An Actor that draws and keeps track of drawing a particle system on screen. More...

#include <ParticleActor.h>

Inheritance diagram for ParticleActor:

Public Member Functions
	ParticleActor ()
	~ParticleActor ()
virtual void	Update (float dt)
virtual void	Render ()
void	SetParticlesPerSecond (float pps)
void	SetSystemLifetime (float lifetime)
void	SetParticleLifetime (float lifetime)
void	SetSpread (float radians)
void	SetEndScale (float scale)
void	SetEndColor (Color &color)
void	SetSpeedRange (float minSpeed, float maxSpeed)
void	SetMinSpeed (float minSpeed)
void	SetMaxSpeed (float maxSpeed)
void	SetGravity (Vector2 &gravity)
void	SetMaxParticles (int maxParticles)
virtual const String	GetClassName ()
Protected Attributes
Particle *	_particles
int	_maxParticlesAlive
int	_numParticlesAlive
float	_particlesPerSecond
int	_maxParticlesToGenerate
float	_generationResidue
float	_systemLifetime
float	_particleLifetime
float	_spreadRadians
Color	_endColor
float	_minSpeed
float	_maxSpeed
float	_endScale
Vector2	_gravity
Friends
class	ParticleActorFactoryDelegate

Detailed Description

Particle systems are a very common feature of most games -- they can be used for effects like fire, smoke, sparklies, etc. A discussion of the general use of particles is beyond the scope of this documentation, but if you're not familiar with the concept, this article by Jeff Lander is a good starting point.

http://www.double.co.nz/dust/col0798.pdf

Definition at line 57 of file ParticleActor.h.

Constructor & Destructor Documentation

ParticleActor::ParticleActor ( )

The default constructor creates a particle system that doesn't really do anything, since its maximum number of particles is 0. You'll need to call the "Set" functions below to make it look purty.

Definition at line 35 of file ParticleActor.cpp.

ParticleActor::~ParticleActor ( )

Deletes all the particles this Actor is keeping track of.

Definition at line 60 of file ParticleActor.cpp.

Member Function Documentation

void ParticleActor::Update ( float dt ) [virtual]

Override of the normal Renderable::Update function. Changes the position and appearance of each individual particle appropriately.

Parameters:

dt	The amount of time that's elapsed since the beginning of the last frame.

Reimplemented from Actor.

Definition at line 65 of file ParticleActor.cpp.

void ParticleActor::Render ( ) [virtual]

Override of the normal Renderable::Render function. Draws each particle.

Reimplemented from Actor.

Definition at line 174 of file ParticleActor.cpp.

void ParticleActor::SetParticlesPerSecond ( float pps )

Change the rate at which this system releases particles. Default is 20 particles per second.

Parameters:

pps	The new release rate in particles per second.

Definition at line 232 of file ParticleActor.cpp.

void ParticleActor::SetSystemLifetime ( float lifetime )

Change the system lifetime for this Actor. If the lifetime is set less than or equal to 0.0 (the default), the system will last until it's explicitly removed from the world. Otherwise the system will properly remove and deallocate itself when the elapsed time is up. (Useful for when you just want a burst of particles for a period of time and don't want to set up housekeeping timer.)

Parameters:

lifetime The amount of time this system will persist, in seconds.

Definition at line 241 of file ParticleActor.cpp.

void ParticleActor::SetParticleLifetime ( float lifetime )

Change the lifetime of each individual particle.

Parameters:

lifetime Particle lifetime in seconds

Definition at line 250 of file ParticleActor.cpp.

void ParticleActor::SetSpread ( float radians )

Set the angle at which particles will disperse themselves. This affects their intial velocity only. Default is 0.0 (straight line to the right).

Parameters:

radians Emission angle in radians

Definition at line 259 of file ParticleActor.cpp.

void ParticleActor::SetEndScale ( float scale )

Set the relative size each particle will grow (or shrink) to over its lifetime. The starting size is set with the normal Actor::SetSize function. The ending scale respects the starting aspect ratio.

Parameters:

scale The multiplier gradually applied to each particle

Definition at line 264 of file ParticleActor.cpp.

void ParticleActor::SetEndColor ( Color & color )

Set the color each particle should be at the end of its life. Use an alpha of 0.0 to have the particles fade out over time. Starting color is set with the normal Actor::SetColor function.

Parameters:

color The ending color for each particle in the system.

Definition at line 269 of file ParticleActor.cpp.

void ParticleActor::SetSpeedRange	(	float	minSpeed,
		float	maxSpeed
	)

Set the range of potential initial speeds for the particles. Each particle, at the start of its life, will randomly pick a speed in the given range.

Parameters:

minSpeed	The speed (in GL units per second) of the slowest particle
maxSpeed	The speed (in GL units per second) of the fastest particle

Definition at line 274 of file ParticleActor.cpp.

void ParticleActor::SetMinSpeed ( float minSpeed )

Set the lower range of potential initial speeds for the particles.

Parameters:

minSpeed The speed (in GL units per second) of the slowest particle

Definition at line 280 of file ParticleActor.cpp.

void ParticleActor::SetMaxSpeed ( float maxSpeed )

Set the lower range of potential initial speeds for the particles.

Parameters:

maxSpeed The speed (in GL units per second) of the fastest particle

Definition at line 285 of file ParticleActor.cpp.

void ParticleActor::SetGravity ( Vector2 & gravity )

Set the vector which will pull the particles in a specific direction at a specified magnitude. The default is (0.0, -4.0).

Parameters:

gravity The vector in which the particles should be pulled (magnitude affecting the force of the pull).

Definition at line 290 of file ParticleActor.cpp.

void ParticleActor::SetMaxParticles ( int maxParticles )

Set the maximum number of particles this system can keep track of at any one time. Decrease this number if you find you're having performance issues with your particles.

Parameters:

maxParticles The maximum number of particles for this system.

Definition at line 295 of file ParticleActor.cpp.

virtual const String ParticleActor::GetClassName ( ) [inline, virtual]

Used by the SetName function to create a basename for this class. Overridden from Actor::GetClassName.