three
Version:
JavaScript 3D library
262 lines (149 loc) • 4.98 kB
JavaScript
import { Curve } from './Curve.js';
import * as Curves from '../curves/Curves.js';
/**
* @author zz85 / http://www.lab4games.net/zz85/blog
*
**/
/**************************************************************
* Curved Path - a curve path is simply a array of connected
* curves, but retains the api of a curve
**************************************************************/
function CurvePath() {
Curve.call( this );
this.type = 'CurvePath';
this.curves = [];
this.autoClose = false; // Automatically closes the path
}
CurvePath.prototype = Object.assign( Object.create( Curve.prototype ), {
constructor: CurvePath,
add: function ( curve ) {
this.curves.push( curve );
},
closePath: function () {
// Add a line curve if start and end of lines are not connected
var startPoint = this.curves[ 0 ].getPoint( 0 );
var endPoint = this.curves[ this.curves.length - 1 ].getPoint( 1 );
if ( ! startPoint.equals( endPoint ) ) {
this.curves.push( new Curves[ 'LineCurve' ]( endPoint, startPoint ) );
}
},
// To get accurate point with reference to
// entire path distance at time t,
// following has to be done:
// 1. Length of each sub path have to be known
// 2. Locate and identify type of curve
// 3. Get t for the curve
// 4. Return curve.getPointAt(t')
getPoint: function ( t ) {
var d = t * this.getLength();
var curveLengths = this.getCurveLengths();
var i = 0;
// To think about boundaries points.
while ( i < curveLengths.length ) {
if ( curveLengths[ i ] >= d ) {
var diff = curveLengths[ i ] - d;
var curve = this.curves[ i ];
var segmentLength = curve.getLength();
var u = segmentLength === 0 ? 0 : 1 - diff / segmentLength;
return curve.getPointAt( u );
}
i ++;
}
return null;
// loop where sum != 0, sum > d , sum+1 <d
},
// We cannot use the default THREE.Curve getPoint() with getLength() because in
// THREE.Curve, getLength() depends on getPoint() but in THREE.CurvePath
// getPoint() depends on getLength
getLength: function () {
var lens = this.getCurveLengths();
return lens[ lens.length - 1 ];
},
// cacheLengths must be recalculated.
updateArcLengths: function () {
this.needsUpdate = true;
this.cacheLengths = null;
this.getCurveLengths();
},
// Compute lengths and cache them
// We cannot overwrite getLengths() because UtoT mapping uses it.
getCurveLengths: function () {
// We use cache values if curves and cache array are same length
if ( this.cacheLengths && this.cacheLengths.length === this.curves.length ) {
return this.cacheLengths;
}
// Get length of sub-curve
// Push sums into cached array
var lengths = [], sums = 0;
for ( var i = 0, l = this.curves.length; i < l; i ++ ) {
sums += this.curves[ i ].getLength();
lengths.push( sums );
}
this.cacheLengths = lengths;
return lengths;
},
getSpacedPoints: function ( divisions ) {
if ( divisions === undefined ) divisions = 40;
var points = [];
for ( var i = 0; i <= divisions; i ++ ) {
points.push( this.getPoint( i / divisions ) );
}
if ( this.autoClose ) {
points.push( points[ 0 ] );
}
return points;
},
getPoints: function ( divisions ) {
divisions = divisions || 12;
var points = [], last;
for ( var i = 0, curves = this.curves; i < curves.length; i ++ ) {
var curve = curves[ i ];
var resolution = ( curve && curve.isEllipseCurve ) ? divisions * 2
: ( curve && curve.isLineCurve ) ? 1
: ( curve && curve.isSplineCurve ) ? divisions * curve.points.length
: divisions;
var pts = curve.getPoints( resolution );
for ( var j = 0; j < pts.length; j ++ ) {
var point = pts[ j ];
if ( last && last.equals( point ) ) continue; // ensures no consecutive points are duplicates
points.push( point );
last = point;
}
}
if ( this.autoClose && points.length > 1 && ! points[ points.length - 1 ].equals( points[ 0 ] ) ) {
points.push( points[ 0 ] );
}
return points;
},
copy: function ( source ) {
Curve.prototype.copy.call( this, source );
this.curves = [];
for ( var i = 0, l = source.curves.length; i < l; i ++ ) {
var curve = source.curves[ i ];
this.curves.push( curve.clone() );
}
this.autoClose = source.autoClose;
return this;
},
toJSON: function () {
var data = Curve.prototype.toJSON.call( this );
data.autoClose = this.autoClose;
data.curves = [];
for ( var i = 0, l = this.curves.length; i < l; i ++ ) {
var curve = this.curves[ i ];
data.curves.push( curve.toJSON() );
}
return data;
},
fromJSON: function ( json ) {
Curve.prototype.fromJSON.call( this, json );
this.autoClose = json.autoClose;
this.curves = [];
for ( var i = 0, l = json.curves.length; i < l; i ++ ) {
var curve = json.curves[ i ];
this.curves.push( new Curves[ curve.type ]().fromJSON( curve ) );
}
return this;
}
} );
export { CurvePath };