Cube.h

/*
Pharmit
Copyright (c) David Ryan Koes, University of Pittsburgh and contributors.
All rights reserved.

Pharmit is licensed under both the BSD 3-clause license and the GNU
Public License version 2. Any use of the code that retains its reliance
on the GPL-licensed OpenBabel library is subject to the terms of the GPL2.

Use of the Pharmit code independently of OpenBabel (or any other
GPL2 licensed software) may choose between the BSD or GPL licenses.

See the LICENSE file provided with the distribution for more information.

*/
/*
 * Cube.h
 *
 * A simple class for representing a cube.
 *  Created on: Sep 28, 2011
 *      Author: dkoes
 */

#ifndef CUBE_H_
#define CUBE_H_

#include <cmath>
#include <cfloat>
#include <algorithm>
using namespace std;

/* A cube. Functions for consistently dividing into octants */
class Cube
{
public:
	float x, y, z; //bottom corner
	float dim;

	inline float squared(float v) const
	{
		return v * v;
	}

	//find the minimum distance between line segements a1-a2 and b1-b2
	inline float min1dist(float a1, float a2, float b1, float b2) const
	{
		//eh, just try all combos
		return min(min(fabs(a1-b2),fabs(a1-b1)),min(fabs(a2-b2),fabs(a2-b1)));
	}
public:

	Cube(float d) :
		x(0), y(0), z(0), dim(d)
	{

	}

	Cube(float d, float X, float Y, float Z): x(X), y(Y), z(Z), dim(d) {}

	float getDimension() const
	{
		return dim;
	}

	float volume() const
	{
		return dim*dim*dim;
	}

	void getCenter(float& cx, float& cy, float& cz) const
	{
		cx = x+dim/2;
		cy = y+dim/2;
		cz = z+dim/2;
	}

	void getBottomCorner(float& bx, float& by, float& bz) const
	{
		bx = x;
		by = y;
		bz = z;
	}

	//return i'th octant
	Cube getOctant(unsigned i) const
	{
		Cube res = *this;
		res.dim /= 2.0;

		switch (i)
		{
		case 0:
			break;
		case 1:
			res.x += res.dim;
			break;
		case 2:
			res.y += res.dim;
			break;
		case 3:
			res.x += res.dim;
			res.y += res.dim;
			break;
		case 4:
			res.z += res.dim;
			break;
		case 5:
			res.x += res.dim;
			res.z += res.dim;
			break;
		case 6:
			res.y += res.dim;
			res.z += res.dim;
			break;
		case 7:
			res.x += res.dim;
			res.y += res.dim;
			res.z += res.dim;
			break;
		default:
			abort();
			break;
		}
		return res;
	}

	//shortest distance from this cube to rhs
	float minDist(const Cube& rhs) const
	{
		float minx = min1dist(x, x+dim, rhs.x, rhs.x+rhs.dim);
		float miny = min1dist(y, y+dim, rhs.y, rhs.y+rhs.dim);
		float minz = min1dist(z, z+dim, rhs.z, rhs.z+rhs.dim);

		return sqrt(minx*minx+miny*miny+minz*minz);
	}
};

#endif /* CUBE_H_ */