fireball/lib/math/Triangle.js
2018-12-25 17:29:22 +03:30

350 lines
7.1 KiB
JavaScript

import { Vector3 } from './Vector3.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 );
};
}(),
getUV: function () {
var barycoord = new Vector3();
return function getUV( point, p1, p2, p3, uv1, uv2, uv3, target ) {
this.getBarycoord( point, p1, p2, p3, barycoord );
target.set( 0, 0 );
target.addScaledVector( uv1, barycoord.x );
target.addScaledVector( uv2, barycoord.y );
target.addScaledVector( uv3, barycoord.z );
return target;
};
}()
} );
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 );
},
getUV: function ( point, uv1, uv2, uv3, result ) {
return Triangle.getUV( point, this.a, this.b, this.c, uv1, uv2, uv3, result );
},
intersectsBox: function ( box ) {
return box.intersectsTriangle( this );
},
closestPointToPoint: function () {
var vab = new Vector3();
var vac = new Vector3();
var vbc = new Vector3();
var vap = new Vector3();
var vbp = new Vector3();
var vcp = new Vector3();
return function closestPointToPoint( p, target ) {
if ( target === undefined ) {
console.warn( 'THREE.Triangle: .closestPointToPoint() target is now required' );
target = new Vector3();
}
var a = this.a, b = this.b, c = this.c;
var v, w;
// algorithm thanks to Real-Time Collision Detection by Christer Ericson,
// published by Morgan Kaufmann Publishers, (c) 2005 Elsevier Inc.,
// under the accompanying license; see chapter 5.1.5 for detailed explanation.
// basically, we're distinguishing which of the voronoi regions of the triangle
// the point lies in with the minimum amount of redundant computation.
vab.subVectors( b, a );
vac.subVectors( c, a );
vap.subVectors( p, a );
var d1 = vab.dot( vap );
var d2 = vac.dot( vap );
if ( d1 <= 0 && d2 <= 0 ) {
// vertex region of A; barycentric coords (1, 0, 0)
return target.copy( a );
}
vbp.subVectors( p, b );
var d3 = vab.dot( vbp );
var d4 = vac.dot( vbp );
if ( d3 >= 0 && d4 <= d3 ) {
// vertex region of B; barycentric coords (0, 1, 0)
return target.copy( b );
}
var vc = d1 * d4 - d3 * d2;
if ( vc <= 0 && d1 >= 0 && d3 <= 0 ) {
v = d1 / ( d1 - d3 );
// edge region of AB; barycentric coords (1-v, v, 0)
return target.copy( a ).addScaledVector( vab, v );
}
vcp.subVectors( p, c );
var d5 = vab.dot( vcp );
var d6 = vac.dot( vcp );
if ( d6 >= 0 && d5 <= d6 ) {
// vertex region of C; barycentric coords (0, 0, 1)
return target.copy( c );
}
var vb = d5 * d2 - d1 * d6;
if ( vb <= 0 && d2 >= 0 && d6 <= 0 ) {
w = d2 / ( d2 - d6 );
// edge region of AC; barycentric coords (1-w, 0, w)
return target.copy( a ).addScaledVector( vac, w );
}
var va = d3 * d6 - d5 * d4;
if ( va <= 0 && ( d4 - d3 ) >= 0 && ( d5 - d6 ) >= 0 ) {
vbc.subVectors( c, b );
w = ( d4 - d3 ) / ( ( d4 - d3 ) + ( d5 - d6 ) );
// edge region of BC; barycentric coords (0, 1-w, w)
return target.copy( b ).addScaledVector( vbc, w ); // edge region of BC
}
// face region
var denom = 1 / ( va + vb + vc );
// u = va * denom
v = vb * denom;
w = vc * denom;
return target.copy( a ).addScaledVector( vab, v ).addScaledVector( vac, w );
};
}(),
equals: function ( triangle ) {
return triangle.a.equals( this.a ) && triangle.b.equals( this.b ) && triangle.c.equals( this.c );
}
} );
export { Triangle };