three.js/src/extras/geometries/CylinderGeometry.js

/**
 * @author mr.doob / http://mrdoob.com/
 */

THREE.CylinderGeometry = function ( radiusTop, radiusBottom, height, segmentsRadius, segmentsHeight, openEnded ) {

	THREE.Geometry.call( this );

	radiusTop = radiusTop !== undefined ? radiusTop : 20;
	radiusBottom = radiusBottom !== undefined ? radiusBottom : 20;
	height = height !== undefined ? height : 100;

	var heightHalf = height / 2;
	var segmentsX = segmentsRadius || 8;
	var segmentsY = segmentsHeight || 1;

	var x, y, vertices = [], uvs = [];

	for ( y = 0; y <= segmentsY; y ++ ) {

		var verticesRow = [];
		var uvsRow = [];

		var v = y / segmentsY;
		var radius = v * ( radiusBottom - radiusTop ) + radiusTop;

		for ( x = 0; x <= segmentsX; x ++ ) {

			var u = x / segmentsX;

			var xpos = radius * Math.sin( u * Math.PI * 2 );
			var ypos = - v * height + heightHalf;
			var zpos = radius * Math.cos( u * Math.PI * 2 );

			this.vertices.push( new THREE.Vertex( xpos, ypos, zpos ) );

			verticesRow.push( this.vertices.length - 1 );
			uvsRow.push( new THREE.UV( u, v ) );

		}

		vertices.push( verticesRow );
		uvs.push( uvsRow );

	}

	for ( y = 0; y < segmentsY; y ++ ) {

		for ( x = 0; x < segmentsX; x ++ ) {

			var v1 = vertices[ y ][ x ];
			var v2 = vertices[ y + 1 ][ x ];
			var v3 = vertices[ y + 1 ][ x + 1 ];
			var v4 = vertices[ y ][ x + 1 ];

			// FIXME: These normals aren't right for cones.

			var n1 = this.vertices[ v1 ].clone().setY( 0 ).normalize();
			var n2 = this.vertices[ v2 ].clone().setY( 0 ).normalize();
			var n3 = this.vertices[ v3 ].clone().setY( 0 ).normalize();
			var n4 = this.vertices[ v4 ].clone().setY( 0 ).normalize();

			var uv1 = uvs[ y ][ x ].clone();
			var uv2 = uvs[ y + 1 ][ x ].clone();
			var uv3 = uvs[ y + 1 ][ x + 1 ].clone();
			var uv4 = uvs[ y ][ x + 1 ].clone();

			this.faces.push( new THREE.Face4( v1, v2, v3, v4, [ n1, n2, n3, n4 ] ) );
			this.faceVertexUvs[ 0 ].push( [ uv1, uv2, uv3, uv4 ] );

		}

	}

	// top cap

	if ( !openEnded && radiusTop > 0 ) {

		this.vertices.push( new THREE.Vertex( 0, heightHalf, 0 ) );

		for ( x = 0; x < segmentsX; x ++ ) {

			var v1 = vertices[ 0 ][ x ];
			var v2 = vertices[ 0 ][ x + 1 ];
			var v3 = this.vertices.length - 1;

			var n1 = new THREE.Vector3( 0, 1, 0 );
			var n2 = new THREE.Vector3( 0, 1, 0 );
			var n3 = new THREE.Vector3( 0, 1, 0 );

			var uv1 = uvs[ 0 ][ x ].clone();
			var uv2 = uvs[ 0 ][ x + 1 ].clone();
			var uv3 = new THREE.UV( uv2.u, 0 );

			this.faces.push( new THREE.Face3( v1, v2, v3, [ n1, n2, n3 ] ) );
			this.faceVertexUvs[ 0 ].push( [ uv1, uv2, uv3 ] );

		}

	}

	// bottom cap

	if ( !openEnded && radiusBottom > 0 ) {

		this.vertices.push( new THREE.Vertex( 0, - heightHalf, 0 ) );

		for ( x = 0; x < segmentsX; x ++ ) {

			var v1 = vertices[ y ][ x + 1 ];
			var v2 = vertices[ y ][ x ];
			var v3 = this.vertices.length - 1;

			var n1 = new THREE.Vector3( 0, - 1, 0 );
			var n2 = new THREE.Vector3( 0, - 1, 0 );
			var n3 = new THREE.Vector3( 0, - 1, 0 );

			var uv1 = uvs[ y ][ x + 1 ].clone();
			var uv2 = uvs[ y ][ x ].clone();
			var uv3 = new THREE.UV( uv2.u, 1 );

			this.faces.push( new THREE.Face3( v1, v2, v3, [ n1, n2, n3 ] ) );
			this.faceVertexUvs[ 0 ].push( [ uv1, uv2, uv3 ] );

		}

	}

	this.computeCentroids();
	this.computeFaceNormals();

}
THREE.CylinderGeometry.prototype = new THREE.Geometry();
THREE.CylinderGeometry.prototype.constructor = THREE.CylinderGeometry;