// This file is part of the OGRE project.

// It is subject to the license terms in the LICENSE file found in the top-level directory

// of this distribution and at https://www.ogre3d.org/licensing.

// SPDX-License-Identifier: MIT

#include "OgreTextureAnimatorAffector.h"

#include "OgreParticleSystem.h"

#include "OgreStringConverter.h"

#include "OgreParticle.h"

namespace Ogre {

class CmdStart : public ParamCommand

{

public:

    String doGet(const void* target) const override

    {

        return StringConverter::toString(

            static_cast<const TextureAnimatorAffector*>(target)->getTexcoordStart());

    }

    void doSet(void* target, const String& val) override

    {

        static_cast<TextureAnimatorAffector*>(target)->setTexcoordStart(StringConverter::parseInt(val));

    }

};

class CmdCount : public ParamCommand

{

public:

    String doGet(const void* target) const override

    {

        return StringConverter::toString(

            static_cast<const TextureAnimatorAffector*>(target)->getTexcoordCount());

    }

    void doSet(void* target, const String& val) override

    {

        static_cast<TextureAnimatorAffector*>(target)->setTexcoordCount(StringConverter::parseInt(val));

    }

};

class CmdDuration : public ParamCommand

{

public:

    String doGet(const void* target) const override

    {

        return StringConverter::toString(

            static_cast<const TextureAnimatorAffector*>(target)->getDuration());

    }

    void doSet(void* target, const String& val) override

    {

        static_cast<TextureAnimatorAffector*>(target)->setDuration(StringConverter::parseReal(val));

    }

};

class CmdOffset : public ParamCommand

{

public:

    String doGet(const void* target) const override

    {

        return StringConverter::toString(

            static_cast<const TextureAnimatorAffector*>(target)->isRandomStartOffset());

    }

    void doSet(void* target, const String& val) override

    {

        static_cast<TextureAnimatorAffector*>(target)->useRandomStartOffset(StringConverter::parseBool(val));

    }

};

    // init statics

    static CmdStart msStartCmd;

    static CmdCount msCountCmd;

    static CmdDuration msDurationCmd;

    static CmdOffset msOffset;

    //-----------------------------------------------------------------------

    TextureAnimatorAffector::TextureAnimatorAffector(ParticleSystem* psys) : ParticleAffector(psys)

    {

        mTexcoordStart = mTexcoordCount = mDuration = 0;

        mRandomStartOffset = false;

        mType = "TextureAnimator";

        // Init parameters

        if (createParamDictionary("TextureAnimatorAffector"))

        {

            ParamDictionary* dict = getParamDictionary();

            dict->addParameter(ParameterDef("texcoord_start", "", PT_INT), &msStartCmd);

            dict->addParameter(ParameterDef("texcoord_count", "", PT_INT), &msCountCmd);

            dict->addParameter(ParameterDef("duration", "", PT_REAL), &msDurationCmd);

            dict->addParameter(ParameterDef("random_offset", "", PT_BOOL), &msOffset);

        }

    }

    //-----------------------------------------------------------------------

    void TextureAnimatorAffector::_initParticle(Particle* pParticle)

    {

        pParticle->mTexcoordIndex = 0;

        if (!mRandomStartOffset)

            return;

        pParticle->mRandomTexcoordOffset = Math::UnitRandom() * mTexcoordCount;

        pParticle->mTexcoordIndex = pParticle->mRandomTexcoordOffset;

    }

    void TextureAnimatorAffector::_affectParticles(ParticleSystem* pSystem, Real timeElapsed)

    {

        // special case: randomly pick one cell in sprite-sheet

        if(mDuration < 0)

            return;

        for (auto p : pSystem->_getActiveParticles())

        {

            float particle_time = 1.0f - (p->mTimeToLive / p->mTotalTimeToLive);

            float speed = mDuration ? (p->mTotalTimeToLive / mDuration) : 1.0f;

            uint8 idx = uint8(particle_time * speed * mTexcoordCount + p->mRandomTexcoordOffset) % mTexcoordCount;

            p->mTexcoordIndex = idx + mTexcoordStart;

        }

    }

}