130 lines
2.9 KiB
C++
130 lines
2.9 KiB
C++
// 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 "stdmisc.h"
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#include "nel/misc/grid_traversal.h"
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#include "nel/misc/vector_2f.h"
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#ifdef DEBUG_NEW
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#define new DEBUG_NEW
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#endif
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namespace NLMISC
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{
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// ********************************************************************************************************************************
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void CGridTraversal::startTraverse(const NLMISC::CVector2f &start, sint &nextX, sint &nextY)
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{
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nextX = (sint) floorf(start.x);
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nextY = (sint) floorf(start.y);
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}
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// ********************************************************************************************************************************
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bool CGridTraversal::traverse(const NLMISC::CVector2f &start, const NLMISC::CVector2f &dir, sint &x, sint &y)
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{
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if (dir.x > 0.f)
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{
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float lambdaX = (x + 1.f - start.x) / dir.x;
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if (dir.y > 0.f)
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{
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float lambdaY = (y + 1 - start.y) / dir.y;
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if (lambdaX < lambdaY)
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{
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if (lambdaX > 1.f) return false;
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++ x;
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return true;
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}
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else
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{
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if (lambdaY > 1.f) return false;
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++ y;
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return true;
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}
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}
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else if (dir.y < 0.f)
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{
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float lambdaY = (y - start.y) / dir.y;
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if (lambdaX < lambdaY)
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{
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if (lambdaX > 1.f) return false;
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++ x;
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return true;
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}
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else
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{
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if (lambdaY > 1.f) return false;
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-- y;
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return true;
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}
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}
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++ x;
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return x <= (sint) floorf(start.x + dir.x);
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}
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else if (dir.x < 0.f)
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{
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float lambdaX = (x - start.x) / dir.x;
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if (dir.y > 0.f)
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{
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float lambdaY = (y + 1.f - start.y) / dir.y;
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if (lambdaX < lambdaY)
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{
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if (lambdaX > 1.f) return false;
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-- x;
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return true;
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}
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else
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{
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if (lambdaY > 1.f) return false;
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++ y;
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return true;
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}
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}
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else if (dir.y < 0.f)
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{
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float lambdaY = (y - start.y) / dir.y;
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if (lambdaX < lambdaY)
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{
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if (lambdaX > 1.f) return false;
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-- x;
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return true;
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}
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else
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{
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if (lambdaY > 1.f) return false;
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-- y;
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return true;
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}
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}
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-- x;
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return x >= (sint) floorf(start.x + dir.x);
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}
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if (dir.y > 0.f)
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{
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++ y;
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return y <= (sint) floorf(start.y + dir.y);
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}
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else if (dir.y < 0.f)
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{
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-- y;
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return y >= (sint) floorf(start.y + dir.y);
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}
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return false;
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}
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} // NLMISC
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