three.js/examples/jsm/misc/RollerCoaster.js

import {
	BufferAttribute,
	BufferGeometry,
	Color,
	Quaternion,
	Raycaster,
	SRGBColorSpace,
	Vector3
} from 'three';

/**
 * A procedural roller coaster geometry.
 *
 * @augments BufferGeometry
 */
class RollerCoasterGeometry extends BufferGeometry {

	/**
	 * Constructs a new geometry.
	 *
	 * @param {Curve} curve - The curve to generate the geometry along.
 	 * @param {number} divisions - The number of divisions which defines the detail of the geometry.
	 */
	constructor( curve, divisions ) {

		super();

		const vertices = [];
		const normals = [];
		const colors = [];

		const color1 = [ 1, 1, 1 ];
		const color2 = [ 1, 1, 0 ];

		const up = new Vector3( 0, 1, 0 );
		const forward = new Vector3();
		const right = new Vector3();

		const quaternion = new Quaternion();
		const prevQuaternion = new Quaternion();
		prevQuaternion.setFromAxisAngle( up, Math.PI / 2 );

		const point = new Vector3();
		const prevPoint = new Vector3();
		prevPoint.copy( curve.getPointAt( 0 ) );

		// shapes

		const step = [
			new Vector3( - 0.225, 0, 0 ),
			new Vector3( 0, - 0.050, 0 ),
			new Vector3( 0, - 0.175, 0 ),

			new Vector3( 0, - 0.050, 0 ),
			new Vector3( 0.225, 0, 0 ),
			new Vector3( 0, - 0.175, 0 )
		];

		const PI2 = Math.PI * 2;

		let sides = 5;
		const tube1 = [];

		for ( let i = 0; i < sides; i ++ ) {

			const angle = ( i / sides ) * PI2;
			tube1.push( new Vector3( Math.sin( angle ) * 0.06, Math.cos( angle ) * 0.06, 0 ) );

		}

		sides = 6;
		const tube2 = [];

		for ( let i = 0; i < sides; i ++ ) {

			const angle = ( i / sides ) * PI2;
			tube2.push( new Vector3( Math.sin( angle ) * 0.025, Math.cos( angle ) * 0.025, 0 ) );

		}

		const vector = new Vector3();
		const normal = new Vector3();

		function drawShape( shape, color ) {

			normal.set( 0, 0, - 1 ).applyQuaternion( quaternion );

			for ( let j = 0; j < shape.length; j ++ ) {

				vector.copy( shape[ j ] );
				vector.applyQuaternion( quaternion );
				vector.add( point );

				vertices.push( vector.x, vector.y, vector.z );
				normals.push( normal.x, normal.y, normal.z );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );

			}

			normal.set( 0, 0, 1 ).applyQuaternion( quaternion );

			for ( let j = shape.length - 1; j >= 0; j -- ) {

				vector.copy( shape[ j ] );
				vector.applyQuaternion( quaternion );
				vector.add( point );

				vertices.push( vector.x, vector.y, vector.z );
				normals.push( normal.x, normal.y, normal.z );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );

			}

		}

		const vector1 = new Vector3();
		const vector2 = new Vector3();
		const vector3 = new Vector3();
		const vector4 = new Vector3();

		const normal1 = new Vector3();
		const normal2 = new Vector3();
		const normal3 = new Vector3();
		const normal4 = new Vector3();

		function extrudeShape( shape, offset, color ) {

			for ( let j = 0, jl = shape.length; j < jl; j ++ ) {

				const point1 = shape[ j ];
				const point2 = shape[ ( j + 1 ) % jl ];

				vector1.copy( point1 ).add( offset );
				vector1.applyQuaternion( quaternion );
				vector1.add( point );

				vector2.copy( point2 ).add( offset );
				vector2.applyQuaternion( quaternion );
				vector2.add( point );

				vector3.copy( point2 ).add( offset );
				vector3.applyQuaternion( prevQuaternion );
				vector3.add( prevPoint );

				vector4.copy( point1 ).add( offset );
				vector4.applyQuaternion( prevQuaternion );
				vector4.add( prevPoint );

				vertices.push( vector1.x, vector1.y, vector1.z );
				vertices.push( vector2.x, vector2.y, vector2.z );
				vertices.push( vector4.x, vector4.y, vector4.z );

				vertices.push( vector2.x, vector2.y, vector2.z );
				vertices.push( vector3.x, vector3.y, vector3.z );
				vertices.push( vector4.x, vector4.y, vector4.z );

				//

				normal1.copy( point1 );
				normal1.applyQuaternion( quaternion );
				normal1.normalize();

				normal2.copy( point2 );
				normal2.applyQuaternion( quaternion );
				normal2.normalize();

				normal3.copy( point2 );
				normal3.applyQuaternion( prevQuaternion );
				normal3.normalize();

				normal4.copy( point1 );
				normal4.applyQuaternion( prevQuaternion );
				normal4.normalize();

				normals.push( normal1.x, normal1.y, normal1.z );
				normals.push( normal2.x, normal2.y, normal2.z );
				normals.push( normal4.x, normal4.y, normal4.z );

				normals.push( normal2.x, normal2.y, normal2.z );
				normals.push( normal3.x, normal3.y, normal3.z );
				normals.push( normal4.x, normal4.y, normal4.z );

				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );

				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );
				colors.push( color[ 0 ], color[ 1 ], color[ 2 ] );

			}

		}

		const offset = new Vector3();

		for ( let i = 1; i <= divisions; i ++ ) {

			point.copy( curve.getPointAt( i / divisions ) );

			up.set( 0, 1, 0 );

			forward.subVectors( point, prevPoint ).normalize();
			right.crossVectors( up, forward ).normalize();
			up.crossVectors( forward, right );

			const angle = Math.atan2( forward.x, forward.z );

			quaternion.setFromAxisAngle( up, angle );

			if ( i % 2 === 0 ) {

				drawShape( step, color2 );

			}

			extrudeShape( tube1, offset.set( 0, - 0.125, 0 ), color2 );
			extrudeShape( tube2, offset.set( 0.2, 0, 0 ), color1 );
			extrudeShape( tube2, offset.set( - 0.2, 0, 0 ), color1 );

			prevPoint.copy( point );
			prevQuaternion.copy( quaternion );

		}

		// console.log( vertices.length );

		this.setAttribute( 'position', new BufferAttribute( new Float32Array( vertices ), 3 ) );
		this.setAttribute( 'normal', new BufferAttribute( new Float32Array( normals ), 3 ) );
		this.setAttribute( 'color', new BufferAttribute( new Float32Array( colors ), 3 ) );

	}

}

/**
 * A procedural roller coaster lifters geometry.
 *
 * @augments BufferGeometry
 */
class RollerCoasterLiftersGeometry extends BufferGeometry {

	/**
	 * Constructs a new geometry.
	 *
	 * @param {Curve} curve - The curve to generate the geometry along.
 	 * @param {number} divisions - The number of divisions which defines the detail of the geometry.
	 */
	constructor( curve, divisions ) {

		super();

		const vertices = [];
		const normals = [];

		const quaternion = new Quaternion();

		const up = new Vector3( 0, 1, 0 );

		const point = new Vector3();
		const tangent = new Vector3();

		// shapes

		const tube1 = [
			new Vector3( 0, 0.05, - 0.05 ),
			new Vector3( 0, 0.05, 0.05 ),
			new Vector3( 0, - 0.05, 0 )
		];

		const tube2 = [
			new Vector3( - 0.05, 0, 0.05 ),
			new Vector3( - 0.05, 0, - 0.05 ),
			new Vector3( 0.05, 0, 0 )
		];

		const tube3 = [
			new Vector3( 0.05, 0, - 0.05 ),
			new Vector3( 0.05, 0, 0.05 ),
			new Vector3( - 0.05, 0, 0 )
		];

		const vector1 = new Vector3();
		const vector2 = new Vector3();
		const vector3 = new Vector3();
		const vector4 = new Vector3();

		const normal1 = new Vector3();
		const normal2 = new Vector3();
		const normal3 = new Vector3();
		const normal4 = new Vector3();

		function extrudeShape( shape, fromPoint, toPoint ) {

			for ( let j = 0, jl = shape.length; j < jl; j ++ ) {

				const point1 = shape[ j ];
				const point2 = shape[ ( j + 1 ) % jl ];

				vector1.copy( point1 );
				vector1.applyQuaternion( quaternion );
				vector1.add( fromPoint );

				vector2.copy( point2 );
				vector2.applyQuaternion( quaternion );
				vector2.add( fromPoint );

				vector3.copy( point2 );
				vector3.applyQuaternion( quaternion );
				vector3.add( toPoint );

				vector4.copy( point1 );
				vector4.applyQuaternion( quaternion );
				vector4.add( toPoint );

				vertices.push( vector1.x, vector1.y, vector1.z );
				vertices.push( vector2.x, vector2.y, vector2.z );
				vertices.push( vector4.x, vector4.y, vector4.z );

				vertices.push( vector2.x, vector2.y, vector2.z );
				vertices.push( vector3.x, vector3.y, vector3.z );
				vertices.push( vector4.x, vector4.y, vector4.z );

				//

				normal1.copy( point1 );
				normal1.applyQuaternion( quaternion );
				normal1.normalize();

				normal2.copy( point2 );
				normal2.applyQuaternion( quaternion );
				normal2.normalize();

				normal3.copy( point2 );
				normal3.applyQuaternion( quaternion );
				normal3.normalize();

				normal4.copy( point1 );
				normal4.applyQuaternion( quaternion );
				normal4.normalize();

				normals.push( normal1.x, normal1.y, normal1.z );
				normals.push( normal2.x, normal2.y, normal2.z );
				normals.push( normal4.x, normal4.y, normal4.z );

				normals.push( normal2.x, normal2.y, normal2.z );
				normals.push( normal3.x, normal3.y, normal3.z );
				normals.push( normal4.x, normal4.y, normal4.z );

			}

		}

		const fromPoint = new Vector3();
		const toPoint = new Vector3();

		for ( let i = 1; i <= divisions; i ++ ) {

			point.copy( curve.getPointAt( i / divisions ) );
			tangent.copy( curve.getTangentAt( i / divisions ) );

			const angle = Math.atan2( tangent.x, tangent.z );

			quaternion.setFromAxisAngle( up, angle );

			//

			if ( point.y > 10 ) {

				fromPoint.set( - 0.75, - 0.35, 0 );
				fromPoint.applyQuaternion( quaternion );
				fromPoint.add( point );

				toPoint.set( 0.75, - 0.35, 0 );
				toPoint.applyQuaternion( quaternion );
				toPoint.add( point );

				extrudeShape( tube1, fromPoint, toPoint );

				fromPoint.set( - 0.7, - 0.3, 0 );
				fromPoint.applyQuaternion( quaternion );
				fromPoint.add( point );

				toPoint.set( - 0.7, - point.y, 0 );
				toPoint.applyQuaternion( quaternion );
				toPoint.add( point );

				extrudeShape( tube2, fromPoint, toPoint );

				fromPoint.set( 0.7, - 0.3, 0 );
				fromPoint.applyQuaternion( quaternion );
				fromPoint.add( point );

				toPoint.set( 0.7, - point.y, 0 );
				toPoint.applyQuaternion( quaternion );
				toPoint.add( point );

				extrudeShape( tube3, fromPoint, toPoint );

			} else {

				fromPoint.set( 0, - 0.2, 0 );
				fromPoint.applyQuaternion( quaternion );
				fromPoint.add( point );

				toPoint.set( 0, - point.y, 0 );
				toPoint.applyQuaternion( quaternion );
				toPoint.add( point );

				extrudeShape( tube3, fromPoint, toPoint );

			}

		}

		this.setAttribute( 'position', new BufferAttribute( new Float32Array( vertices ), 3 ) );
		this.setAttribute( 'normal', new BufferAttribute( new Float32Array( normals ), 3 ) );

	}

}

/**
 * A procedural roller coaster shadow geometry.
 *
 * @augments BufferGeometry
 */
class RollerCoasterShadowGeometry extends BufferGeometry {

	/**
	 * Constructs a new geometry.
	 *
	 * @param {Curve} curve - The curve to generate the geometry along.
 	 * @param {number} divisions - The number of divisions which defines the detail of the geometry.
	 */
	constructor( curve, divisions ) {

		super();

		const vertices = [];

		const up = new Vector3( 0, 1, 0 );
		const forward = new Vector3();

		const quaternion = new Quaternion();
		const prevQuaternion = new Quaternion();
		prevQuaternion.setFromAxisAngle( up, Math.PI / 2 );

		const point = new Vector3();

		const prevPoint = new Vector3();
		prevPoint.copy( curve.getPointAt( 0 ) );
		prevPoint.y = 0;

		const vector1 = new Vector3();
		const vector2 = new Vector3();
		const vector3 = new Vector3();
		const vector4 = new Vector3();

		for ( let i = 1; i <= divisions; i ++ ) {

			point.copy( curve.getPointAt( i / divisions ) );
			point.y = 0;

			forward.subVectors( point, prevPoint );

			const angle = Math.atan2( forward.x, forward.z );

			quaternion.setFromAxisAngle( up, angle );

			vector1.set( - 0.3, 0, 0 );
			vector1.applyQuaternion( quaternion );
			vector1.add( point );

			vector2.set( 0.3, 0, 0 );
			vector2.applyQuaternion( quaternion );
			vector2.add( point );

			vector3.set( 0.3, 0, 0 );
			vector3.applyQuaternion( prevQuaternion );
			vector3.add( prevPoint );

			vector4.set( - 0.3, 0, 0 );
			vector4.applyQuaternion( prevQuaternion );
			vector4.add( prevPoint );

			vertices.push( vector1.x, vector1.y, vector1.z );
			vertices.push( vector2.x, vector2.y, vector2.z );
			vertices.push( vector4.x, vector4.y, vector4.z );

			vertices.push( vector2.x, vector2.y, vector2.z );
			vertices.push( vector3.x, vector3.y, vector3.z );
			vertices.push( vector4.x, vector4.y, vector4.z );

			prevPoint.copy( point );
			prevQuaternion.copy( quaternion );

		}

		this.setAttribute( 'position', new BufferAttribute( new Float32Array( vertices ), 3 ) );

	}

}

/**
 * A procedural sky geometry.
 *
 * @augments BufferGeometry
 */
class SkyGeometry extends BufferGeometry {

	/**
	 * Constructs a new geometry.
	 */
	constructor() {

		super();

		const vertices = [];

		for ( let i = 0; i < 100; i ++ ) {

			const x = Math.random() * 800 - 400;
			const y = Math.random() * 50 + 50;
			const z = Math.random() * 800 - 400;

			const size = Math.random() * 40 + 20;

			vertices.push( x - size, y, z - size );
			vertices.push( x + size, y, z - size );
			vertices.push( x - size, y, z + size );

			vertices.push( x + size, y, z - size );
			vertices.push( x + size, y, z + size );
			vertices.push( x - size, y, z + size );

		}


		this.setAttribute( 'position', new BufferAttribute( new Float32Array( vertices ), 3 ) );

	}

}

/**
 * A procedural trees geometry.
 *
 * @augments BufferGeometry
 */
class TreesGeometry extends BufferGeometry {

	/**
	 * Constructs a new geometry.
	 *
	 * @param {Mesh} landscape - A mesh representing the landscape. Trees will be positioned
	 * randomly on the landscape's surface.
	 */
	constructor( landscape ) {

		super();

		const vertices = [];
		const colors = [];

		const raycaster = new Raycaster();
		raycaster.ray.direction.set( 0, - 1, 0 );

		const _color = new Color();

		for ( let i = 0; i < 2000; i ++ ) {

			const x = Math.random() * 500 - 250;
			const z = Math.random() * 500 - 250;

			raycaster.ray.origin.set( x, 50, z );

			const intersections = raycaster.intersectObject( landscape );

			if ( intersections.length === 0 ) continue;

			const y = intersections[ 0 ].point.y;

			const height = Math.random() * 5 + 0.5;

			let angle = Math.random() * Math.PI * 2;

			vertices.push( x + Math.sin( angle ), y, z + Math.cos( angle ) );
			vertices.push( x, y + height, z );
			vertices.push( x + Math.sin( angle + Math.PI ), y, z + Math.cos( angle + Math.PI ) );

			angle += Math.PI / 2;

			vertices.push( x + Math.sin( angle ), y, z + Math.cos( angle ) );
			vertices.push( x, y + height, z );
			vertices.push( x + Math.sin( angle + Math.PI ), y, z + Math.cos( angle + Math.PI ) );

			const random = Math.random() * 0.1;

			for ( let j = 0; j < 6; j ++ ) {

				_color.setRGB( 0.2 + random, 0.4 + random, 0, SRGBColorSpace );

				colors.push( _color.r, _color.g, _color.b );

			}

		}

		this.setAttribute( 'position', new BufferAttribute( new Float32Array( vertices ), 3 ) );
		this.setAttribute( 'color', new BufferAttribute( new Float32Array( colors ), 3 ) );

	}

}

export { RollerCoasterGeometry, RollerCoasterLiftersGeometry, RollerCoasterShadowGeometry, SkyGeometry, TreesGeometry };