feat: initialize project with core dependencies and game entry point

node_modules/three/examples/jsm/objects/GroundedSkybox.js

@@ -0,0 +1,69 @@
+import { Mesh, MeshBasicMaterial, SphereGeometry, Vector3 } from 'three';
+
+/**
+ * A ground-projected skybox.
+ *
+ * By default the object is centered at the camera, so it is often helpful to set
+ * `skybox.position.y = height` to put the ground at the origin.
+ *
+ * ```js
+ * const height = 15, radius = 100;
+ *
+ * const skybox = new GroundedSkybox( envMap, height, radius );
+ * skybox.position.y = height;
+ * scene.add( skybox );
+ * ```
+ *
+ * @augments Mesh
+ * @three_import import { GroundedSkybox } from 'three/addons/objects/GroundedSkybox.js';
+ */
+class GroundedSkybox extends Mesh {
+
+	/**
+	 * Constructs a new ground-projected skybox.
+	 *
+	 * @param {Texture} map - The environment map to use.
+	 * @param {number} height - The height is how far the camera that took the photo was above the ground.
+	 * A larger value will magnify the downward part of the image.
+	 * @param {number} radius - The radius of the skybox. Must be large enough to ensure the scene's camera stays inside.
+	 * @param {number} [resolution=128] - The geometry resolution of the skybox.
+	 */
+	constructor( map, height, radius, resolution = 128 ) {
+
+		if ( height <= 0 || radius <= 0 || resolution <= 0 ) {
+
+			throw new Error( 'GroundedSkybox height, radius, and resolution must be positive.' );
+
+		}
+
+		const geometry = new SphereGeometry( radius, 2 * resolution, resolution );
+		geometry.scale( 1, 1, - 1 );
+
+		const pos = geometry.getAttribute( 'position' );
+		const tmp = new Vector3();
+
+		for ( let i = 0; i < pos.count; ++ i ) {
+
+			tmp.fromBufferAttribute( pos, i );
+			if ( tmp.y < 0 ) {
+
+				// Smooth out the transition from flat floor to sphere:
+				const y1 = - height * 3 / 2;
+				const f =
+						tmp.y < y1 ? - height / tmp.y : ( 1 - tmp.y * tmp.y / ( 3 * y1 * y1 ) );
+				tmp.multiplyScalar( f );
+				tmp.toArray( pos.array, 3 * i );
+
+			}
+
+		}
+
+		pos.needsUpdate = true;
+
+		super( geometry, new MeshBasicMaterial( { map, depthWrite: false } ) );
+
+	}
+
+}
+
+export { GroundedSkybox };