three.js/src/geometries/ExtrudeGeometry.js

/**
 * @author zz85 / http://www.lab4games.net/zz85/blog
 *
 * Creates extruded geometry from a path shape.
 *
 * parameters = {
 *
 *  curveSegments: <int>, // number of points on the curves
 *  steps: <int>, // number of points for z-side extrusions / used for subdividing segments of extrude spline too
 *  amount: <float>, // Depth to extrude the shape
 *
 *  bevelEnabled: <bool>, // turn on bevel
 *  bevelThickness: <float>, // how deep into the original shape bevel goes
 *  bevelSize: <float>, // how far from shape outline is bevel
 *  bevelSegments: <int>, // number of bevel layers
 *
 *  extrudePath: <THREE.Curve> // curve to extrude shape along
 *
 *  UVGenerator: <Object> // object that provides UV generator functions
 *
 * }
 */

import { Geometry } from '../core/Geometry.js';
import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import { Vector2 } from '../math/Vector2.js';
import { Vector3 } from '../math/Vector3.js';
import { ShapeUtils } from '../extras/ShapeUtils.js';

// ExtrudeGeometry

function ExtrudeGeometry( shapes, options ) {

	Geometry.call( this );

	this.type = 'ExtrudeGeometry';

	this.parameters = {
		shapes: shapes,
		options: options
	};

	this.fromBufferGeometry( new ExtrudeBufferGeometry( shapes, options ) );
	this.mergeVertices();

}

ExtrudeGeometry.prototype = Object.create( Geometry.prototype );
ExtrudeGeometry.prototype.constructor = ExtrudeGeometry;

// ExtrudeBufferGeometry

function ExtrudeBufferGeometry( shapes, options ) {

	BufferGeometry.call( this );

	this.type = 'ExtrudeBufferGeometry';

	this.parameters = {
		shapes: shapes,
		options: options
	};

	shapes = Array.isArray( shapes ) ? shapes : [ shapes ];

	var scope = this;

	var verticesArray = [];
	var uvArray = [];

	for ( var i = 0, l = shapes.length; i < l; i ++ ) {

		var shape = shapes[ i ];
		addShape( shape, options );

	}

	// build geometry

	this.addAttribute( 'position', new Float32BufferAttribute( verticesArray, 3 ) );
	this.addAttribute( 'uv', new Float32BufferAttribute( uvArray, 2 ) );

	this.computeVertexNormals();

	// functions

	function addShape( shape ) {

		var placeholder = [];

		// options

		var curveSegments = options.curveSegments !== undefined ? options.curveSegments : 12;
		var steps = options.steps !== undefined ? options.steps : 1;
		var amount = options.amount !== undefined ? options.amount : 100;

		var bevelEnabled = options.bevelEnabled !== undefined ? options.bevelEnabled : true;
		var bevelThickness = options.bevelThickness !== undefined ? options.bevelThickness : 6;
		var bevelSize = options.bevelSize !== undefined ? options.bevelSize : bevelThickness - 2;
		var bevelSegments = options.bevelSegments !== undefined ? options.bevelSegments : 3;

		var extrudePath = options.extrudePath;

		var uvgen = options.UVGenerator !== undefined ? options.UVGenerator : WorldUVGenerator;

		//

		var extrudePts, extrudeByPath = false;
		var splineTube, binormal, normal, position2;

		if ( extrudePath ) {

			extrudePts = extrudePath.getSpacedPoints( steps );

			extrudeByPath = true;
			bevelEnabled = false; // bevels not supported for path extrusion

			// SETUP TNB variables

			// TODO1 - have a .isClosed in spline?

			splineTube = extrudePath.computeFrenetFrames( steps, false );

			// console.log(splineTube, 'splineTube', splineTube.normals.length, 'steps', steps, 'extrudePts', extrudePts.length);

			binormal = new Vector3();
			normal = new Vector3();
			position2 = new Vector3();

		}

		// Safeguards if bevels are not enabled

		if ( ! bevelEnabled ) {

			bevelSegments = 0;
			bevelThickness = 0;
			bevelSize = 0;

		}

		// Variables initialization

		var ahole, h, hl; // looping of holes

		var shapePoints = shape.extractPoints( curveSegments );

		var vertices = shapePoints.shape;
		var holes = shapePoints.holes;

		var reverse = ! ShapeUtils.isClockWise( vertices );

		if ( reverse ) {

			vertices = vertices.reverse();

			// Maybe we should also check if holes are in the opposite direction, just to be safe ...

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];

				if ( ShapeUtils.isClockWise( ahole ) ) {

					holes[ h ] = ahole.reverse();

				}

			}

		}


		var faces = ShapeUtils.triangulateShape( vertices, holes );

		/* Vertices */

		var contour = vertices; // vertices has all points but contour has only points of circumference

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];

			vertices = vertices.concat( ahole );

		}


		function scalePt2( pt, vec, size ) {

			if ( ! vec ) console.error( "THREE.ExtrudeGeometry: vec does not exist" );

			return vec.clone().multiplyScalar( size ).add( pt );

		}

		var b, bs, t, z,
			vert, vlen = vertices.length,
			face, flen = faces.length;


		// Find directions for point movement


		function getBevelVec( inPt, inPrev, inNext ) {

			// computes for inPt the corresponding point inPt' on a new contour
			//   shifted by 1 unit (length of normalized vector) to the left
			// if we walk along contour clockwise, this new contour is outside the old one
			//
			// inPt' is the intersection of the two lines parallel to the two
			//  adjacent edges of inPt at a distance of 1 unit on the left side.

			var v_trans_x, v_trans_y, shrink_by; // resulting translation vector for inPt

			// good reading for geometry algorithms (here: line-line intersection)
			// http://geomalgorithms.com/a05-_intersect-1.html

			var v_prev_x = inPt.x - inPrev.x,
				v_prev_y = inPt.y - inPrev.y;
			var v_next_x = inNext.x - inPt.x,
				v_next_y = inNext.y - inPt.y;

			var v_prev_lensq = ( v_prev_x * v_prev_x + v_prev_y * v_prev_y );

			// check for collinear edges
			var collinear0 = ( v_prev_x * v_next_y - v_prev_y * v_next_x );

			if ( Math.abs( collinear0 ) > Number.EPSILON ) {

				// not collinear

				// length of vectors for normalizing

				var v_prev_len = Math.sqrt( v_prev_lensq );
				var v_next_len = Math.sqrt( v_next_x * v_next_x + v_next_y * v_next_y );

				// shift adjacent points by unit vectors to the left

				var ptPrevShift_x = ( inPrev.x - v_prev_y / v_prev_len );
				var ptPrevShift_y = ( inPrev.y + v_prev_x / v_prev_len );

				var ptNextShift_x = ( inNext.x - v_next_y / v_next_len );
				var ptNextShift_y = ( inNext.y + v_next_x / v_next_len );

				// scaling factor for v_prev to intersection point

				var sf = ( ( ptNextShift_x - ptPrevShift_x ) * v_next_y -
						( ptNextShift_y - ptPrevShift_y ) * v_next_x ) /
					( v_prev_x * v_next_y - v_prev_y * v_next_x );

				// vector from inPt to intersection point

				v_trans_x = ( ptPrevShift_x + v_prev_x * sf - inPt.x );
				v_trans_y = ( ptPrevShift_y + v_prev_y * sf - inPt.y );

				// Don't normalize!, otherwise sharp corners become ugly
				//  but prevent crazy spikes
				var v_trans_lensq = ( v_trans_x * v_trans_x + v_trans_y * v_trans_y );
				if ( v_trans_lensq <= 2 ) {

					return new Vector2( v_trans_x, v_trans_y );

				} else {

					shrink_by = Math.sqrt( v_trans_lensq / 2 );

				}

			} else {

				// handle special case of collinear edges

				var direction_eq = false; // assumes: opposite
				if ( v_prev_x > Number.EPSILON ) {

					if ( v_next_x > Number.EPSILON ) {

						direction_eq = true;

					}

				} else {

					if ( v_prev_x < - Number.EPSILON ) {

						if ( v_next_x < - Number.EPSILON ) {

							direction_eq = true;

						}

					} else {

						if ( Math.sign( v_prev_y ) === Math.sign( v_next_y ) ) {

							direction_eq = true;

						}

					}

				}

				if ( direction_eq ) {

					// console.log("Warning: lines are a straight sequence");
					v_trans_x = - v_prev_y;
					v_trans_y = v_prev_x;
					shrink_by = Math.sqrt( v_prev_lensq );

				} else {

					// console.log("Warning: lines are a straight spike");
					v_trans_x = v_prev_x;
					v_trans_y = v_prev_y;
					shrink_by = Math.sqrt( v_prev_lensq / 2 );

				}

			}

			return new Vector2( v_trans_x / shrink_by, v_trans_y / shrink_by );

		}


		var contourMovements = [];

		for ( var i = 0, il = contour.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

			if ( j === il ) j = 0;
			if ( k === il ) k = 0;

			//  (j)---(i)---(k)
			// console.log('i,j,k', i, j , k)

			contourMovements[ i ] = getBevelVec( contour[ i ], contour[ j ], contour[ k ] );

		}

		var holesMovements = [],
			oneHoleMovements, verticesMovements = contourMovements.concat();

		for ( h = 0, hl = holes.length; h < hl; h ++ ) {

			ahole = holes[ h ];

			oneHoleMovements = [];

			for ( i = 0, il = ahole.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

				if ( j === il ) j = 0;
				if ( k === il ) k = 0;

				//  (j)---(i)---(k)
				oneHoleMovements[ i ] = getBevelVec( ahole[ i ], ahole[ j ], ahole[ k ] );

			}

			holesMovements.push( oneHoleMovements );
			verticesMovements = verticesMovements.concat( oneHoleMovements );

		}


		// Loop bevelSegments, 1 for the front, 1 for the back

		for ( b = 0; b < bevelSegments; b ++ ) {

			//for ( b = bevelSegments; b > 0; b -- ) {

			t = b / bevelSegments;
			z = bevelThickness * Math.cos( t * Math.PI / 2 );
			bs = bevelSize * Math.sin( t * Math.PI / 2 );

			// contract shape

			for ( i = 0, il = contour.length; i < il; i ++ ) {

				vert = scalePt2( contour[ i ], contourMovements[ i ], bs );

				v( vert.x, vert.y, - z );

			}

			// expand holes

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];
				oneHoleMovements = holesMovements[ h ];

				for ( i = 0, il = ahole.length; i < il; i ++ ) {

					vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

					v( vert.x, vert.y, - z );

				}

			}

		}

		bs = bevelSize;

		// Back facing vertices

		for ( i = 0; i < vlen; i ++ ) {

			vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

			if ( ! extrudeByPath ) {

				v( vert.x, vert.y, 0 );

			} else {

				// v( vert.x, vert.y + extrudePts[ 0 ].y, extrudePts[ 0 ].x );

				normal.copy( splineTube.normals[ 0 ] ).multiplyScalar( vert.x );
				binormal.copy( splineTube.binormals[ 0 ] ).multiplyScalar( vert.y );

				position2.copy( extrudePts[ 0 ] ).add( normal ).add( binormal );

				v( position2.x, position2.y, position2.z );

			}

		}

		// Add stepped vertices...
		// Including front facing vertices

		var s;

		for ( s = 1; s <= steps; s ++ ) {

			for ( i = 0; i < vlen; i ++ ) {

				vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

				if ( ! extrudeByPath ) {

					v( vert.x, vert.y, amount / steps * s );

				} else {

					// v( vert.x, vert.y + extrudePts[ s - 1 ].y, extrudePts[ s - 1 ].x );

					normal.copy( splineTube.normals[ s ] ).multiplyScalar( vert.x );
					binormal.copy( splineTube.binormals[ s ] ).multiplyScalar( vert.y );

					position2.copy( extrudePts[ s ] ).add( normal ).add( binormal );

					v( position2.x, position2.y, position2.z );

				}

			}

		}


		// Add bevel segments planes

		//for ( b = 1; b <= bevelSegments; b ++ ) {
		for ( b = bevelSegments - 1; b >= 0; b -- ) {

			t = b / bevelSegments;
			z = bevelThickness * Math.cos( t * Math.PI / 2 );
			bs = bevelSize * Math.sin( t * Math.PI / 2 );

			// contract shape

			for ( i = 0, il = contour.length; i < il; i ++ ) {

				vert = scalePt2( contour[ i ], contourMovements[ i ], bs );
				v( vert.x, vert.y, amount + z );

			}

			// expand holes

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];
				oneHoleMovements = holesMovements[ h ];

				for ( i = 0, il = ahole.length; i < il; i ++ ) {

					vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

					if ( ! extrudeByPath ) {

						v( vert.x, vert.y, amount + z );

					} else {

						v( vert.x, vert.y + extrudePts[ steps - 1 ].y, extrudePts[ steps - 1 ].x + z );

					}

				}

			}

		}

		/* Faces */

		// Top and bottom faces

		buildLidFaces();

		// Sides faces

		buildSideFaces();


		/////  Internal functions

		function buildLidFaces() {

			var start = verticesArray.length / 3;

			if ( bevelEnabled ) {

				var layer = 0; // steps + 1
				var offset = vlen * layer;

				// Bottom faces

				for ( i = 0; i < flen; i ++ ) {

					face = faces[ i ];
					f3( face[ 2 ] + offset, face[ 1 ] + offset, face[ 0 ] + offset );

				}

				layer = steps + bevelSegments * 2;
				offset = vlen * layer;

				// Top faces

				for ( i = 0; i < flen; i ++ ) {

					face = faces[ i ];
					f3( face[ 0 ] + offset, face[ 1 ] + offset, face[ 2 ] + offset );

				}

			} else {

				// Bottom faces

				for ( i = 0; i < flen; i ++ ) {

					face = faces[ i ];
					f3( face[ 2 ], face[ 1 ], face[ 0 ] );

				}

				// Top faces

				for ( i = 0; i < flen; i ++ ) {

					face = faces[ i ];
					f3( face[ 0 ] + vlen * steps, face[ 1 ] + vlen * steps, face[ 2 ] + vlen * steps );

				}

			}

			scope.addGroup( start, verticesArray.length / 3 - start, 0 );

		}

		// Create faces for the z-sides of the shape

		function buildSideFaces() {

			var start = verticesArray.length / 3;
			var layeroffset = 0;
			sidewalls( contour, layeroffset );
			layeroffset += contour.length;

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];
				sidewalls( ahole, layeroffset );

				//, true
				layeroffset += ahole.length;

			}


			scope.addGroup( start, verticesArray.length / 3 - start, 1 );


		}

		function sidewalls( contour, layeroffset ) {

			var j, k;
			i = contour.length;

			while ( -- i >= 0 ) {

				j = i;
				k = i - 1;
				if ( k < 0 ) k = contour.length - 1;

				//console.log('b', i,j, i-1, k,vertices.length);

				var s = 0,
					sl = steps + bevelSegments * 2;

				for ( s = 0; s < sl; s ++ ) {

					var slen1 = vlen * s;
					var slen2 = vlen * ( s + 1 );

					var a = layeroffset + j + slen1,
						b = layeroffset + k + slen1,
						c = layeroffset + k + slen2,
						d = layeroffset + j + slen2;

					f4( a, b, c, d );

				}

			}

		}

		function v( x, y, z ) {

			placeholder.push( x );
			placeholder.push( y );
			placeholder.push( z );

		}


		function f3( a, b, c ) {

			addVertex( a );
			addVertex( b );
			addVertex( c );

			var nextIndex = verticesArray.length / 3;
			var uvs = uvgen.generateTopUV( scope, verticesArray, nextIndex - 3, nextIndex - 2, nextIndex - 1 );

			addUV( uvs[ 0 ] );
			addUV( uvs[ 1 ] );
			addUV( uvs[ 2 ] );

		}

		function f4( a, b, c, d ) {

			addVertex( a );
			addVertex( b );
			addVertex( d );

			addVertex( b );
			addVertex( c );
			addVertex( d );


			var nextIndex = verticesArray.length / 3;
			var uvs = uvgen.generateSideWallUV( scope, verticesArray, nextIndex - 6, nextIndex - 3, nextIndex - 2, nextIndex - 1 );

			addUV( uvs[ 0 ] );
			addUV( uvs[ 1 ] );
			addUV( uvs[ 3 ] );

			addUV( uvs[ 1 ] );
			addUV( uvs[ 2 ] );
			addUV( uvs[ 3 ] );

		}

		function addVertex( index ) {

			verticesArray.push( placeholder[ index * 3 + 0 ] );
			verticesArray.push( placeholder[ index * 3 + 1 ] );
			verticesArray.push( placeholder[ index * 3 + 2 ] );

		}


		function addUV( vector2 ) {

			uvArray.push( vector2.x );
			uvArray.push( vector2.y );

		}

	}

}

ExtrudeBufferGeometry.prototype = Object.create( BufferGeometry.prototype );
ExtrudeBufferGeometry.prototype.constructor = ExtrudeBufferGeometry;

var WorldUVGenerator = {

	generateTopUV: function ( geometry, vertices, indexA, indexB, indexC ) {

		var a_x = vertices[ indexA * 3 ];
		var a_y = vertices[ indexA * 3 + 1 ];
		var b_x = vertices[ indexB * 3 ];
		var b_y = vertices[ indexB * 3 + 1 ];
		var c_x = vertices[ indexC * 3 ];
		var c_y = vertices[ indexC * 3 + 1 ];

		return [
			new Vector2( a_x, a_y ),
			new Vector2( b_x, b_y ),
			new Vector2( c_x, c_y )
		];

	},

	generateSideWallUV: function ( geometry, vertices, indexA, indexB, indexC, indexD ) {

		var a_x = vertices[ indexA * 3 ];
		var a_y = vertices[ indexA * 3 + 1 ];
		var a_z = vertices[ indexA * 3 + 2 ];
		var b_x = vertices[ indexB * 3 ];
		var b_y = vertices[ indexB * 3 + 1 ];
		var b_z = vertices[ indexB * 3 + 2 ];
		var c_x = vertices[ indexC * 3 ];
		var c_y = vertices[ indexC * 3 + 1 ];
		var c_z = vertices[ indexC * 3 + 2 ];
		var d_x = vertices[ indexD * 3 ];
		var d_y = vertices[ indexD * 3 + 1 ];
		var d_z = vertices[ indexD * 3 + 2 ];

		if ( Math.abs( a_y - b_y ) < 0.01 ) {

			return [
				new Vector2( a_x, 1 - a_z ),
				new Vector2( b_x, 1 - b_z ),
				new Vector2( c_x, 1 - c_z ),
				new Vector2( d_x, 1 - d_z )
			];

		} else {

			return [
				new Vector2( a_y, 1 - a_z ),
				new Vector2( b_y, 1 - b_z ),
				new Vector2( c_y, 1 - c_z ),
				new Vector2( d_y, 1 - d_z )
			];

		}

	}
};


export { ExtrudeGeometry, ExtrudeBufferGeometry };