forked from 0ad/0ad
114 lines
2.7 KiB
C++
114 lines
2.7 KiB
C++
/* Copyright (C) 2009 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* A Plane in R3 and several utility methods.
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*/
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// Note that the format used for the plane equation is
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// Ax + By + Cz + D = 0, where <A,B,C> is the normal vector.
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#include "precompiled.h"
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#include "Plane.h"
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#include "MathUtil.h"
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const float CPlane::m_EPS = 0.001f;
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CPlane::CPlane()
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{
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m_Dist = 0.0f;
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}
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//sets the plane equation from 3 points on that plane
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void CPlane::Set(const CVector3D& p1, const CVector3D& p2, const CVector3D& p3)
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{
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CVector3D D1, D2;
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CVector3D Norm;
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//calculate two vectors on the surface of the plane
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D1 = p2-p1;
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D2 = p3-p1;
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//cross multiply gives normal
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Norm = D2.Cross(D1);
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Set(Norm, p1);
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}
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//sets the plane equation from a normal and a point on
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//that plane
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void CPlane::Set(const CVector3D& norm, const CVector3D& point)
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{
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m_Norm = norm;
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m_Dist = - (norm.X * point.X + norm.Y * point.Y + norm.Z * point.Z);
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// Normalize ();
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}
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//normalizes the plane equation
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void CPlane::Normalize()
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{
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float Scale = 1.0f/m_Norm.Length();
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m_Norm.X *= Scale;
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m_Norm.Y *= Scale;
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m_Norm.Z *= Scale;
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m_Dist *= Scale;
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}
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//returns the side of the plane on which this point
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//lies.
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PLANESIDE CPlane::ClassifyPoint(const CVector3D& point) const
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{
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float Dist = DistanceToPlane(point);
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if (Dist > m_EPS)
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return PS_FRONT;
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else if (Dist < -m_EPS)
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return PS_BACK;
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return PS_ON;
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}
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//calculates the intersection point of a line with this
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//plane. Returns false if there is no intersection
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bool CPlane::FindLineSegIntersection(const CVector3D& start, const CVector3D& end, CVector3D* intsect) const
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{
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float dist1 = DistanceToPlane(start);
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float dist2 = DistanceToPlane(end);
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if( (dist1 < 0 && dist2 < 0) || (dist1 >= 0 && dist2 >= 0) )
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return false;
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float t = (-dist1) / (dist2-dist1);
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*intsect = Interpolate(start, end, t);
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return true;
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}
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bool CPlane::FindRayIntersection(const CVector3D& start, const CVector3D& direction, CVector3D* intsect) const
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{
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float dot = m_Norm.Dot(direction);
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if (dot == 0.0f)
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return false;
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*intsect = start - (direction * (DistanceToPlane(start)/dot));
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return true;
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}
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