/*
--------------------------------------------------------------------------------
This source file is part of SkyX.
Visit http://www.paradise-studios.net/products/skyx/

Copyright (C) 2009-2011 Xavier Verguín González <xavyiy@gmail.com>

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
--------------------------------------------------------------------------------
*/

#include "VClouds/Ellipsoid.h"

namespace SkyX { namespace VClouds
{

     Ellipsoid::Ellipsoid(
		const int &a, const int &b, const int &c, 
		const int &nx, const int &ny, const int &nz, 
		const int &x, const int &y, const int &z,
		const Ogre::Real& Density)
		: mA(a), mB(b), mC(c)
		, mA2(Ogre::Math::Pow(a, 2)), mB2(Ogre::Math::Pow(b, 2)), mC2(Ogre::Math::Pow(c, 2))
		, mNx(nx), mNy(ny), mNz(nz)
		, mX(x), mY(y), mZ(z)
		, mDensity(Density)
	{
	}

	Ellipsoid::~Ellipsoid()
	{
	}

	const float Ellipsoid::_getLength(const int &x, const int &y, const int &z) const
	{
		//  x^2   y^2   z^2
		//  /   + /   + /    = 1  (Ellipsoid ecuation)
		//  a^2   b^2   c^2
		// 
		//  maxradatdir = lambda (Xo, Yo, Zo) = lambda; where Xo, Yo and Zo are the components of the normaliced direction vector
		//
		//  => lambda^2 = 1 / ( EllipsoidEcuation...)
		//
		//  => lambda = sqrt (...) => maxradatdir = lambda

		Ogre::Vector3 Direction = Ogre::Vector3(x-mX, y-mY, z-mZ),
					  DirectionNormalized = Direction.normalisedCopy();

		Ogre::Real a = Ogre::Math::Pow(DirectionNormalized.x, 2) / mA2 + 
				       Ogre::Math::Pow(DirectionNormalized.y, 2) / mB2 +
				       Ogre::Math::Pow(DirectionNormalized.z, 2) / mC2,

		           lambda = 1.0f / Ogre::Math::Sqrt(a);

		return Ogre::Math::Clamp<Ogre::Real>(Direction.length() / lambda, 0, 1);
	}

	const Ogre::Vector3 Ellipsoid::getProbabilities(const int& x, const int& y, const int& z) const
	{
		float density = Ogre::Math::Pow(1-_getLength(x, y, z), 1.0f/mDensity);

		return Ogre::Vector3(density, 1-density, density);
	}

    void Ellipsoid::updateProbabilities(DataManager::Cell ***c, const int &nx, const int &ny, const int &nz, const bool& delayedResponse)
	{
		int u, v, w, uu, vv;

		float length;

		for (u = mX-mA; u < mX+mA; u++)
		{
			uu = (u<0) ? (u + nx) : u; if (u>=nx) { uu-= nx; }

			for (v = mY-mB; v < mY+mB; v++)
			{
				vv = (v<0) ? (v + ny) : v; if (v>=ny) { vv-= ny; }

				for (w = mZ-mC; w < mZ+mC; w++)
				{
					length = _getLength(u, v, w);

					if (length < 1)
					{
						c[uu][vv][w].phum = 0.005f;
						c[uu][vv][w].pext = 0.05f;
						c[uu][vv][w].pact = 0.01f;

						if (!delayedResponse)
						{
							c[uu][vv][w].cld = Ogre::Math::RangeRandom(0,1) > length ? true : false;
						}
					}
				}
			}
		}
	}

	void Ellipsoid::move(const int& Ax, const int& Ay, const int& Az)
	{
		mX += Ax; mY += Ay; mZ += Az;
	}

	const bool Ellipsoid::isOutOfCells() const
	{
		if ( (mX+mA) >= mNx || (mX-mA) < 0 ||
			 (mY+mB) >= mNy || (mY-mB) < 0 ||
			 (mZ+mZ) >= mNz || (mZ-mZ) < 0 )
		{
			return true;
		}

		return false;
	}

	void Ellipsoid::setDimensions(const Ogre::Vector3& Dimensions)
	{
		mA = Dimensions.x; 
		mB = Dimensions.y; 
		mC = Dimensions.z;

		mA2 = Ogre::Math::Pow(mA, 2); 
		mB2 = Ogre::Math::Pow(mB, 2); 
		mC2 = Ogre::Math::Pow(mC, 2);
	}

}}