Curve: Add optional target to getTangent() and getTangentAt().

docs/api/en/extras/core/Curve.html

@@ -79,15 +79,23 @@
 			using [page:.getPoint].
 		 </p>
 
-		<h3>[method:Vector getTangent]( [param:Float t] )</h3>
+		<h3>[method:Vector getTangent]( [param:Float t, [param:Vector optionalTarget] ] )</h3>
 		<p>
+			[page:Float t] - A position on the curve. Must be in the range [ 0, 1 ]. <br>
+			[page:Vector optionalTarget] — (optional) If specified, the result will be copied into this Vector,
+			otherwise a new Vector will be created. <br /><br />
+
 			Returns a unit vector tangent at t. If the derived curve does not implement its
 			tangent derivation, two points a small delta apart will be used to find its gradient
 			which seems to give a reasonable approximation.
 		</p>
 
-		<h3>[method:Vector getTangentAt]( [param:Float u] )</h3>
+		<h3>[method:Vector getTangentAt]( [param:Float u, [param:Vector optionalTarget] ] )</h3>
 		<p>
+			[page:Float u] - A position on the curve according to the arc length. Must be in the range [ 0, 1 ]. <br>
+			[page:Vector optionalTarget] — (optional) If specified, the result will be copied into this Vector,
+			otherwise a new Vector will be created. <br /><br />
+
 			Returns tangent at a point which is equidistant to the ends of the curve from the
 			point given in [page:.getTangent].
 		</p>

docs/api/zh/extras/core/Curve.html

@@ -77,17 +77,25 @@
 			Given u in the range ( 0 .. 1 ), returns [page:Float t] also in the range ( 0 .. 1 ).
 			u and t can then be used to give you points which are equidistant from the ends of the curve,
 			using [page:.getPoint].
-		 </p>
+		</p>
 
-		<h3>[method:Vector getTangent]( [param:Float t] )</h3>
+		<h3>[method:Vector getTangent]( [param:Float t, [param:Vector optionalTarget] ] )</h3>
 		<p>
+			[page:Float t] - A position on the curve. Must be in the range [ 0, 1 ]. <br>
+			[page:Vector optionalTarget] — (optional) If specified, the result will be copied into this Vector,
+			otherwise a new Vector will be created. <br /><br />
+
 			Returns a unit vector tangent at t. If the derived curve does not implement its
 			tangent derivation, two points a small delta apart will be used to find its gradient
 			which seems to give a reasonable approximation.
 		</p>
 
-		<h3>[method:Vector getTangentAt]( [param:Float u] )</h3>
+		<h3>[method:Vector getTangentAt]( [param:Float u, [param:Vector optionalTarget] ] )</h3>
 		<p>
+			[page:Float u] - A position on the curve according to the arc length. Must be in the range [ 0, 1 ]. <br>
+			[page:Vector optionalTarget] — (optional) If specified, the result will be copied into this Vector,
+			otherwise a new Vector will be created. <br /><br />
+
 			Returns tangent at a point which is equidistant to the ends of the curve from the
 			point given in [page:.getTangent].
 		</p>

examples/js/curves/NURBSCurve.js

@@ -59,12 +59,13 @@ THREE.NURBSCurve.prototype.getPoint = function ( t, optionalTarget ) {
 };
 
 
-THREE.NURBSCurve.prototype.getTangent = function ( t ) {
+THREE.NURBSCurve.prototype.getTangent = function ( t, optionalTarget ) {
+
+	var tangent = optionalTarget || new THREE.Vector3();
 
 	var u = this.knots[ 0 ] + t * ( this.knots[ this.knots.length - 1 ] - this.knots[ 0 ] );
 	var ders = THREE.NURBSUtils.calcNURBSDerivatives( this.degree, this.knots, this.controlPoints, u, 1 );
-	var tangent = ders[ 1 ].clone();
-	tangent.normalize();
+	tangent.copy( ders[ 1 ] ).normalize();
 
 	return tangent;
 

examples/jsm/curves/NURBSCurve.js

@@ -66,12 +66,13 @@ NURBSCurve.prototype.getPoint = function ( t, optionalTarget ) {
 };
 
 
-NURBSCurve.prototype.getTangent = function ( t ) {
+NURBSCurve.prototype.getTangent = function ( t, optionalTarget ) {
+
+	var tangent = optionalTarget || new Vector3();
 
 	var u = this.knots[ 0 ] + t * ( this.knots[ this.knots.length - 1 ] - this.knots[ 0 ] );
 	var ders = NURBSUtils.calcNURBSDerivatives( this.degree, this.knots, this.controlPoints, u, 1 );
-	var tangent = ders[ 1 ].clone();
-	tangent.normalize();
+	tangent.copy( ders[ 1 ] ).normalize();
 
 	return tangent;
 

examples/webgl_geometry_extrude_splines.html

@@ -37,6 +37,7 @@
 
 			var camera, scene, renderer, splineCamera, cameraHelper, cameraEye;
 
+			var direction = new THREE.Vector3();
 			var binormal = new THREE.Vector3();
 			var normal = new THREE.Vector3();
 			var position = new THREE.Vector3();
@@ -305,10 +306,10 @@
 				binormal.subVectors( tubeGeometry.binormals[ pickNext ], tubeGeometry.binormals[ pick ] );
 				binormal.multiplyScalar( pickt - pick ).add( tubeGeometry.binormals[ pick ] );
 
-				var dir = tubeGeometry.parameters.path.getTangentAt( t );
+				tubeGeometry.parameters.path.getTangentAt( t, direction );
 				var offset = 15;
 
-				normal.copy( binormal ).cross( dir );
+				normal.copy( binormal ).cross( direction );
 
 				// we move on a offset on its binormal
 
@@ -324,7 +325,7 @@
 
 				// camera orientation 2 - up orientation via normal
 
-				if ( ! params.lookAhead ) lookAt.copy( position ).add( dir );
+				if ( ! params.lookAhead ) lookAt.copy( position ).add( direction );
 				splineCamera.matrix.lookAt( splineCamera.position, lookAt, normal );
 				splineCamera.quaternion.setFromRotationMatrix( splineCamera.matrix );
 

src/extras/core/Curve.d.ts

@@ -17,13 +17,13 @@ export class Curve<T extends Vector> {
 
 	/**
 	 * Returns a vector for point t of the curve where t is between 0 and 1
-	 * getPoint(t: number): T;
+	 * getPoint(t: number, optionalTarget?: T): T;
 	 */
 	getPoint( t: number, optionalTarget?: T ): T;
 
 	/**
 	 * Returns a vector for point at relative position in curve according to arc length
-	 * getPointAt(u: number): T;
+	 * getPointAt(u: number, optionalTarget?: T): T;
 	 */
 	getPointAt( u: number, optionalTarget?: T ): T;
 
@@ -61,15 +61,15 @@ export class Curve<T extends Vector> {
 
 	/**
 	 * Returns a unit vector tangent at t. If the subclassed curve do not implement its tangent derivation, 2 points a small delta apart will be used to find its gradient which seems to give a reasonable approximation
-	 * getTangent(t: number): T;
+	 * getTangent(t: number, optionalTarget?: T): T;
 	 */
-	getTangent( t: number ): T;
+	getTangent( t: number, optionalTarget?: T ): T;
 
 	/**
 	 * Returns tangent at equidistance point u on the curve
-	 * getTangentAt(u: number): T;
+	 * getTangentAt(u: number, optionalTarget?: T): T;
 	 */
-	getTangentAt( u: number ): T;
+	getTangentAt( u: number, optionalTarget?: T ): T;
 
 	/**
 	 * @deprecated since r84.

src/extras/core/Curve.js

@@ -1,4 +1,5 @@
 import { MathUtils } from '../../math/MathUtils.js';
+import { Vector2 } from '../../math/Vector2.js';
 import { Vector3 } from '../../math/Vector3.js';
 import { Matrix4 } from '../../math/Matrix4.js';
 
@@ -7,8 +8,8 @@ import { Matrix4 } from '../../math/Matrix4.js';
  * Extensible curve object
  *
  * Some common of curve methods:
- * .getPoint( t, optionalTarget ), .getTangent( t )
- * .getPointAt( u, optionalTarget ), .getTangentAt( u )
+ * .getPoint( t, optionalTarget ), .getTangent( t, optionalTarget )
+ * .getPointAt( u, optionalTarget ), .getTangentAt( u, optionalTarget )
  * .getPoints(), .getSpacedPoints()
  * .getLength()
  * .updateArcLengths()
@@ -237,7 +238,7 @@ Object.assign( Curve.prototype, {
 	// 2 points a small delta apart will be used to find its gradient
 	// which seems to give a reasonable approximation
 
-	getTangent: function ( t ) {
+	getTangent: function ( t, optionalTarget ) {
 
 		var delta = 0.0001;
 		var t1 = t - delta;
@@ -251,15 +252,18 @@ Object.assign( Curve.prototype, {
 		var pt1 = this.getPoint( t1 );
 		var pt2 = this.getPoint( t2 );
 
-		var vec = pt2.clone().sub( pt1 );
-		return vec.normalize();
+		var tangent = optionalTarget || ( ( pt1.isVector2 ) ? new Vector2() : new Vector3() );
+
+		tangent.copy( pt2 ).sub( pt1 ).normalize();
+
+		return tangent;
 
 	},
 
-	getTangentAt: function ( u ) {
+	getTangentAt: function ( u, optionalTarget ) {
 
 		var t = this.getUtoTmapping( u );
-		return this.getTangent( t );
+		return this.getTangent( t, optionalTarget );
 
 	},
 
@@ -284,7 +288,7 @@ Object.assign( Curve.prototype, {
 
 			u = i / segments;
 
-			tangents[ i ] = this.getTangentAt( u );
+			tangents[ i ] = this.getTangentAt( u, new Vector3() );
 			tangents[ i ].normalize();
 
 		}

src/extras/curves/LineCurve.js

@@ -45,11 +45,13 @@ LineCurve.prototype.getPointAt = function ( u, optionalTarget ) {
 
 };
 
-LineCurve.prototype.getTangent = function ( /* t */ ) {
+LineCurve.prototype.getTangent = function ( t, optionalTarget ) {
 
-	var tangent = this.v2.clone().sub( this.v1 );
+	var tangent = optionalTarget || new Vector2();
 
-	return tangent.normalize();
+	var tangent = tangent.copy( this.v2 ).sub( this.v1 ).normalize();
+
+	return tangent;
 
 };