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/* Copyright (C) 2014 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_BOUNDINGSPHERE
#define INCLUDED_BOUNDINGSPHERE
#include "maths/BoundingBoxAligned.h"
#include "maths/Vector3D.h"
class CBoundingSphere
{
private:
CVector3D m_Center;
float m_Radius;
public:
CBoundingSphere() : m_Radius(0) { }
CBoundingSphere(const CVector3D& center, float radius) : m_Center(center), m_Radius(radius) { }
/**
* Construct a bounding sphere that encompasses a bounding box
* swept through all possible rotations around the origin.
*/
static CBoundingSphere FromSweptBox(const CBoundingBoxAligned& bbox)
{
float maxX = std::max(fabsf(bbox[0].X), fabsf(bbox[1].X));
float maxY = std::max(fabsf(bbox[0].Y), fabsf(bbox[1].Y));
float maxZ = std::max(fabsf(bbox[0].Z), fabsf(bbox[1].Z));
float radius = sqrtf(maxX*maxX + maxY*maxY + maxZ*maxZ);
return CBoundingSphere(CVector3D(0.f, 0.f, 0.f), radius);
}
const CVector3D& GetCenter()
{
return m_Center;
}
float GetRadius() const
{
return m_Radius;
}
/**
* Check if the ray, defined by an origin point and a direction unit vector
* interesects with the sphere
*/
bool RayIntersect(const CVector3D& origin, const CVector3D& dir) const
{
CVector3D v = m_Center - origin; // Vector v from the origin of the ray to the center of the sphere
float pcLen = dir.Dot(v); // Length of the projection of v onto the direction vector of the ray
if(pcLen <= 0)
return false; // Sphere behind the ray
// Get the shortest distance from the center of the sphere to the ray
v = (dir * pcLen) - v;
if (v.LengthSquared() > m_Radius * m_Radius)
return false; // Distance to sphere center more than radius
return true;
}
};
#endif // INCLUDED_BOUNDINGSPHERE
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