The Tor Browser / file comparison
comparison: gfx/skia/trunk/src/pathops/SkPathOpsTriangle.cpp
gfx/skia/trunk/src/pathops/SkPathOpsTriangle.cpp
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:12510068ad8c |
|---|---|
| 1 /* | |
| 2 * Copyright 2012 Google Inc. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license that can be | |
| 5 * found in the LICENSE file. | |
| 6 */ | |
| 7 | |
| 8 #include "SkPathOpsTriangle.h" | |
| 9 | |
| 10 // http://www.blackpawn.com/texts/pointinpoly/default.html | |
| 11 // return true if pt is inside triangle; false if outside or on the line | |
| 12 bool SkDTriangle::contains(const SkDPoint& pt) const { | |
| 13 // Compute vectors | |
| 14 SkDVector v0 = fPts[2] - fPts[0]; | |
| 15 SkDVector v1 = fPts[1] - fPts[0]; | |
| 16 SkDVector v2 = pt - fPts[0]; | |
| 17 | |
| 18 // Compute dot products | |
| 19 double dot00 = v0.dot(v0); | |
| 20 double dot01 = v0.dot(v1); | |
| 21 double dot02 = v0.dot(v2); | |
| 22 double dot11 = v1.dot(v1); | |
| 23 double dot12 = v1.dot(v2); | |
| 24 | |
| 25 // original code doesn't handle degenerate input; isn't symmetric with inclusion of corner pts; | |
| 26 // introduces necessary error with divide; doesn't short circuit on early answer | |
| 27 #if 0 | |
| 28 // Compute barycentric coordinates | |
| 29 double invDenom = 1 / (dot00 * dot11 - dot01 * dot01); | |
| 30 double u = (dot11 * dot02 - dot01 * dot12) * invDenom; | |
| 31 double v = (dot00 * dot12 - dot01 * dot02) * invDenom; | |
| 32 | |
| 33 // Check if point is in triangle | |
| 34 return (u >= 0) && (v >= 0) && (u + v <= 1); | |
| 35 #else | |
| 36 double w = dot00 * dot11 - dot01 * dot01; | |
| 37 if (w == 0) { | |
| 38 return false; | |
| 39 } | |
| 40 double wSign = w < 0 ? -1 : 1; | |
| 41 double u = (dot11 * dot02 - dot01 * dot12) * wSign; | |
| 42 if (u <= 0) { | |
| 43 return false; | |
| 44 } | |
| 45 double v = (dot00 * dot12 - dot01 * dot02) * wSign; | |
| 46 if (v <= 0) { | |
| 47 return false; | |
| 48 } | |
| 49 return u + v < w * wSign; | |
| 50 #endif | |
| 51 } |
