import { Vector3 } from './Vector3.js';
const _v0 = /*@__PURE__*/ new Vector3();
const _v1 = /*@__PURE__*/ new Vector3();
const _v2 = /*@__PURE__*/ new Vector3();
const _v3 = /*@__PURE__*/ new Vector3();
const _vab = /*@__PURE__*/ new Vector3();
const _vac = /*@__PURE__*/ new Vector3();
const _vbc = /*@__PURE__*/ new Vector3();
const _vap = /*@__PURE__*/ new Vector3();
const _vbp = /*@__PURE__*/ new Vector3();
const _vcp = /*@__PURE__*/ new Vector3();
class Triangle {
constructor( a = new Vector3(), b = new Vector3(), c = new Vector3() ) {
this.a = a;
this.b = b;
this.c = c;
}
static getNormal( a, b, c, target ) {
target.subVectors( c, b );
_v0.subVectors( a, b );
target.cross( _v0 );
const 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
static getBarycoord( point, a, b, c, target ) {
_v0.subVectors( c, a );
_v1.subVectors( b, a );
_v2.subVectors( point, a );
const dot00 = _v0.dot( _v0 );
const dot01 = _v0.dot( _v1 );
const dot02 = _v0.dot( _v2 );
const dot11 = _v1.dot( _v1 );
const dot12 = _v1.dot( _v2 );
const denom = ( dot00 * dot11 - dot01 * dot01 );
// 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 );
}
const invDenom = 1 / denom;
const u = ( dot11 * dot02 - dot01 * dot12 ) * invDenom;
const v = ( dot00 * dot12 - dot01 * dot02 ) * invDenom;
// barycentric coordinates must always sum to 1
return target.set( 1 - u - v, v, u );
}
static containsPoint( point, a, b, c ) {
this.getBarycoord( point, a, b, c, _v3 );
return ( _v3.x >= 0 ) && ( _v3.y >= 0 ) && ( ( _v3.x + _v3.y ) <= 1 );
}
static getUV( point, p1, p2, p3, uv1, uv2, uv3, target ) {
this.getBarycoord( point, p1, p2, p3, _v3 );
target.set( 0, 0 );
target.addScaledVector( uv1, _v3.x );
target.addScaledVector( uv2, _v3.y );
target.addScaledVector( uv3, _v3.z );
return target;
}
static isFrontFacing( a, b, c, direction ) {
_v0.subVectors( c, b );
_v1.subVectors( a, b );
// strictly front facing
return ( _v0.cross( _v1 ).dot( direction ) < 0 ) ? true : false;
}
set( a, b, c ) {
this.a.copy( a );
this.b.copy( b );
this.c.copy( c );
return this;
}
setFromPointsAndIndices( points, i0, i1, i2 ) {
this.a.copy( points[ i0 ] );
this.b.copy( points[ i1 ] );
this.c.copy( points[ i2 ] );
return this;
}
setFromAttributeAndIndices( attribute, i0, i1, i2 ) {
this.a.fromBufferAttribute( attribute, i0 );
this.b.fromBufferAttribute( attribute, i1 );
this.c.fromBufferAttribute( attribute, i2 );
return this;
}
clone() {
return new this.constructor().copy( this );
}
copy( triangle ) {
this.a.copy( triangle.a );
this.b.copy( triangle.b );
this.c.copy( triangle.c );
return this;
}
getArea() {
_v0.subVectors( this.c, this.b );
_v1.subVectors( this.a, this.b );
return _v0.cross( _v1 ).length() * 0.5;
}
getMidpoint( target ) {
return target.addVectors( this.a, this.b ).add( this.c ).multiplyScalar( 1 / 3 );
}
getNormal( target ) {
return Triangle.getNormal( this.a, this.b, this.c, target );
}
getPlane( target ) {
return target.setFromCoplanarPoints( this.a, this.b, this.c );
}
getBarycoord( point, target ) {
return Triangle.getBarycoord( point, this.a, this.b, this.c, target );
}
getUV( point, uv1, uv2, uv3, target ) {
return Triangle.getUV( point, this.a, this.b, this.c, uv1, uv2, uv3, target );
}
containsPoint( point ) {
return Triangle.containsPoint( point, this.a, this.b, this.c );
}
isFrontFacing( direction ) {
return Triangle.isFrontFacing( this.a, this.b, this.c, direction );
}
intersectsBox( box ) {
return box.intersectsTriangle( this );
}
closestPointToPoint( p, target ) {
const a = this.a, b = this.b, c = this.c;
let 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 );
const d1 = _vab.dot( _vap );
const 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 );
const d3 = _vab.dot( _vbp );
const d4 = _vac.dot( _vbp );
if ( d3 >= 0 && d4 <= d3 ) {
// vertex region of B; barycentric coords (0, 1, 0)
return target.copy( b );
}
const 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 );
const d5 = _vab.dot( _vcp );
const d6 = _vac.dot( _vcp );
if ( d6 >= 0 && d5 <= d6 ) {
// vertex region of C; barycentric coords (0, 0, 1)
return target.copy( c );
}
const 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 );
}
const 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
const 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( triangle ) {
return triangle.a.equals( this.a ) && triangle.b.equals( this.b ) && triangle.c.equals( this.c );
}
}
export { Triangle };
