| /* |
| * Poly2Tri Copyright (c) 2009-2010, Poly2Tri Contributors |
| * http://code.google.com/p/poly2tri/ |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without modification, |
| * are permitted provided that the following conditions are met: |
| * |
| * * Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * * Neither the name of Poly2Tri nor the names of its contributors may be |
| * used to endorse or promote products derived from this software without specific |
| * prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifndef UTILS_H |
| #define UTILS_H |
| |
| // Otherwise #defines like M_PI are undeclared under Visual Studio |
| #define _USE_MATH_DEFINES |
| |
| #include <exception> |
| #include <math.h> |
| |
| // C99 removes M_PI from math.h |
| #ifndef M_PI |
| #define M_PI 3.14159265358979323846264338327 |
| #endif |
| |
| namespace p2t { |
| |
| const double PI_3div4 = 3 * M_PI / 4; |
| const double PI_div2 = 1.57079632679489661923; |
| const double EPSILON = 1e-12; |
| |
| enum Orientation { CW, CCW, COLLINEAR }; |
| |
| /** |
| * Forumla to calculate signed area<br> |
| * Positive if CCW<br> |
| * Negative if CW<br> |
| * 0 if collinear<br> |
| * <pre> |
| * A[P1,P2,P3] = (x1*y2 - y1*x2) + (x2*y3 - y2*x3) + (x3*y1 - y3*x1) |
| * = (x1-x3)*(y2-y3) - (y1-y3)*(x2-x3) |
| * </pre> |
| */ |
| Orientation Orient2d(const Point& pa, const Point& pb, const Point& pc) |
| { |
| double detleft = (pa.x - pc.x) * (pb.y - pc.y); |
| double detright = (pa.y - pc.y) * (pb.x - pc.x); |
| double val = detleft - detright; |
| if (val > -EPSILON && val < EPSILON) { |
| return COLLINEAR; |
| } else if (val > 0) { |
| return CCW; |
| } |
| return CW; |
| } |
| |
| /* |
| bool InScanArea(Point& pa, Point& pb, Point& pc, Point& pd) |
| { |
| double pdx = pd.x; |
| double pdy = pd.y; |
| double adx = pa.x - pdx; |
| double ady = pa.y - pdy; |
| double bdx = pb.x - pdx; |
| double bdy = pb.y - pdy; |
| |
| double adxbdy = adx * bdy; |
| double bdxady = bdx * ady; |
| double oabd = adxbdy - bdxady; |
| |
| if (oabd <= EPSILON) { |
| return false; |
| } |
| |
| double cdx = pc.x - pdx; |
| double cdy = pc.y - pdy; |
| |
| double cdxady = cdx * ady; |
| double adxcdy = adx * cdy; |
| double ocad = cdxady - adxcdy; |
| |
| if (ocad <= EPSILON) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| */ |
| |
| bool InScanArea(const Point& pa, const Point& pb, const Point& pc, const Point& pd) |
| { |
| double oadb = (pa.x - pb.x)*(pd.y - pb.y) - (pd.x - pb.x)*(pa.y - pb.y); |
| if (oadb >= -EPSILON) { |
| return false; |
| } |
| |
| double oadc = (pa.x - pc.x)*(pd.y - pc.y) - (pd.x - pc.x)*(pa.y - pc.y); |
| if (oadc <= EPSILON) { |
| return false; |
| } |
| return true; |
| } |
| |
| } |
| |
| #endif |