title: Three.js Animated curve
body: <p>I try to animate a 2D curve in Three.js over time.
  I'll need more than 4 control points, so I'm not using Bezier curves.
  I created a Three.Line based on a SplineCurve.</p>
  
  <p>If I log the geometry.vertices position of my line they'll change over time, but geometry.attributes.position remains the same. Is it possible to animate the line based on the curve animation ? I managed to do this with Bezier Curves, but can't find a way with SplineCurve.
  Thank you for your help, here's my code :</p>
  
  <p>First I create the line :</p>
  
  <pre><code>var curve = new THREE.SplineCurve( [
                  new THREE.Vector3( -10, 0, 10 ),
                  new THREE.Vector3( -5, 5, 5 ),
                  new THREE.Vector3( 0, 0, 0 ),
                  new THREE.Vector3( 5, -5, 5 ),
                  new THREE.Vector3( 10, 0, 10 )
              ] );
  
              var points = curve.getPoints( 50 );
  
              var geometry = new THREE.BufferGeometry().setFromPoints( points );
  
              var material = new THREE.LineBasicMaterial( { color : 0xff0000 } );
  
              // Create the final object to add to the scene
              curveObject = new THREE.Line( geometry, material );
  
              scene.add( curveObject );
  
              curveObject.curve = curve;
  </code></pre>
  
  <p>Then I try to update it :</p>
  
  <pre><code>curveObject.curve.points[0].x += 1;
  
  curveObject.geometry.vertices = curveObject.curve.getPoints( 50 );
  curveObject.geometry.verticesNeedUpdate = true;
  curveObject.geometry.attributes.needsUpdate = true;
  </code></pre>