three.js/src/extras/FontUtils.js

/**
 * @author zz85 / http://www.lab4games.net/zz85/blog
 * @author alteredq / http://alteredqualia.com/
 *
 * For Text operations in three.js (See TextGeometry)
 *
 * It uses techniques used in:
 *
 * 	typeface.js and canvastext
 * 		For converting fonts and rendering with javascript
 *		http://typeface.neocracy.org
 *
 *	Triangulation ported from AS3
 *		Simple Polygon Triangulation
 *		http://actionsnippet.com/?p=1462
 *
 * 	A Method to triangulate shapes with holes
 *		http://www.sakri.net/blog/2009/06/12/an-approach-to-triangulating-polygons-with-holes/
 *
 */

THREE.FontUtils = {

	faces : {},

	// Just for now. face[weight][style]

	face : "helvetiker",
	weight: "normal",
	style : "normal",
	size : 150,
	divisions : 10,

	getFace : function() {

		return this.faces[ this.face ][ this.weight ][ this.style ];

	},

	loadFace : function( data ) {

		var family = data.familyName.toLowerCase();

		var ThreeFont = this;

		ThreeFont.faces[ family ] = ThreeFont.faces[ family ] || {};

		ThreeFont.faces[ family ][ data.cssFontWeight ] = ThreeFont.faces[ family ][ data.cssFontWeight ] || {};
		ThreeFont.faces[ family ][ data.cssFontWeight ][ data.cssFontStyle ] = data;

		var face = ThreeFont.faces[ family ][ data.cssFontWeight ][ data.cssFontStyle ] = data;

		return data;

	},

	drawText : function( text ) {

		var characterPts = [], allPts = [];

		// RenderText

		var i, p,
			face = this.getFace(),
			scale = this.size / face.resolution,
			offset = 0,
			chars = String( text ).split( '' ),
			length = chars.length;

		var fontPaths = [];

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

			var path = new THREE.Path();

			var ret = this.extractGlyphPoints( chars[ i ], face, scale, offset, path );
			offset += ret.offset;

			fontPaths.push( ret.path );

		}

		// get the width

		var width = offset / 2;
		//
		// for ( p = 0; p < allPts.length; p++ ) {
		//
		// 	allPts[ p ].x -= width;
		//
		// }

		//var extract = this.extractPoints( allPts, characterPts );
		//extract.contour = allPts;

		//extract.paths = fontPaths;
		//extract.offset = width;

		return { paths : fontPaths, offset : width };

	},




	extractGlyphPoints : function( c, face, scale, offset, path ) {

		var pts = [];

		var i, i2, divisions,
			outline, action, length,
			scaleX, scaleY,
			x, y, cpx, cpy, cpx0, cpy0, cpx1, cpy1, cpx2, cpy2,
			laste,
			glyph = face.glyphs[ c ] || face.glyphs[ '?' ];

		if ( !glyph ) return;

		if ( glyph.o ) {

			outline = glyph._cachedOutline || ( glyph._cachedOutline = glyph.o.split( ' ' ) );
			length = outline.length;

			scaleX = scale;
			scaleY = scale;

			for ( i = 0; i < length; ) {

				action = outline[ i ++ ];

				//console.log( action );

				switch( action ) {

				case 'm':

					// Move To

					x = outline[ i++ ] * scaleX + offset;
					y = outline[ i++ ] * scaleY;

					path.moveTo( x, y );
					break;

				case 'l':

					// Line To

					x = outline[ i++ ] * scaleX + offset;
					y = outline[ i++ ] * scaleY;
					path.lineTo(x,y);
					break;

				case 'q':

					// QuadraticCurveTo

					cpx  = outline[ i++ ] * scaleX + offset;
					cpy  = outline[ i++ ] * scaleY;
					cpx1 = outline[ i++ ] * scaleX + offset;
					cpy1 = outline[ i++ ] * scaleY;

					path.quadraticCurveTo(cpx1, cpy1, cpx, cpy);

					laste = pts[ pts.length - 1 ];

					if ( laste ) {

						cpx0 = laste.x;
						cpy0 = laste.y;

						for ( i2 = 1, divisions = this.divisions; i2 <= divisions; i2 ++ ) {

							var t = i2 / divisions;
							var tx = THREE.Shape.Utils.b2( t, cpx0, cpx1, cpx );
							var ty = THREE.Shape.Utils.b2( t, cpy0, cpy1, cpy );
					  }

				  }

				  break;

				case 'b':

					// Cubic Bezier Curve

					cpx  = outline[ i++ ] *  scaleX + offset;
					cpy  = outline[ i++ ] *  scaleY;
					cpx1 = outline[ i++ ] *  scaleX + offset;
					cpy1 = outline[ i++ ] * -scaleY;
					cpx2 = outline[ i++ ] *  scaleX + offset;
					cpy2 = outline[ i++ ] * -scaleY;

					path.bezierCurveTo( cpx, cpy, cpx1, cpy1, cpx2, cpy2 );

					laste = pts[ pts.length - 1 ];

					if ( laste ) {

						cpx0 = laste.x;
						cpy0 = laste.y;

						for ( i2 = 1, divisions = this.divisions; i2 <= divisions; i2 ++ ) {

							var t = i2 / divisions;
							var tx = THREE.Shape.Utils.b3( t, cpx0, cpx1, cpx2, cpx );
							var ty = THREE.Shape.Utils.b3( t, cpy0, cpy1, cpy2, cpy );

						}

					}

					break;

				}

			}
		}



		return { offset: glyph.ha*scale, path:path};
	}

};


THREE.FontUtils.generateShapes = function( text, parameters ) {

	// Parameters 

	parameters = parameters || {};

	var size = parameters.size !== undefined ? parameters.size : 100;
	var curveSegments = parameters.curveSegments !== undefined ? parameters.curveSegments: 4;

	var font = parameters.font !== undefined ? parameters.font : "helvetiker";
	var weight = parameters.weight !== undefined ? parameters.weight : "normal";
	var style = parameters.style !== undefined ? parameters.style : "normal";

	THREE.FontUtils.size = size;
	THREE.FontUtils.divisions = curveSegments;

	THREE.FontUtils.face = font;
	THREE.FontUtils.weight = weight;
	THREE.FontUtils.style = style;

	// Get a Font data json object

	var data = THREE.FontUtils.drawText( text );

	var paths = data.paths;
	var shapes = [];

	for ( var p = 0, pl = paths.length; p < pl; p ++ ) {

		Array.prototype.push.apply( shapes, paths[ p ].toShapes() );

	}

	return shapes;

};


/**
 * This code is a quick port of code written in C++ which was submitted to
 * flipcode.com by John W. Ratcliff  // July 22, 2000
 * See original code and more information here:
 * http://www.flipcode.com/archives/Efficient_Polygon_Triangulation.shtml
 *
 * ported to actionscript by Zevan Rosser
 * www.actionsnippet.com
 *
 * ported to javascript by Joshua Koo
 * http://www.lab4games.net/zz85/blog
 *
 */


( function( namespace ) {

	var EPSILON = 0.0000000001;

	// takes in an contour array and returns

	var process = function( contour, indices ) {

		var n = contour.length;

		if ( n < 3 ) return null;

		var result = [],
			verts = [],
			vertIndices = [];

		/* we want a counter-clockwise polygon in verts */

		var u, v, w;

		if ( area( contour ) > 0.0 ) {

			for ( v = 0; v < n; v++ ) verts[ v ] = v;

		} else {

			for ( v = 0; v < n; v++ ) verts[ v ] = ( n - 1 ) - v;

		}

		var nv = n;

		/*  remove nv - 2 vertices, creating 1 triangle every time */

		var count = 2 * nv;   /* error detection */

		for( v = nv - 1; nv > 2; ) {

			/* if we loop, it is probably a non-simple polygon */

			if ( ( count-- ) <= 0 ) {

				//** Triangulate: ERROR - probable bad polygon!

				//throw ( "Warning, unable to triangulate polygon!" );
				//return null;
				// Sometimes warning is fine, especially polygons are triangulated in reverse.
				console.log( "Warning, unable to triangulate polygon!" );

				if ( indices ) return vertIndices;
				return result;

			}

			/* three consecutive vertices in current polygon, <u,v,w> */

			u = v; 	 	if ( nv <= u ) u = 0;     /* previous */
			v = u + 1;  if ( nv <= v ) v = 0;     /* new v    */
			w = v + 1;  if ( nv <= w ) w = 0;     /* next     */

			if ( snip( contour, u, v, w, nv, verts ) ) {

				var a, b, c, s, t;

				/* true names of the vertices */

				a = verts[ u ];
				b = verts[ v ];
				c = verts[ w ];

				/* output Triangle */

				/*
				result.push( contour[ a ] );
				result.push( contour[ b ] );
				result.push( contour[ c ] );
				*/
				result.push( [ contour[ a ],
					contour[ b ],
					contour[ c ] ] );


				vertIndices.push( [ verts[ u ], verts[ v ], verts[ w ] ] );

				/* remove v from the remaining polygon */

				for( s = v, t = v + 1; t < nv; s++, t++ ) {

					verts[ s ] = verts[ t ];

				}

				nv--;

				/* reset error detection counter */

				count = 2 * nv;

			}

		}

		if ( indices ) return vertIndices;
		return result;

	};

	// calculate area of the contour polygon

	var area = function ( contour ) {

		var n = contour.length;
		var a = 0.0;

		for( var p = n - 1, q = 0; q < n; p = q++ ) {

			a += contour[ p ].x * contour[ q ].y - contour[ q ].x * contour[ p ].y;

		}

		return a * 0.5;

	};

	// see if p is inside triangle abc

	var insideTriangle = function( ax, ay,
								   bx, by,
								   cx, cy,
								   px, py ) {

		  var aX, aY, bX, bY;
		  var cX, cY, apx, apy;
		  var bpx, bpy, cpx, cpy;
		  var cCROSSap, bCROSScp, aCROSSbp;

		  aX = cx - bx;  aY = cy - by;
		  bX = ax - cx;  bY = ay - cy;
		  cX = bx - ax;  cY = by - ay;
		  apx= px  -ax;  apy= py - ay;
		  bpx= px - bx;  bpy= py - by;
		  cpx= px - cx;  cpy= py - cy;

		  aCROSSbp = aX*bpy - aY*bpx;
		  cCROSSap = cX*apy - cY*apx;
		  bCROSScp = bX*cpy - bY*cpx;

		  return ( (aCROSSbp >= 0.0) && (bCROSScp >= 0.0) && (cCROSSap >= 0.0) );

	};


	var snip = function ( contour, u, v, w, n, verts ) {

		var p;
		var ax, ay, bx, by;
		var cx, cy, px, py;

		ax = contour[ verts[ u ] ].x;
		ay = contour[ verts[ u ] ].y;

		bx = contour[ verts[ v ] ].x;
		by = contour[ verts[ v ] ].y;

		cx = contour[ verts[ w ] ].x;
		cy = contour[ verts[ w ] ].y;

		if ( EPSILON > (((bx-ax)*(cy-ay)) - ((by-ay)*(cx-ax))) ) return false;

			for ( p = 0; p < n; p++ ) {

				if( (p == u) || (p == v) || (p == w) ) continue;

				px = contour[ verts[ p ] ].x
				py = contour[ verts[ p ] ].y

				if ( insideTriangle( ax, ay, bx, by, cx, cy, px, py ) ) return false;

		  }

		  return true;

	};


	namespace.Triangulate = process;
	namespace.Triangulate.area = area;

	return namespace;

})(THREE.FontUtils);

// To use the typeface.js face files, hook up the API
self._typeface_js = { faces: THREE.FontUtils.faces, loadFace: THREE.FontUtils.loadFace };