Renders arrows to visualize an object's vertex tangent vectors.
Requires that tangents have been specified in a [page:BufferAttribute custom attribute] or
have been calculated using [page:BufferGeometryUtils.computeTangents computeTangents].
This helper supports [page:BufferGeometry] only.
[example:webgl_helpers WebGL / helpers]
var geometry = new THREE.BoxBufferGeometry( 10, 10, 10, 2, 2, 2 );
var material = new THREE.MeshNormalMaterial();
var box = new THREE.Mesh( geometry, material );
var helper = new THREE.VertexTangentsHelper( box, 1, 0x00ffff, 1 );
scene.add( box );
scene.add( helper );
[page:Object3D object] -- object for which to render vertex tangents.
[page:Number size] -- (optional) length of the arrows. Default is *1*.
[page:Hex color] -- hex color of the arrows. Default is 0x00ffff.
[page:Number linewidth] -- (optional) width of the arrow lines. Default is *1*. (Setting lineWidth is currently not supported.)
See the base [page:LineSegments] class for common properties.
See [page:Object3D.matrixAutoUpdate]. Set to *false* here as the helper is using the objects's [page:Object3D.matrixWorld matrixWorld].
The object for which the vertex tangents are being visualized.
Length of the arrows. Default is *1*.
See the base [page:LineSegments] class for common methods.
Updates the vertex tangents preview based on the object's world transform.
[link:https://github.com/mrdoob/three.js/blob/master/examples/jsm/helpers/VertexTangentsHelper.js examples/jsm/helpers/VertexTangentsHelper.js]