// Copyright (C) 2002-2007 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "IrrCompileConfig.h"
#include "CParticleAttractionAffector.h"
#include "os.h"

namespace irr
{
namespace scene
{

//! constructor
CParticleAttractionAffector::CParticleAttractionAffector( core::vector3df point,
	f32 speed, bool attract, bool affectX, bool affectY, bool affectZ )
: Point( point )
, Speed( speed )
, AffectX( affectX )
, AffectY( affectY )
, AffectZ( affectZ )
, Attract( attract )
, LastTime( 0 )
{
}


//! Affects an array of particles.
void CParticleAttractionAffector::affect(u32 now, SParticle* particlearray, u32 count)
{
	if( LastTime == 0 )
	{
		LastTime = now;
		return;
	}

	f32 timeDelta = ( now - LastTime ) / 1000.0f;
	LastTime = now;

	if( Enabled )
	{
		for(u32 i=0; i<count; ++i)
		{
			core::vector3df direction = (Point - particlearray[i].pos).normalize();
			direction *= Speed * timeDelta;

			if( !Attract )
				direction *= -1.0f;

			if( AffectX )
				particlearray[i].pos.X += direction.X;

			if( AffectY )
				particlearray[i].pos.Y += direction.Y;

			if( AffectZ )
				particlearray[i].pos.Z += direction.Z;
		}
	}
}


} // end namespace scene
} // end namespace irr

