cocos2d-html5
Version:
Cocos2d-HTML5 core package
150 lines (127 loc) • 5.52 kB
JavaScript
/****************************************************************************
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2009 Valentin Milea
http://www.cocos2d-x.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/
/**
* converts a line to a polygon
* @param {Float32Array} points
* @param {Number} stroke
* @param {Float32Array} vertices
* @param {Number} offset
* @param {Number} nuPoints
*/
cc.vertexLineToPolygon = function (points, stroke, vertices, offset, nuPoints) {
nuPoints += offset;
if (nuPoints <= 1)
return;
stroke *= 0.5;
var idx;
var nuPointsMinus = nuPoints - 1;
for (var i = offset; i < nuPoints; i++) {
idx = i * 2;
var p1 = cc.p(points[i * 2], points[i * 2 + 1]);
var perpVector;
if (i === 0)
perpVector = cc.pPerp(cc.pNormalize(cc.pSub(p1, cc.p(points[(i + 1) * 2], points[(i + 1) * 2 + 1]))));
else if (i === nuPointsMinus)
perpVector = cc.pPerp(cc.pNormalize(cc.pSub(cc.p(points[(i - 1) * 2], points[(i - 1) * 2 + 1]), p1)));
else {
var p0 = cc.p(points[(i - 1) * 2], points[(i - 1) * 2 + 1]);
var p2 = cc.p(points[(i + 1) * 2], points[(i + 1) * 2 + 1]);
var p2p1 = cc.pNormalize(cc.pSub(p2, p1));
var p0p1 = cc.pNormalize(cc.pSub(p0, p1));
// Calculate angle between vectors
var angle = Math.acos(cc.pDot(p2p1, p0p1));
if (angle < cc.DEGREES_TO_RADIANS(70))
perpVector = cc.pPerp(cc.pNormalize(cc.pMidpoint(p2p1, p0p1)));
else if (angle < cc.DEGREES_TO_RADIANS(170))
perpVector = cc.pNormalize(cc.pMidpoint(p2p1, p0p1));
else
perpVector = cc.pPerp(cc.pNormalize(cc.pSub(p2, p0)));
}
perpVector = cc.pMult(perpVector, stroke);
vertices[idx * 2] = p1.x + perpVector.x;
vertices[idx * 2 + 1] = p1.y + perpVector.y;
vertices[(idx + 1) * 2] = p1.x - perpVector.x;
vertices[(idx + 1) * 2 + 1] = p1.y - perpVector.y;
}
// Validate vertexes
offset = (offset == 0) ? 0 : offset - 1;
for (i = offset; i < nuPointsMinus; i++) {
idx = i * 2;
var idx1 = idx + 2;
var v1 = cc.Vertex2(vertices[idx * 2], vertices[idx * 2 + 1]);
var v2 = cc.Vertex2(vertices[(idx + 1) * 2], vertices[(idx + 1) * 2 + 1]);
var v3 = cc.Vertex2(vertices[idx1 * 2], vertices[idx1 * 2]);
var v4 = cc.Vertex2(vertices[(idx1 + 1) * 2], vertices[(idx1 + 1) * 2 + 1]);
//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);
var fixVertexResult = !cc.vertexLineIntersect(v1.x, v1.y, v4.x, v4.y, v2.x, v2.y, v3.x, v3.y);
if (!fixVertexResult.isSuccess)
if (fixVertexResult.value < 0.0 || fixVertexResult.value > 1.0)
fixVertexResult.isSuccess = true;
if (fixVertexResult.isSuccess) {
vertices[idx1 * 2] = v4.x;
vertices[idx1 * 2 + 1] = v4.y;
vertices[(idx1 + 1) * 2] = v3.x;
vertices[(idx1 + 1) * 2 + 1] = v3.y;
}
}
};
/**
* returns wheter or not the line intersects
* @param {Number} Ax
* @param {Number} Ay
* @param {Number} Bx
* @param {Number} By
* @param {Number} Cx
* @param {Number} Cy
* @param {Number} Dx
* @param {Number} Dy
* @return {Object}
*/
cc.vertexLineIntersect = function (Ax, Ay, Bx, By, Cx, Cy, Dx, Dy) {
var distAB, theCos, theSin, newX;
// FAIL: Line undefined
if ((Ax == Bx && Ay == By) || (Cx == Dx && Cy == Dy))
return {isSuccess:false, value:0};
// Translate system to make A the origin
Bx -= Ax;
By -= Ay;
Cx -= Ax;
Cy -= Ay;
Dx -= Ax;
Dy -= Ay;
// Length of segment AB
distAB = Math.sqrt(Bx * Bx + By * By);
// Rotate the system so that point B is on the positive X axis.
theCos = Bx / distAB;
theSin = By / distAB;
newX = Cx * theCos + Cy * theSin;
Cy = Cy * theCos - Cx * theSin;
Cx = newX;
newX = Dx * theCos + Dy * theSin;
Dy = Dy * theCos - Dx * theSin;
Dx = newX;
// FAIL: Lines are parallel.
if (Cy == Dy) return {isSuccess:false, value:0};
// Discover the relative position of the intersection in the line AB
var t = (Dx + (Cx - Dx) * Dy / (Dy - Cy)) / distAB;
// Success.
return {isSuccess:true, value:t};
};