// 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 "CParticleBoxEmitter.h"
#include "os.h"
#include "IAttributes.h"
#include "irrMath.h"

namespace irr
{
namespace scene
{

//! constructor
CParticleBoxEmitter::CParticleBoxEmitter(
	const core::aabbox3df& box,
	const core::vector3df& direction, u32 minParticlesPerSecond,
	u32 maxParticlesPerSecond,	video::SColor minStartColor,
	video::SColor maxStartColor, u32 lifeTimeMin, u32 lifeTimeMax,
	s32 maxAngleDegrees)
 : Box(box), Direction(direction), MinParticlesPerSecond(minParticlesPerSecond),
	MaxParticlesPerSecond(maxParticlesPerSecond),
	MinStartColor(minStartColor), MaxStartColor(maxStartColor),
	MinLifeTime(lifeTimeMin), MaxLifeTime(lifeTimeMax), Time(0), Emitted(0),
	MaxAngleDegrees(maxAngleDegrees)
{
}



//! Prepares an array with new particles to emitt into the system
//! and returns how much new particles there are.
s32 CParticleBoxEmitter::emitt(u32 now, u32 timeSinceLastCall, SParticle*& outArray)
{
	Time += timeSinceLastCall;

	u32 pps = (MaxParticlesPerSecond - MinParticlesPerSecond);
	f32 perSecond = pps ? (f32)MinParticlesPerSecond + (os::Randomizer::rand() % pps) : MinParticlesPerSecond;
	f32 everyWhatMillisecond = 1000.0f / perSecond;

	if (Time > everyWhatMillisecond)
	{
		Particles.set_used(0);
		u32 amount = (u32)((Time / everyWhatMillisecond) + 0.5f);
		Time = 0;
		SParticle p;
		const core::vector3df& extent = Box.getExtent();

		if (amount > MaxParticlesPerSecond*2)
			amount = MaxParticlesPerSecond * 2;

		for (u32 i=0; i<amount; ++i)
		{
			p.pos.X = Box.MinEdge.X + fmodf((f32)os::Randomizer::rand(), extent.X);
			p.pos.Y = Box.MinEdge.Y + fmodf((f32)os::Randomizer::rand(), extent.Y);
			p.pos.Z = Box.MinEdge.Z + fmodf((f32)os::Randomizer::rand(), extent.Z);

			p.startTime = now;
			p.vector = Direction;

			if (MaxAngleDegrees)
			{
				core::vector3df tgt = Direction;
				tgt.rotateXYBy((os::Randomizer::rand()%(MaxAngleDegrees*2)) - MaxAngleDegrees, core::vector3df());
				tgt.rotateYZBy((os::Randomizer::rand()%(MaxAngleDegrees*2)) - MaxAngleDegrees, core::vector3df());
				tgt.rotateXZBy((os::Randomizer::rand()%(MaxAngleDegrees*2)) - MaxAngleDegrees, core::vector3df());
				p.vector = tgt;
			}

			if (MaxLifeTime - MinLifeTime == 0)
				p.endTime = now + MinLifeTime;
			else
				p.endTime = now + MinLifeTime + (os::Randomizer::rand() % (MaxLifeTime - MinLifeTime));

			p.color = MinStartColor.getInterpolated(
				MaxStartColor, (os::Randomizer::rand() % 100) / 100.0f);

			p.startColor = p.color;
			p.startVector = p.vector;

			Particles.push_back(p);
		}

		outArray = Particles.pointer();

		return Particles.size();
	}

	return 0;
}


//! Writes attributes of the object.
void CParticleBoxEmitter::serializeAttributes(io::IAttributes* out, io::SAttributeReadWriteOptions* options) const
{
	core::vector3df b = Box.getExtent();
	b *= 0.5f;
	out->addVector3d("Box", b);
	out->addVector3d("Direction", Direction);
	out->addInt("MinParticlesPerSecond", MinParticlesPerSecond);
	out->addInt("MaxParticlesPerSecond", MaxParticlesPerSecond);
	out->addColor("MinStartColor", MinStartColor);
	out->addColor("MaxStartColor", MaxStartColor);
	out->addInt("MinLifeTime", MinLifeTime);
	out->addInt("MaxLifeTime", MaxLifeTime);
	out->addInt("MaxAngleDegrees", MaxAngleDegrees);
}


//! Reads attributes of the object.
s32 CParticleBoxEmitter::deserializeAttributes(s32 startIndex, io::IAttributes* in, io::SAttributeReadWriteOptions* options)
{
	// read data and correct input values here

	core::vector3df b = in->getAttributeAsVector3d("Box");

	if (b.X <= 0)
		b.X = 1.0f;
	if (b.Y <= 0)
		b.Y = 1.0f;
	if (b.Z <= 0)
		b.Z = 1.0f;

	Box.MinEdge.X = -b.X;
	Box.MinEdge.Y = -b.Y;
	Box.MinEdge.Z = -b.Z;
	Box.MaxEdge.X = b.X;
	Box.MaxEdge.Y = b.Y;
	Box.MaxEdge.Z = b.Z;

	Direction = in->getAttributeAsVector3d("Direction");
	if (Direction.getLength() == 0)
		Direction.set(0,0.01f,0);

	MinParticlesPerSecond = in->getAttributeAsInt("MinParticlesPerSecond");
	MaxParticlesPerSecond = in->getAttributeAsInt("MaxParticlesPerSecond");

	MinParticlesPerSecond = core::max_(1u, MinParticlesPerSecond);
	MaxParticlesPerSecond = core::max_(MaxParticlesPerSecond, 1u);
	MaxParticlesPerSecond = core::min_(MaxParticlesPerSecond, 200u);
	MinParticlesPerSecond = core::min_(MinParticlesPerSecond, MaxParticlesPerSecond);

	MinStartColor = in->getAttributeAsColor("MinStartColor");
	MaxStartColor = in->getAttributeAsColor("MaxStartColor");
	MinLifeTime = in->getAttributeAsInt("MinLifeTime");
	MaxLifeTime = in->getAttributeAsInt("MaxLifeTime");
	MaxAngleDegrees = in->getAttributeAsInt("MaxAngleDegrees");

	MinLifeTime = core::max_(0u, MinLifeTime);
	MaxLifeTime = core::max_(MaxLifeTime, MinLifeTime);
	MinLifeTime = core::min_(MinLifeTime, MaxLifeTime);

	return in->findAttribute("MaxAngleDegrees");
}


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

