| /* |
| * 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 "SkPathOpsTriangle.h" |
| |
| // http://www.blackpawn.com/texts/pointinpoly/default.html |
| bool SkDTriangle::contains(const SkDPoint& pt) const { |
| // Compute vectors |
| SkDVector v0 = fPts[2] - fPts[0]; |
| SkDVector v1 = fPts[1] - fPts[0]; |
| SkDVector v2 = pt - fPts[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); |
| } |