three
Version:
JavaScript 3D library
292 lines (168 loc) • 5.7 kB
JavaScript
import { Vector3 } from './Vector3.js';
import { Line3 } from './Line3.js';
import { Plane } from './Plane.js';
/**
* @author bhouston / http://clara.io
* @author mrdoob / http://mrdoob.com/
*/
function Triangle( a, b, c ) {
this.a = ( a !== undefined ) ? a : new Vector3();
this.b = ( b !== undefined ) ? b : new Vector3();
this.c = ( c !== undefined ) ? c : new Vector3();
}
Object.assign( Triangle, {
getNormal: function () {
var v0 = new Vector3();
return function getNormal( a, b, c, target ) {
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .getNormal() target is now required' );
target = new Vector3();
}
target.subVectors( c, b );
v0.subVectors( a, b );
target.cross( v0 );
var targetLengthSq = target.lengthSq();
if ( targetLengthSq > 0 ) {
return target.multiplyScalar( 1 / Math.sqrt( targetLengthSq ) );
}
return target.set( 0, 0, 0 );
};
}(),
// static/instance method to calculate barycentric coordinates
// based on: http://www.blackpawn.com/texts/pointinpoly/default.html
getBarycoord: function () {
var v0 = new Vector3();
var v1 = new Vector3();
var v2 = new Vector3();
return function getBarycoord( point, a, b, c, target ) {
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 );
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .getBarycoord() target is now required' );
target = new Vector3();
}
// collinear 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 target.set( - 2, - 1, - 1 );
}
var invDenom = 1 / denom;
var u = ( dot11 * dot02 - dot01 * dot12 ) * invDenom;
var v = ( dot00 * dot12 - dot01 * dot02 ) * invDenom;
// barycentric coordinates must always sum to 1
return target.set( 1 - u - v, v, u );
};
}(),
containsPoint: function () {
var v1 = new Vector3();
return function containsPoint( point, a, b, c ) {
Triangle.getBarycoord( point, a, b, c, v1 );
return ( v1.x >= 0 ) && ( v1.y >= 0 ) && ( ( v1.x + v1.y ) <= 1 );
};
}()
} );
Object.assign( Triangle.prototype, {
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;
},
clone: function () {
return new this.constructor().copy( this );
},
copy: function ( triangle ) {
this.a.copy( triangle.a );
this.b.copy( triangle.b );
this.c.copy( triangle.c );
return this;
},
getArea: function () {
var v0 = new Vector3();
var v1 = new Vector3();
return function getArea() {
v0.subVectors( this.c, this.b );
v1.subVectors( this.a, this.b );
return v0.cross( v1 ).length() * 0.5;
};
}(),
getMidpoint: function ( target ) {
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .getMidpoint() target is now required' );
target = new Vector3();
}
return target.addVectors( this.a, this.b ).add( this.c ).multiplyScalar( 1 / 3 );
},
getNormal: function ( target ) {
return Triangle.getNormal( this.a, this.b, this.c, target );
},
getPlane: function ( target ) {
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .getPlane() target is now required' );
target = new Vector3();
}
return target.setFromCoplanarPoints( this.a, this.b, this.c );
},
getBarycoord: function ( point, target ) {
return Triangle.getBarycoord( point, this.a, this.b, this.c, target );
},
containsPoint: function ( point ) {
return Triangle.containsPoint( point, this.a, this.b, this.c );
},
intersectsBox: function ( box ) {
return box.intersectsTriangle( this );
},
closestPointToPoint: function () {
var plane = new Plane();
var edgeList = [ new Line3(), new Line3(), new Line3() ];
var projectedPoint = new Vector3();
var closestPoint = new Vector3();
return function closestPointToPoint( point, target ) {
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .closestPointToPoint() target is now required' );
target = new Vector3();
}
var minDistance = Infinity;
// project the point onto the plane of the triangle
plane.setFromCoplanarPoints( this.a, this.b, this.c );
plane.projectPoint( point, projectedPoint );
// check if the projection lies within the triangle
if ( this.containsPoint( projectedPoint ) === true ) {
// if so, this is the closest point
target.copy( projectedPoint );
} else {
// if not, the point falls outside the triangle. the target is the closest point to the triangle's edges or vertices
edgeList[ 0 ].set( this.a, this.b );
edgeList[ 1 ].set( this.b, this.c );
edgeList[ 2 ].set( this.c, this.a );
for ( var i = 0; i < edgeList.length; i ++ ) {
edgeList[ i ].closestPointToPoint( projectedPoint, true, closestPoint );
var distance = projectedPoint.distanceToSquared( closestPoint );
if ( distance < minDistance ) {
minDistance = distance;
target.copy( closestPoint );
}
}
}
return target;
};
}(),
equals: function ( triangle ) {
return triangle.a.equals( this.a ) && triangle.b.equals( this.b ) && triangle.c.equals( this.c );
}
} );
export { Triangle };