three
Version:
JavaScript 3D library
165 lines (97 loc) • 3.66 kB
JavaScript
/**
* @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
**************************************************************/
THREE.CurvePath = function () {
this.curves = [];
this.autoClose = false; // Automatically closes the path
};
THREE.CurvePath.prototype = Object.assign( Object.create( THREE.Curve.prototype ), {
constructor: THREE.CurvePath,
add: function ( curve ) {
this.curves.push( curve );
},
closePath: function () {
// TODO Test
// and verify for vector3 (needs to implement equals)
// 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 THREE.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 u = 1 - diff / curve.getLength();
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 ];
},
// 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;
},
/**************************************************************
* Create Geometries Helpers
**************************************************************/
/// Generate geometry from path points (for Line or Points objects)
createPointsGeometry: function ( divisions ) {
var pts = this.getPoints( divisions );
return this.createGeometry( pts );
},
// Generate geometry from equidistant sampling along the path
createSpacedPointsGeometry: function ( divisions ) {
var pts = this.getSpacedPoints( divisions );
return this.createGeometry( pts );
},
createGeometry: function ( points ) {
var geometry = new THREE.Geometry();
for ( var i = 0, l = points.length; i < l; i ++ ) {
var point = points[ i ];
geometry.vertices.push( new THREE.Vector3( point.x, point.y, point.z || 0 ) );
}
return geometry;
}
} );