62 lines
1.7 KiB
C++
62 lines
1.7 KiB
C++
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// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
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// Copyright (C) 2010 Winch Gate Property Limited
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as
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// published by the Free Software Foundation, either version 3 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#include "stdpacs.h"
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#include "nel/pacs/vector_2s.h"
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namespace NLPACS {
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// Test if 2 segments intersects
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bool CVector2s::intersect(const CVector2s& a0, const CVector2s& a1, const CVector2s& b0, const CVector2s& b1, double* pa, double* pb)
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{
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double a0x = CVector2s::unpack(a0.x);
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double a0y = CVector2s::unpack(a0.y);
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double a1x = CVector2s::unpack(a1.x);
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double a1y = CVector2s::unpack(a1.y);
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double b0x = CVector2s::unpack(b0.x);
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double b0y = CVector2s::unpack(b0.y);
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double b1x = CVector2s::unpack(b1.x);
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double b1y = CVector2s::unpack(b1.y);
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double ax = +(a1x-a0x);
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double ay = +(a1y-a0y);
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double bx = +(b1x-b0x);
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double by = +(b1y-b0y);
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double cx = +(b0x-a0x);
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double cy = +(b0y-a0y);
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double d = -ax*by + ay*bx;
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if (d == 0.0)
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return false;
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double a = (bx*cy - by*cx) / d;
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double b = (ax*cy - ay*cx) / d;
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if (pa != NULL)
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*pa = a;
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if (pb != NULL)
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*pb = b;
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return d != 0.0 && a >= 0.0 && a <= 1.0 && b >= 0.0 && b <= 1.0;
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}
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} // NLPACS
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