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Diffstat (limited to 'common/polygon.cpp')
| -rw-r--r-- | common/polygon.cpp | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/common/polygon.cpp b/common/polygon.cpp new file mode 100644 index 0000000000..4a41d127d5 --- /dev/null +++ b/common/polygon.cpp @@ -0,0 +1,55 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + */ + +#include "common/polygon.h" + +namespace Common { + +bool Polygon::contains(int16 x, int16 y) const { + int yflag0; + int yflag1; + bool inside_flag = false; + unsigned int pt; + + const Point *vtx0 = &points[points.size() - 1]; + const Point *vtx1 = &points[0]; + + yflag0 = (vtx0->y >= y); + for (pt = 0; pt < points.size(); pt++, vtx1++) { + yflag1 = (vtx1->y >= y); + if (yflag0 != yflag1) { + if (((vtx1->y - y) * (vtx0->x - vtx1->x) >= + (vtx1->x - x) * (vtx0->y - vtx1->y)) == yflag1) { + inside_flag = !inside_flag; + } + } + yflag0 = yflag1; + vtx0 = vtx1; + } + + return inside_flag; +} + +} // end of namespace Common |