/****************************************************************************
 Copyright (c) 2015 Chukong Technologies Inc.
 
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 of this software and associated documentation files (the "Software"), to deal
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 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,
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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 ****************************************************************************/

#include "CCPUParticle3DInterParticleCollider.h"
#include "extensions/Particle3D/ParticleUniverse/CCPUParticleSystem3D.h"

NS_CC_BEGIN

// Constants
const float PUParticle3DInterParticleCollider::DEFAULT_ADJUSTMENT = 1.0f;
const PUParticle3DInterParticleCollider::InterParticleCollisionResponse PUParticle3DInterParticleCollider::DEFAULT_COLLISION_RESPONSE = 
         PUParticle3DInterParticleCollider::IPCR_AVERAGE_VELOCITY;

//-----------------------------------------------------------------------
PUParticle3DInterParticleCollider::PUParticle3DInterParticleCollider(void) : 
    PUParticle3DBaseCollider(),
    _adjustment(DEFAULT_ADJUSTMENT),
    _interParticleCollisionResponse(DEFAULT_COLLISION_RESPONSE)
{
}

PUParticle3DInterParticleCollider::~PUParticle3DInterParticleCollider( void )
{

}
//-----------------------------------------------------------------------
float PUParticle3DInterParticleCollider::getAdjustment(void) const
{
    return _adjustment;
}
//-----------------------------------------------------------------------
void PUParticle3DInterParticleCollider::setAdjustment(float adjustment)
{
    _adjustment = adjustment;
}
//-----------------------------------------------------------------------
PUParticle3DInterParticleCollider::InterParticleCollisionResponse PUParticle3DInterParticleCollider::getInterParticleCollisionResponse(void) const
{
    return _interParticleCollisionResponse;
}
//-----------------------------------------------------------------------
void PUParticle3DInterParticleCollider::setInterParticleCollisionResponse(PUParticle3DInterParticleCollider::InterParticleCollisionResponse interParticleCollisionResponse)
{
    _interParticleCollisionResponse = interParticleCollisionResponse;
}
//-----------------------------------------------------------------------
void PUParticle3DInterParticleCollider::prepare()
{
    // Activate spatial hashing
    //particleTechnique->setSpatialHashingUsed(true);
}
//-----------------------------------------------------------------------
void PUParticle3DInterParticleCollider::unPrepare()
{
    // Deactivate spatial hashing
    //particleTechnique->setSpatialHashingUsed(false);
}
//-----------------------------------------------------------------------
bool PUParticle3DInterParticleCollider::validateAndExecuteSphereCollision (PUParticle3D* particle1, PUParticle3D* particle2, float timeElapsed)
{
    PUParticle3D* vp1 = static_cast<PUParticle3D*>(particle1);
    PUParticle3D* vp2 = static_cast<PUParticle3D*>(particle2);
    if ((vp1->position - vp2->position).length() < _adjustment * (vp1->radius + vp2->radius))
    {
        /** Collision detected.
        @remarks
            The collision response calculation isn't accurate, but gives an acceptable result.
        */
        Vec3 n = vp1->position - vp2->position;
        n.normalize();
        switch(_interParticleCollisionResponse)
        {
            case IPCR_AVERAGE_VELOCITY:
            {
                // Use average velocity; this keeps the particles in movement.
                float velocity1 = vp1->direction.length();
                float velocity2 = vp2->direction.length();
                float averageVelocity = 0.5f * (velocity1 + velocity2);
                vp1->direction = averageVelocity * vp2->mass * n;
                vp2->direction = averageVelocity * vp1->mass * -n;
            }
            break;

            case IPCR_ANGLE_BASED_VELOCITY:
            {
                // The new velocity is based on the angle between original direction and new direction.
                // Note, that this usually means that the velocity decreases.

                float velocity1 = Vec3(abs(vp1->direction.x), abs(vp1->direction.y), abs(vp1->direction.z)).dot(n);
                float velocity2 = Vec3(abs(vp2->direction.x), abs(vp2->direction.y), abs(vp2->direction.z)).dot(n);
                vp1->direction = velocity1 * vp2->mass * n;
                vp2->direction = velocity2 * vp1->mass * -n;
            }
            break;
        }
        vp1->direction *= _bouncyness;
        vp2->direction *= _bouncyness;
        vp1->addEventFlags(PUParticle3D::PEF_COLLIDED);
        vp2->addEventFlags(PUParticle3D::PEF_COLLIDED);
        return true;
    }

    return false;
}
//-----------------------------------------------------------------------

void PUParticle3DInterParticleCollider::updatePUAffector( PUParticle3D *particle, float deltaTime )
{
    //CCASSERT(0, "nonsupport yet");
    //for (auto iter : _particleSystem->getParticles())
    //{
    //    PUParticle3D *particle = iter;
    //     Fast rejection: only visible, moving particles are able to collide, unless they are colliding already
    //     Changed && into || in V1.3.1
    //    if (//particle->particleType != Particle::PT_VISUAL || 
    //        particle->hasEventFlags(PUParticle3D::PEF_COLLIDED) || 
    //        particle->direction == Vec3::ZERO)
    //    {
    //        return;
    //    }

    //    // Determine whether neighbour particles are colliding.
    //    SpatialHashTable<Particle*>* hashtable = particleTechnique->getSpatialHashTable();
    //    if (hashtable)
    //    {
    //    	SpatialHashTable<Particle*>::HashTableCell cell = hashtable->getCell(particle->position);
    //    	if (cell.empty())
    //    		return;

    //    	unsigned int size = static_cast<unsigned int>(cell.size());
    //    	for (unsigned int i = 0; i < size; ++i)
    //    	{
    //    		Particle* p = cell[i];

    //    		// Don't check if it is the same particle or the particle is already colliding.
    //    		if (particle != p  && !p->hasEventFlags(PUParticle3D::PEF_COLLIDED))
    //    		{
    //    			// Check for collision
    //    			if (validateAndExecuteSphereCollision(particle, p, deltaTime))
    //    			{
    //    				return;
    //    			}
    //    		}
    //    	}
    //    }
    //}
}

PUParticle3DInterParticleCollider* PUParticle3DInterParticleCollider::create()
{
    auto pipc = new (std::nothrow) PUParticle3DInterParticleCollider();
    pipc->autorelease();
    return pipc;
}

NS_CC_END