.b, this.c );
},
equals: function ( triangle ) {
return triangle.a.equals( this.a ) && triangle.b.equals( this.b ) && triangle.c.equals( this.c );
},
clone: function () {
return new THREE.Triangle().copy( this );
}
};