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web-app/node_modules/three/src/geometries/TorusKnotGeometry.js

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+import { BufferGeometry } from '../core/BufferGeometry.js';
+import { Float32BufferAttribute } from '../core/BufferAttribute.js';
+import { Vector3 } from '../math/Vector3.js';
+
+class TorusKnotGeometry extends BufferGeometry {
+
+	constructor( radius = 1, tube = 0.4, tubularSegments = 64, radialSegments = 8, p = 2, q = 3 ) {
+
+		super();
+
+		this.type = 'TorusKnotGeometry';
+
+		this.parameters = {
+			radius: radius,
+			tube: tube,
+			tubularSegments: tubularSegments,
+			radialSegments: radialSegments,
+			p: p,
+			q: q
+		};
+
+		tubularSegments = Math.floor( tubularSegments );
+		radialSegments = Math.floor( radialSegments );
+
+		// buffers
+
+		const indices = [];
+		const vertices = [];
+		const normals = [];
+		const uvs = [];
+
+		// helper variables
+
+		const vertex = new Vector3();
+		const normal = new Vector3();
+
+		const P1 = new Vector3();
+		const P2 = new Vector3();
+
+		const B = new Vector3();
+		const T = new Vector3();
+		const N = new Vector3();
+
+		// generate vertices, normals and uvs
+
+		for ( let i = 0; i <= tubularSegments; ++ i ) {
+
+			// the radian "u" is used to calculate the position on the torus curve of the current tubular segment
+
+			const u = i / tubularSegments * p * Math.PI * 2;
+
+			// now we calculate two points. P1 is our current position on the curve, P2 is a little farther ahead.
+			// these points are used to create a special "coordinate space", which is necessary to calculate the correct vertex positions
+
+			calculatePositionOnCurve( u, p, q, radius, P1 );
+			calculatePositionOnCurve( u + 0.01, p, q, radius, P2 );
+
+			// calculate orthonormal basis
+
+			T.subVectors( P2, P1 );
+			N.addVectors( P2, P1 );
+			B.crossVectors( T, N );
+			N.crossVectors( B, T );
+
+			// normalize B, N. T can be ignored, we don't use it
+
+			B.normalize();
+			N.normalize();
+
+			for ( let j = 0; j <= radialSegments; ++ j ) {
+
+				// now calculate the vertices. they are nothing more than an extrusion of the torus curve.
+				// because we extrude a shape in the xy-plane, there is no need to calculate a z-value.
+
+				const v = j / radialSegments * Math.PI * 2;
+				const cx = - tube * Math.cos( v );
+				const cy = tube * Math.sin( v );
+
+				// now calculate the final vertex position.
+				// first we orient the extrusion with our basis vectors, then we add it to the current position on the curve
+
+				vertex.x = P1.x + ( cx * N.x + cy * B.x );
+				vertex.y = P1.y + ( cx * N.y + cy * B.y );
+				vertex.z = P1.z + ( cx * N.z + cy * B.z );
+
+				vertices.push( vertex.x, vertex.y, vertex.z );
+
+				// normal (P1 is always the center/origin of the extrusion, thus we can use it to calculate the normal)
+
+				normal.subVectors( vertex, P1 ).normalize();
+
+				normals.push( normal.x, normal.y, normal.z );
+
+				// uv
+
+				uvs.push( i / tubularSegments );
+				uvs.push( j / radialSegments );
+
+			}
+
+		}
+
+		// generate indices
+
+		for ( let j = 1; j <= tubularSegments; j ++ ) {
+
+			for ( let i = 1; i <= radialSegments; i ++ ) {
+
+				// indices
+
+				const a = ( radialSegments + 1 ) * ( j - 1 ) + ( i - 1 );
+				const b = ( radialSegments + 1 ) * j + ( i - 1 );
+				const c = ( radialSegments + 1 ) * j + i;
+				const d = ( radialSegments + 1 ) * ( j - 1 ) + i;
+
+				// faces
+
+				indices.push( a, b, d );
+				indices.push( b, c, d );
+
+			}
+
+		}
+
+		// build geometry
+
+		this.setIndex( indices );
+		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
+		this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
+		this.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2 ) );
+
+		// this function calculates the current position on the torus curve
+
+		function calculatePositionOnCurve( u, p, q, radius, position ) {
+
+			const cu = Math.cos( u );
+			const su = Math.sin( u );
+			const quOverP = q / p * u;
+			const cs = Math.cos( quOverP );
+
+			position.x = radius * ( 2 + cs ) * 0.5 * cu;
+			position.y = radius * ( 2 + cs ) * su * 0.5;
+			position.z = radius * Math.sin( quOverP ) * 0.5;
+
+		}
+
+	}
+
+	copy( source ) {
+
+		super.copy( source );
+
+		this.parameters = Object.assign( {}, source.parameters );
+
+		return this;
+
+	}
+
+	static fromJSON( data ) {
+
+		return new TorusKnotGeometry( data.radius, data.tube, data.tubularSegments, data.radialSegments, data.p, data.q );
+
+	}
+
+}
+
+export { TorusKnotGeometry };