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/* ScummVM - Scumm Interpreter
* Copyright (C) 2004 The ScummVM project
*
* The ReInherit Engine is (C)2000-2003 by Daniel Balsom.
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Header$
*
*/
/*
Description:
Math routines
Notes:
*/
#include <stdio.h>
#include <stdlib.h>
#include "reinherit.h"
namespace Saga {
int
MATH_HitTestPoly(R_POINT * points, unsigned int npoints, R_POINT test_point)
{
int yflag0;
int yflag1;
int inside_flag = 0;
unsigned int pt;
R_POINT *vtx0 = &points[npoints - 1];
R_POINT *vtx1 = &points[0];
yflag0 = (vtx0->y >= test_point.y);
for (pt = 0; pt < npoints; pt++, vtx1++) {
yflag1 = (vtx1->y >= test_point.y);
if (yflag0 != yflag1) {
if (((vtx1->y - test_point.y) * (vtx0->x - vtx1->x) >=
(vtx1->x - test_point.x) * (vtx0->y -
vtx1->y)) == yflag1) {
inside_flag = !inside_flag;
}
}
yflag0 = yflag1;
vtx0 = vtx1;
}
return inside_flag;
}
} // End of namespace Saga
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