1 /****************************************************************************
  2  Copyright (c) 2010-2012 cocos2d-x.org
  3  Copyright (c) 2009      Valentin Milea
  4 
  5  http://www.cocos2d-x.org
  6 
  7  Permission is hereby granted, free of charge, to any person obtaining a copy
  8  of this software and associated documentation files (the "Software"), to deal
  9  in the Software without restriction, including without limitation the rights
 10  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 11  copies of the Software, and to permit persons to whom the Software is
 12  furnished to do so, subject to the following conditions:
 13 
 14  The above copyright notice and this permission notice shall be included in
 15  all copies or substantial portions of the Software.
 16 
 17  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 18  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 19  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 20  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 21  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 22  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 23  THE SOFTWARE.
 24  ****************************************************************************/
 25 
 26 /**
 27  * converts a line to a polygon
 28  * @param {Float32Array} points
 29  * @param {Number} stroke
 30  * @param {Float32Array} vertices
 31  * @param {Number} offset
 32  * @param {Number} nuPoints
 33  */
 34 cc.vertexLineToPolygon = function (points, stroke, vertices, offset, nuPoints) {
 35     nuPoints += offset;
 36     if (nuPoints <= 1)
 37         return;
 38 
 39     stroke *= 0.5;
 40     var idx;
 41     var nuPointsMinus = nuPoints - 1;
 42     for (var i = offset; i < nuPoints; i++) {
 43         idx = i * 2;
 44         var p1 = cc.p(points[i * 2], points[i * 2 + 1]);
 45         var perpVector;
 46 
 47         if (i === 0)
 48             perpVector = cc.pPerp(cc.pNormalize(cc.pSub(p1, cc.p(points[(i + 1) * 2], points[(i + 1) * 2 + 1]))));
 49         else if (i === nuPointsMinus)
 50             perpVector = cc.pPerp(cc.pNormalize(cc.pSub(cc.p(points[(i - 1) * 2], points[(i - 1) * 2 + 1]), p1)));
 51         else {
 52             var p0 = cc.p(points[(i - 1) * 2], points[(i - 1) * 2 + 1]);
 53             var p2 = cc.p(points[(i + 1) * 2], points[(i + 1) * 2 + 1]);
 54 
 55             var p2p1 = cc.pNormalize(cc.pSub(p2, p1));
 56             var p0p1 = cc.pNormalize(cc.pSub(p0, p1));
 57 
 58             // Calculate angle between vectors
 59             var angle = Math.acos(cc.pDot(p2p1, p0p1));
 60 
 61             if (angle < cc.degreesToRadians(70))
 62                 perpVector = cc.pPerp(cc.pNormalize(cc.pMidpoint(p2p1, p0p1)));
 63             else if (angle < cc.degreesToRadians(170))
 64                 perpVector = cc.pNormalize(cc.pMidpoint(p2p1, p0p1));
 65             else
 66                 perpVector = cc.pPerp(cc.pNormalize(cc.pSub(p2, p0)));
 67         }
 68         perpVector = cc.pMult(perpVector, stroke);
 69 
 70         vertices[idx * 2] = p1.x + perpVector.x;
 71         vertices[idx * 2 + 1] = p1.y + perpVector.y;
 72         vertices[(idx + 1) * 2] = p1.x - perpVector.x;
 73         vertices[(idx + 1) * 2 + 1] = p1.y - perpVector.y;
 74     }
 75 
 76     // Validate vertexes
 77     offset = (offset == 0) ? 0 : offset - 1;
 78     for (i = offset; i < nuPointsMinus; i++) {
 79         idx = i * 2;
 80         var idx1 = idx + 2;
 81 
 82         var v1 = cc.vertex2(vertices[idx * 2], vertices[idx * 2 + 1]);
 83         var v2 = cc.vertex2(vertices[(idx + 1) * 2], vertices[(idx + 1) * 2 + 1]);
 84         var v3 = cc.vertex2(vertices[idx1 * 2], vertices[idx1 * 2]);
 85         var v4 = cc.vertex2(vertices[(idx1 + 1) * 2], vertices[(idx1 + 1) * 2 + 1]);
 86 
 87         //BOOL fixVertex = !ccpLineIntersect(ccp(p1.x, p1.y), ccp(p4.x, p4.y), ccp(p2.x, p2.y), ccp(p3.x, p3.y), &s, &t);
 88         var fixVertexResult = !cc.vertexLineIntersect(v1.x, v1.y, v4.x, v4.y, v2.x, v2.y, v3.x, v3.y);
 89         if (!fixVertexResult.isSuccess)
 90             if (fixVertexResult.value < 0.0 || fixVertexResult.value > 1.0)
 91                 fixVertexResult.isSuccess = true;
 92 
 93         if (fixVertexResult.isSuccess) {
 94             vertices[idx1 * 2] = v4.x;
 95             vertices[idx1 * 2 + 1] = v4.y;
 96             vertices[(idx1 + 1) * 2] = v3.x;
 97             vertices[(idx1 + 1) * 2 + 1] = v3.y;
 98         }
 99     }
100 };
101 
102 /**
103  * returns whether or not the line intersects
104  * @param {Number} Ax
105  * @param {Number} Ay
106  * @param {Number} Bx
107  * @param {Number} By
108  * @param {Number} Cx
109  * @param {Number} Cy
110  * @param {Number} Dx
111  * @param {Number} Dy
112  * @return {Object}
113  */
114 cc.vertexLineIntersect = function (Ax, Ay, Bx, By, Cx, Cy, Dx, Dy) {
115     var distAB, theCos, theSin, newX;
116 
117     // FAIL: Line undefined
118     if ((Ax == Bx && Ay == By) || (Cx == Dx && Cy == Dy))
119         return {isSuccess:false, value:0};
120 
121     //  Translate system to make A the origin
122     Bx -= Ax;
123     By -= Ay;
124     Cx -= Ax;
125     Cy -= Ay;
126     Dx -= Ax;
127     Dy -= Ay;
128 
129     // Length of segment AB
130     distAB = Math.sqrt(Bx * Bx + By * By);
131 
132     // Rotate the system so that point B is on the positive X axis.
133     theCos = Bx / distAB;
134     theSin = By / distAB;
135     newX = Cx * theCos + Cy * theSin;
136     Cy = Cy * theCos - Cx * theSin;
137     Cx = newX;
138     newX = Dx * theCos + Dy * theSin;
139     Dy = Dy * theCos - Dx * theSin;
140     Dx = newX;
141 
142     // FAIL: Lines are parallel.
143     if (Cy == Dy) return {isSuccess:false, value:0};
144 
145     // Discover the relative position of the intersection in the line AB
146     var t = (Dx + (Cx - Dx) * Dy / (Dy - Cy)) / distAB;
147 
148     // Success.
149     return {isSuccess:true, value:t};
150 };