feat: initialize project with core dependencies and game entry point

node_modules/three/examples/jsm/tsl/utils/Raymarching.js

@@ -0,0 +1,70 @@
+import { varying, vec4, modelWorldMatrixInverse, cameraPosition, positionGeometry, float, Fn, Loop, max, min, vec2, vec3 } from 'three/tsl';
+
+/**
+ * @module Raymarching
+ * @three_import import { RaymarchingBox } from 'three/addons/tsl/utils/Raymarching.js';
+ */
+
+const hitBox = /*@__PURE__*/ Fn( ( { orig, dir } ) => {
+
+	const box_min = vec3( - 0.5 );
+	const box_max = vec3( 0.5 );
+
+	const inv_dir = dir.reciprocal();
+
+	const tmin_tmp = box_min.sub( orig ).mul( inv_dir );
+	const tmax_tmp = box_max.sub( orig ).mul( inv_dir );
+
+	const tmin = min( tmin_tmp, tmax_tmp );
+	const tmax = max( tmin_tmp, tmax_tmp );
+
+	const t0 = max( tmin.x, max( tmin.y, tmin.z ) );
+	const t1 = min( tmax.x, min( tmax.y, tmax.z ) );
+
+	return vec2( t0, t1 );
+
+} );
+
+/**
+ * TSL function for performing raymarching in a box-area using the specified number of steps
+ * and a callback function.
+ *
+ * ```js
+ * RaymarchingBox( count, ( { positionRay } ) => {
+ *
+ * } );
+ * ```
+ *
+ * @tsl
+ * @function
+ * @param {number|Node} steps - The number of steps for raymarching.
+ * @param {Function|FunctionNode} callback - The callback function to execute at each step.
+ */
+export const RaymarchingBox = ( steps, callback ) => {
+
+	const vOrigin = varying( vec3( modelWorldMatrixInverse.mul( vec4( cameraPosition, 1.0 ) ) ) );
+	const vDirection = varying( positionGeometry.sub( vOrigin ) );
+
+	const rayDir = vDirection.normalize();
+	const bounds = vec2( hitBox( { orig: vOrigin, dir: rayDir } ) ).toVar();
+
+	bounds.x.greaterThan( bounds.y ).discard();
+
+	bounds.assign( vec2( max( bounds.x, 0.0 ), bounds.y ) );
+
+	const inc = vec3( rayDir.abs().reciprocal() ).toVar();
+	const delta = float( min( inc.x, min( inc.y, inc.z ) ) ).toVar();
+
+	delta.divAssign( float( steps ) );
+
+	const positionRay = vec3( vOrigin.add( bounds.x.mul( rayDir ) ) ).toVar();
+
+	Loop( { type: 'float', start: bounds.x, end: bounds.y, update: delta }, () => {
+
+		callback( { positionRay } );
+
+		positionRay.addAssign( rayDir.mul( delta ) );
+
+	} );
+
+};