proland::ScreenParticleLayer Class Reference
[screen]

A ParticleLayer to force particles to stay in the viewport, with a uniform density. More...

#include <ScreenParticleLayer.h>

Inheritance diagram for proland::ScreenParticleLayer:

Classes
struct	ScreenParticle
	Layer specific particle data for managing particles in screen space. More...
Public Types
enum	status { AGE, OUTSIDE_VIEWPORT, POISSON_DISK }
	The reason why a particle is fading out. More...
Public Member Functions
	ScreenParticleLayer (float radius, ptr< Texture2D > offscreenDepthBuffer)
	Creates a new ScreenParticleLayer.
virtual	~ScreenParticleLayer ()
	Deletes this LifeCycleParticleLayer.
float	getParticleRadius () const
	Returns the Poisson-disk radius of each particle, in pixels.
void	setParticleRadius (float radius)
	Sets the Poisson-disk radius of each particle, in pixels.
ScreenParticle *	getScreenParticle (ParticleStorage::Particle *p)
	Returns the screen space specific data of the given particle.
void	setSceneManager (SceneManager *manager)
	Sets the scene manager used to set the world to screen transformation.
virtual void	moveParticles (double dt)
	Moves the existing particles.
virtual void	removeOldParticles ()
	Removes old particles.
virtual void	addNewParticles ()
	Adds new particles.
ScreenParticle **	getNeighbors (ScreenParticle *s, int &n)
	Returns the neighbors of the given screen particle.
Protected Member Functions
	ScreenParticleLayer ()
	Creates an uninitialized ScreenParticleLayer.
void	init (float radius, ptr< Texture2D > offscreenDepthBuffer)
	Initializes this ScreenParticleLayer.
virtual void	initialize ()
	Initializes this ParticleLayer.
virtual void	initParticle (ParticleStorage::Particle *p)
	Initializes the data that is specific to this layer in the given particle.
Private Member Functions
void	findNeighborRanges (ScreenParticle *p)
	Updates ranges based on the neighbors of the given particle.
ScreenParticle *	newScreenParticle (const vec2f &pos)
	Creates a new particle at the given position, and adds it to grid.
void	getParticleDepths (const vector< ScreenParticle * > &particles)
	Reads the depths of the given particles from the depth buffer.
Private Attributes
SceneManager *	scene
	The scene manager, used to get the world to screen transformation.
float	radius
	The Poisson-disk radius of each particle, in pixels.
box2f	bounds
	The current bounds of the viewport, in pixels.
ParticleGrid *	grid
	A ParticleGrid to store particles according to their screen position.
RangeList *	ranges
	Data structure used to find where to create new particles, so that they form a Poisson-disk distribution.
mat4d	lastWorldToScreen
	The world to screen transformation of the last frame.
vec4i	lastViewport
	The viewport of the last frame.
bool	depthBufferRead
	True if the camera is not moving, and if the depth buffer has been read into depthArray.
int	depthArraySize
	The size of the depthArray array.
float *	depthArray
	Array used to get the depth of the particles created at this frame or the depth of all the pixels of the depth buffer.
ptr< FrameBuffer >	frameBuffer
	Framebuffer in which to execute the packer program.
ptr< Mesh< vec3f, unsigned int > >	mesh
	Mesh used to retrieve depths with the packer program.
ptr< UniformSampler >	depthTextureU
	Sampler uniform to access the depthTexture texture.
ptr< Uniform3f >	sizeU
	Viewport width and height, plus width of the framebuffer viewport.
bool	useOffscreenDepthBuffer
	True if the user provides an offscreen depthbuffer.
WorldParticleLayer *	worldLayer
	The layer managing the particles in world space.
LifeCycleParticleLayer *	lifeCycleLayer
	The layer managing the particles life cycle.
Static Private Attributes
static static_ptr< Program >	packer
	Program used to get the depths of a set of particles.
static static_ptr< Texture2D >	depthBuffer
	A copy of the depth buffer in the form of a texture.

Detailed Description

A ParticleLayer to force particles to stay in the viewport, with a uniform density.

This layer requires particles initially managed in world space, using a WorldParticleLayer. It then forces these particles to stay in the framebuffer viewport. For that it deletes particles that project outside the viewport, and creates new particles in this viewport to maintain a constant density of particles. In fact particles are not really deleted, but forced to fading out. This requires a LifeCycleParticleLayer.

Author:: Antoine Begault, Guillaume Piolat

Member Enumeration Documentation

enum proland::ScreenParticleLayer::status

The reason why a particle is fading out.

Enumerator:

AGE	the particle reached its maximum age
OUTSIDE_VIEWPORT	the particle projected outside the viewport
POISSON_DISK	the particle was too close to other particles

Constructor & Destructor Documentation

proland::ScreenParticleLayer::ScreenParticleLayer	(	float	radius,
		ptr< Texture2D >	offscreenDepthBuffer
	)

Creates a new ScreenParticleLayer.

Parameters:

	radius	the radius of each particle, in pixels. This radius is used as a Poisson-disk radius for maintaining a Poisson distribution of particles in screen space.
	offscreenDepthBuffer	the offscreen buffer that contains depth. This texture is used to avoid copying the depth buffer at each frame.

virtual proland::ScreenParticleLayer::~ScreenParticleLayer ( ) [virtual]

Deletes this LifeCycleParticleLayer.

proland::ScreenParticleLayer::ScreenParticleLayer ( ) [protected]

Creates an uninitialized ScreenParticleLayer.

Member Function Documentation

virtual void proland::ScreenParticleLayer::addNewParticles ( ) [virtual]

Adds new particles.

The default implementation of this method does nothing.

Reimplemented from proland::ParticleLayer.

void proland::ScreenParticleLayer::findNeighborRanges ( ScreenParticle * p ) [private]

Updates ranges based on the neighbors of the given particle.

ScreenParticle** proland::ScreenParticleLayer::getNeighbors	(	ScreenParticle *	s,
		int &	n
	)

Returns the neighbors of the given screen particle.

Parameters:

	s	a screen particle.
`[out]`	n	the number of neighbors of s.

Returns:: the neighbors of s.

void proland::ScreenParticleLayer::getParticleDepths ( const vector< ScreenParticle * > & particles ) [private]

Reads the depths of the given particles from the depth buffer.

Parameters:

particles

a list of particles.

float proland::ScreenParticleLayer::getParticleRadius ( ) const

Returns the Poisson-disk radius of each particle, in pixels.

ScreenParticle* proland::ScreenParticleLayer::getScreenParticle ( ParticleStorage::Particle * p ) [inline]

Returns the screen space specific data of the given particle.

Parameters:

p

a particle.

void proland::ScreenParticleLayer::init	(	float	radius,
		ptr< Texture2D >	offscreenDepthBuffer
	)			`[protected]`

Initializes this ScreenParticleLayer.

See ScreenParticleLayer.

virtual void proland::ScreenParticleLayer::initialize ( ) [protected, virtual]

Initializes this ParticleLayer.

If this layer needs reference to other layers it can initialize them in this method (using the template method ParticleProducer::getLayer()). The default implementation of this method does nothing.

Reimplemented from proland::ParticleLayer.

virtual void proland::ScreenParticleLayer::initParticle ( ParticleStorage::Particle * p ) [protected, virtual]

Initializes the data that is specific to this layer in the given particle.

The default implementation of this method does nothing.

Reimplemented from proland::ParticleLayer.

virtual void proland::ScreenParticleLayer::moveParticles ( double dt ) [virtual]

Moves the existing particles.

The default implementation of this method does nothing.

Parameters:

dt

the elapsed time since the last call to this method, in microseconds.

Reimplemented from proland::ParticleLayer.

ScreenParticle* proland::ScreenParticleLayer::newScreenParticle ( const vec2f & pos ) [private]

Creates a new particle at the given position, and adds it to grid.

Parameters:

pos

a position in screen space, in pixels.

Returns:: the created particle, or NULL if the maximum capacity of the particles storage was reached.

virtual void proland::ScreenParticleLayer::removeOldParticles ( ) [virtual]

Removes old particles.

The default implementation of this method does nothing.

Reimplemented from proland::ParticleLayer.

void proland::ScreenParticleLayer::setParticleRadius ( float radius )

Sets the Poisson-disk radius of each particle, in pixels.

void proland::ScreenParticleLayer::setSceneManager ( SceneManager * manager )

Sets the scene manager used to set the world to screen transformation.

Member Data Documentation

box2f proland::ScreenParticleLayer::bounds [private]

The current bounds of the viewport, in pixels.

Particles are forced to stay in this viewport by this particle layer.

float* proland::ScreenParticleLayer::depthArray [private]

Array used to get the depth of the particles created at this frame or the depth of all the pixels of the depth buffer.

int proland::ScreenParticleLayer::depthArraySize [private]

The size of the depthArray array.

static_ptr<Texture2D> proland::ScreenParticleLayer::depthBuffer [static, private]

A copy of the depth buffer in the form of a texture.

This texture is needed by the packer program to access the depth of arbitrary pixels in the depth buffer.

bool proland::ScreenParticleLayer::depthBufferRead [private]

True if the camera is not moving, and if the depth buffer has been read into depthArray.

ptr<UniformSampler> proland::ScreenParticleLayer::depthTextureU [private]

Sampler uniform to access the depthTexture texture.

ptr<FrameBuffer> proland::ScreenParticleLayer::frameBuffer [private]

Framebuffer in which to execute the packer program.

This framebuffer uses as color attachment a texture containing the depths read by packer, which are then read back in depthArray.

ParticleGrid* proland::ScreenParticleLayer::grid [private]

A ParticleGrid to store particles according to their screen position.

This grid is necessary to quickly find the neighbors of particles, which are themselves needed to maintain a Poisson-disk distribution.

vec4i proland::ScreenParticleLayer::lastViewport [private]

The viewport of the last frame.

Used to determine if the camera moved at this frame.

mat4d proland::ScreenParticleLayer::lastWorldToScreen [private]

The world to screen transformation of the last frame.

Used to determine if the camera moved at this frame.

LifeCycleParticleLayer* proland::ScreenParticleLayer::lifeCycleLayer [private]

The layer managing the particles life cycle.

ptr< Mesh<vec3f, unsigned int> > proland::ScreenParticleLayer::mesh [private]

Mesh used to retrieve depths with the packer program.

This point mesh contains one point per particle. Each point contains the screen coordinates of a particle, and the index of this particle.

static_ptr<Program> proland::ScreenParticleLayer::packer [static, private]

Program used to get the depths of a set of particles.

float proland::ScreenParticleLayer::radius [private]

The Poisson-disk radius of each particle, in pixels.

RangeList* proland::ScreenParticleLayer::ranges [private]

Data structure used to find where to create new particles, so that they form a Poisson-disk distribution.

SceneManager* proland::ScreenParticleLayer::scene [private]

The scene manager, used to get the world to screen transformation.

ptr<Uniform3f> proland::ScreenParticleLayer::sizeU [private]

Viewport width and height, plus width of the framebuffer viewport.

bool proland::ScreenParticleLayer::useOffscreenDepthBuffer [private]

True if the user provides an offscreen depthbuffer.

This allows to not copy the depthbuffer before reading from it.

WorldParticleLayer* proland::ScreenParticleLayer::worldLayer [private]

The layer managing the particles in world space.

proland::ScreenParticleLayer Class Reference [screen]

Classes

Public Types

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Static Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

proland::ScreenParticleLayer Class Reference
[screen]