Accueil / npm / three@0.186.1 / examples / jsm / helpers / VertexNormalsHelper.js
VertexNormalsHelper.js
import {
BufferGeometry,
Float32BufferAttribute,
LineSegments,
LineBasicMaterial,
Matrix3,
Vector3
} from 'three';
const _v1 = new Vector3();
const _v2 = new Vector3();
const _normalMatrix = new Matrix3();
/**
* Visualizes an object's vertex normals.
*
* Requires that normals have been specified in the geometry as a buffer attribute or
* have been calculated using {@link BufferGeometry#computeVertexNormals}.
* ```js
* const geometry = new THREE.BoxGeometry( 10, 10, 10, 2, 2, 2 );
* const material = new THREE.MeshStandardMaterial();
* const mesh = new THREE.Mesh( geometry, material );
* scene.add( mesh );
*
* const helper = new VertexNormalsHelper( mesh, 1, 0xff0000 );
* scene.add( helper );
* ```
*
* @augments LineSegments
* @three_import import { VertexNormalsHelper } from 'three/addons/helpers/VertexNormalsHelper.js';
*/
class VertexNormalsHelper extends LineSegments {
/**
* Constructs a new vertex normals helper.
*
* @param {Object3D} object - The object for which to visualize vertex normals.
* @param {number} [size=1] - The helper's size.
* @param {number|Color|string} [color=0xff0000] - The helper's color.
*/
constructor( object, size = 1, color = 0xff0000 ) {
const geometry = new BufferGeometry();
const nNormals = object.geometry.attributes.normal.count;
const positions = new Float32BufferAttribute( nNormals * 2 * 3, 3 );
geometry.setAttribute( 'position', positions );
super( geometry, new LineBasicMaterial( { color, toneMapped: false } ) );
/**
* The object for which to visualize vertex normals.
*
* @type {Object3D}
*/
this.object = object;
/**
* The helper's size.
*
* @type {number}
* @default 1
*/
this.size = size;
this.type = 'VertexNormalsHelper';
/**
* Overwritten and set to `false` since the object's world transformation
* is encoded in the helper's geometry data.
*
* @type {boolean}
* @default false
*/
this.matrixAutoUpdate = false;
/**
* This flag can be used for type testing.
*
* @type {boolean}
* @readonly
* @default true
*/
this.isVertexNormalsHelper = true;
this.update();
}
/**
* Updates the vertex normals preview based on the object's world transform.
*/
update() {
this.object.updateMatrixWorld( true );
_normalMatrix.getNormalMatrix( this.object.matrixWorld );
const matrixWorld = this.object.matrixWorld;
const position = this.geometry.attributes.position;
//
const objGeometry = this.object.geometry;
if ( objGeometry ) {
const objPos = objGeometry.attributes.position;
const objNorm = objGeometry.attributes.normal;
let idx = 0;
// for simplicity, ignore index and drawcalls, and render every normal
for ( let j = 0, jl = objPos.count; j < jl; j ++ ) {
_v1.fromBufferAttribute( objPos, j ).applyMatrix4( matrixWorld );
_v2.fromBufferAttribute( objNorm, j );
_v2.applyMatrix3( _normalMatrix ).normalize().multiplyScalar( this.size ).add( _v1 );
position.setXYZ( idx, _v1.x, _v1.y, _v1.z );
idx = idx + 1;
position.setXYZ( idx, _v2.x, _v2.y, _v2.z );
idx = idx + 1;
}
}
position.needsUpdate = true;
}
/**
* Frees the GPU-related resources allocated by this instance. Call this
* method whenever this instance is no longer used in your app.
*/
dispose() {
this.geometry.dispose();
this.material.dispose();
}
}
export { VertexNormalsHelper };