mirror of
https://github.com/photonstorm/phaser
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149 lines
3.4 KiB
JavaScript
149 lines
3.4 KiB
JavaScript
/*
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PolyK library
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url: http://polyk.ivank.net
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Released under MIT licence.
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Copyright (c) 2012 Ivan Kuckir
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Permission is hereby granted, free of charge, to any person
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obtaining a copy of this software and associated documentation
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files (the "Software"), to deal in the Software without
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restriction, including without limitation the rights to use,
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copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following
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conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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OTHER DEALINGS IN THE SOFTWARE.
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This is an amazing lib!
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slightly modified by mat groves (matgroves.com);
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*/
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PIXI.PolyK = {};
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/**
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* Triangulates shapes for webGL graphic fills
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*
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* @method Triangulate
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* @namespace PolyK
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* @constructor
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*/
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PIXI.PolyK.Triangulate = function(p)
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{
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var sign = true;
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var n = p.length>>1;
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if(n<3) return [];
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var tgs = [];
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var avl = [];
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for(var i=0; i<n; i++) avl.push(i);
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var i = 0;
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var al = n;
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while(al > 3)
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{
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var i0 = avl[(i+0)%al];
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var i1 = avl[(i+1)%al];
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var i2 = avl[(i+2)%al];
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var ax = p[2*i0], ay = p[2*i0+1];
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var bx = p[2*i1], by = p[2*i1+1];
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var cx = p[2*i2], cy = p[2*i2+1];
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var earFound = false;
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if(PIXI.PolyK._convex(ax, ay, bx, by, cx, cy, sign))
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{
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earFound = true;
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for(var j=0; j<al; j++)
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{
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var vi = avl[j];
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if(vi==i0 || vi==i1 || vi==i2) continue;
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if(PIXI.PolyK._PointInTriangle(p[2*vi], p[2*vi+1], ax, ay, bx, by, cx, cy)) {earFound = false; break;}
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}
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}
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if(earFound)
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{
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tgs.push(i0, i1, i2);
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avl.splice((i+1)%al, 1);
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al--;
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i = 0;
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}
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else if(i++ > 3*al)
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{
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// need to flip flip reverse it!
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// reset!
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if(sign)
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{
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var tgs = [];
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avl = [];
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for(var i=0; i<n; i++) avl.push(i);
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i = 0;
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al = n;
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sign = false;
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}
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else
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{
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console.log("PIXI Warning: shape too complex to fill")
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return [];
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}
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}
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}
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tgs.push(avl[0], avl[1], avl[2]);
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return tgs;
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}
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/**
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* Checks if a point is within a triangle
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*
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* @class _PointInTriangle
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* @namespace PolyK
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* @private
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*/
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PIXI.PolyK._PointInTriangle = function(px, py, ax, ay, bx, by, cx, cy)
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{
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var v0x = cx-ax;
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var v0y = cy-ay;
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var v1x = bx-ax;
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var v1y = by-ay;
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var v2x = px-ax;
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var v2y = py-ay;
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var dot00 = v0x*v0x+v0y*v0y;
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var dot01 = v0x*v1x+v0y*v1y;
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var dot02 = v0x*v2x+v0y*v2y;
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var dot11 = v1x*v1x+v1y*v1y;
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var dot12 = v1x*v2x+v1y*v2y;
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var invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
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var u = (dot11 * dot02 - dot01 * dot12) * invDenom;
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var v = (dot00 * dot12 - dot01 * dot02) * invDenom;
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// Check if point is in triangle
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return (u >= 0) && (v >= 0) && (u + v < 1);
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}
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/**
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* Checks if a shape is convex
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*
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* @class _convex
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* @namespace PolyK
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* @private
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*/
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PIXI.PolyK._convex = function(ax, ay, bx, by, cx, cy, sign)
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{
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return ((ay-by)*(cx-bx) + (bx-ax)*(cy-by) >= 0) == sign;
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}
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