78 lines
2.3 KiB
C++
78 lines
2.3 KiB
C++
/* Copyright (C) 2014 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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#ifndef INCLUDED_BOUNDINGSPHERE
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#define INCLUDED_BOUNDINGSPHERE
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#include "maths/BoundingBoxAligned.h"
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#include "maths/Vector3D.h"
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class CBoundingSphere
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{
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private:
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CVector3D m_Center;
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float m_Radius;
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public:
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CBoundingSphere() : m_Radius(0) { }
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CBoundingSphere(const CVector3D& center, float radius) : m_Center(center), m_Radius(radius) { }
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/**
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* Construct a bounding sphere that encompasses a bounding box
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* swept through all possible rotations around the origin.
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*/
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static CBoundingSphere FromSweptBox(const CBoundingBoxAligned& bbox)
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{
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float maxX = std::max(fabsf(bbox[0].X), fabsf(bbox[1].X));
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float maxY = std::max(fabsf(bbox[0].Y), fabsf(bbox[1].Y));
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float maxZ = std::max(fabsf(bbox[0].Z), fabsf(bbox[1].Z));
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float radius = sqrtf(maxX*maxX + maxY*maxY + maxZ*maxZ);
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return CBoundingSphere(CVector3D(0.f, 0.f, 0.f), radius);
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}
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const CVector3D& GetCenter()
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{
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return m_Center;
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}
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float GetRadius() const
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{
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return m_Radius;
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}
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/**
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* Check if the ray, defined by an origin point and a direction unit vector
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* interesects with the sphere
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*/
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bool RayIntersect(const CVector3D& origin, const CVector3D& dir) const
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{
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CVector3D v = m_Center - origin; // Vector v from the origin of the ray to the center of the sphere
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float pcLen = dir.Dot(v); // Length of the projection of v onto the direction vector of the ray
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if(pcLen <= 0)
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return false; // Sphere behind the ray
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// Get the shortest distance from the center of the sphere to the ray
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v = (dir * pcLen) - v;
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if (v.LengthSquared() > m_Radius * m_Radius)
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return false; // Distance to sphere center more than radius
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return true;
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}
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};
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#endif // INCLUDED_BOUNDINGSPHERE
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