/*
--------------------------------------------------------------------------------
This source file is part of Hydrax.
Visit http://www.ogre3d.org/tikiwiki/Hydrax

Copyright (C) 2011 Jose Luis Cercós Pita <jlcercos@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 the main header
// ----------------------------------------------------------------------------
#include <Noise/Real/HydraxPressurePoint.h>

// ----------------------------------------------------------------------------
// Include Hydrax
// ----------------------------------------------------------------------------
#include <Hydrax.h>

#define _def_PackedNoise true

#ifndef _LN001_
    #define _LN001_ -4.605170186f
#endif

// 0 = linear decay function
// 1 = exponential decay function
// 2 = cuadratic decay function
#define _DECAYFUNCTION_ 2

using namespace Hydrax::Noise;

PressurePoint::PressurePoint(Ogre::Vector2 Orig, float p, float T, float L)
    : mTime(0)
    , mPos(Orig)
    , mP(p)
    , mT(T)
    , mL(L)
{
    mA = mP / _HydraxDensity_ / _HydraxGravity_;
    mK = 2.f * static_cast<float>(M_PI) / mL;
    mC = 5.f*sqrt(mL);
    mW = mC*mK;
}

PressurePoint::~PressurePoint()
{
}

bool PressurePoint::update(const Ogre::Real &timeSinceLastFrame)
{
    mTime += timeSinceLastFrame;
    if(mTime >= mT) {
        mK1 = 0.f;
        return false;
    }

    mK1 = exp(_LN001_/mT*static_cast<float>(mTime)) - 0.01f;

    return true;
}

float PressurePoint::getValue(const float &x, const float &y)
{
    //! 1st.- Calculate distance.
    float R = mC*static_cast<float>(mTime);
    float dx = x - mPos.x;
    if(dx > R)
        return 0.f;
    float dy = y - mPos.y;
    if(dy > R)
        return 0.f;
    #if _DECAYFUNCTION_ == 0
        float r = sqrt(dx*dx + dy*dy);
    #elif _DECAYFUNCTION_ == 1
        float r = sqrt(dx*dx + dy*dy);
    #elif _DECAYFUNCTION_ == 2
        float r = dx*dx + dy*dy;
        float R2 = R*R;
    #endif
    //! 2nd.- Calculate time decay factors
    if(mTime >= mT)
        return 0.f;
    //! 2nd.- Calculate distance decay factors
    if(r >= R)
        return 0.f;
    #if _DECAYFUNCTION_ == 0
        mK2 = 1.f - r/R;
    #elif _DECAYFUNCTION_ == 1
        mK2 = exp(_LN001_*r/R) - 0.01f;
    #elif _DECAYFUNCTION_ == 2
        float f = r/R2;
        mK2 = 1.f - f;
        r = f*R;
    #endif
    //! 3rd.- Calculate height
    return mK1*mK2*mA*sin(mW*static_cast<float>(mTime) - mK*r);
}