| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "TriangleUtilities.h" |
| |
| // http://www.blackpawn.com/texts/pointinpoly/default.html |
| bool pointInTriangle(const Triangle& triangle, const _Point& pt) { |
| // Compute vectors |
| _Vector v0 = triangle[2] - triangle[0]; |
| _Vector v1 = triangle[1] - triangle[0]; |
| _Vector v2 = pt - triangle[0]; |
| |
| // Compute dot products |
| double dot00 = v0.dot(v0); |
| double dot01 = v0.dot(v1); |
| double dot02 = v0.dot(v2); |
| double dot11 = v1.dot(v1); |
| double dot12 = v1.dot(v2); |
| |
| // Compute barycentric coordinates |
| double invDenom = 1 / (dot00 * dot11 - dot01 * dot01); |
| double u = (dot11 * dot02 - dot01 * dot12) * invDenom; |
| double v = (dot00 * dot12 - dot01 * dot02) * invDenom; |
| |
| // Check if point is in triangle |
| return (u >= 0) && (v >= 0) && (u + v < 1); |
| } |