first app vibe

app/node_modules/three/examples/jsm/helpers/VertexNormalsHelper.js

@@ -0,0 +1,155 @@
+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 };