scummvm/backends/vkeybd/polygon.cpp
2011-05-12 01:16:22 +02:00

59 lines
1.6 KiB
C++

/* 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.
*
*/
#include "common/scummsys.h"
#ifdef ENABLE_VKEYBD
#include "backends/vkeybd/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
#endif // #ifdef ENABLE_VKEYBD