/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2009 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/
#include "OgreColourImageAffector.h"
#include "OgreParticleSystem.h"
#include "OgreStringConverter.h"
#include "OgreParticle.h"
#include "OgreException.h"
#include "OgreResourceGroupManager.h"

namespace Ogre {
    
    // init statics
	ColourImageAffector::CmdImageAdjust		ColourImageAffector::msImageCmd;

    //-----------------------------------------------------------------------
    ColourImageAffector::ColourImageAffector(ParticleSystem* psys)
        :ParticleAffector(psys), mColourImageLoaded(false)
    {
        mType = "ColourImage";

        // Init parameters
        if (createParamDictionary("ColourImageAffector"))
        {
            ParamDictionary* dict = getParamDictionary();

			dict->addParameter(ParameterDef("image", "image where the colours come from", PT_STRING), &msImageCmd);
        }
    }
    //-----------------------------------------------------------------------
    void ColourImageAffector::_initParticle(Particle* pParticle)
	{
        if (!mColourImageLoaded)
        {
            _loadImage();
        }

        pParticle->colour = mColourImage.getColourAt(0, 0, 0);
    
	}
    //-----------------------------------------------------------------------
    void ColourImageAffector::_affectParticles(ParticleSystem* pSystem, Real timeElapsed)
    {
        Particle*			p;
		ParticleIterator	pi				= pSystem->_getIterator();

        if (!mColourImageLoaded)
        {
            _loadImage();
        }

		int				   width			= (int)mColourImage.getWidth()  - 1;
        
		while (!pi.end())
		{
			p = pi.getNext();
			const Real		life_time		= p->totalTimeToLive;
			Real			particle_time	= 1.0f - (p->timeToLive / life_time); 

			if (particle_time > 1.0f)
				particle_time = 1.0f;
			if (particle_time < 0.0f)
				particle_time = 0.0f;

			const Real		float_index		= particle_time * width;
			const int		index			= (int)float_index;

            if(index < 0)
            {
				p->colour = mColourImage.getColourAt(0, 0, 0);
            }
            else if(index >= width) 
            {
                p->colour = mColourImage.getColourAt(width, 0, 0);
            }
            else
            {
                // Linear interpolation
				const Real		fract		= float_index - (Real)index;
				const Real		to_colour	= fract;
				const Real		from_colour	= 1.0f - to_colour;
             
                ColourValue from=mColourImage.getColourAt(index, 0, 0),
							to=mColourImage.getColourAt(index+1, 0, 0);

				p->colour.r = from.r*from_colour + to.r*to_colour;
                p->colour.g = from.g*from_colour + to.g*to_colour;
                p->colour.b = from.b*from_colour + to.b*to_colour;
                p->colour.a = from.a*from_colour + to.a*to_colour;
			}
		}
    }
    
    //-----------------------------------------------------------------------
    void ColourImageAffector::setImageAdjust(String name)
    {
		mColourImageName = name;
        mColourImageLoaded = false;
	}
    //-----------------------------------------------------------------------
    void ColourImageAffector::_loadImage(void)
    {
        mColourImage.load(mColourImageName, mParent->getResourceGroupName());

		PixelFormat	format = mColourImage.getFormat();

		if ( !PixelUtil::isAccessible(format) )
		{
			OGRE_EXCEPT( Exception::ERR_INVALIDPARAMS, "Error: Image is not accessible (rgba) image.",
					"ColourImageAffector::_loadImage" );
		}

        mColourImageLoaded = true;
	}
    //-----------------------------------------------------------------------
    String ColourImageAffector::getImageAdjust(void) const
    {
        return mColourImageName;
    }
    
	
	//-----------------------------------------------------------------------
    //-----------------------------------------------------------------------
    //-----------------------------------------------------------------------
    // Command objects
    //-----------------------------------------------------------------------
    //-----------------------------------------------------------------------
    String ColourImageAffector::CmdImageAdjust::doGet(const void* target) const
    {
        return static_cast<const ColourImageAffector*>(target)->getImageAdjust();
    }
    void ColourImageAffector::CmdImageAdjust::doSet(void* target, const String& val)
    {
        static_cast<ColourImageAffector*>(target)->setImageAdjust(val);
    }

}