PreIllumSystem Class Reference

This class represents a particle system that uses the Illumination Networks technique. More...

#include <PreIllumSystem.h>

List of all members.

Public Member Functions
void	SetEyeCamera (Camera *theCam)
void	Init (int particlecount, int directioncount)
	Initializator function.
void	Display ()
	Render the particle system.
void	Refresh (Vector lightpos, Vector lightpos2, Vector lightcolor, Vector lightcolor2)
	Refreshes the system in a frame.
char *	DisplayTexture (int tex)
	Displays one of the textures used by the system.
void	getNearest (Vector *positions)
void	IncreaseOpacity ()
void	DecreaseOpacity ()
void	IncreaseAlbedo ()
void	DecreaseAlbedo ()
float	getAlbedo ()
float	getOpacity ()
void	ResetIllumTexture ()
void	setSkyColor (Vector skyC)
Public Attributes
ParticleSystem	m_System
	a system that stores particle positions and can render them as sprites
int	m_DirectionCount
	the number of directions the technique should use
int	m_ParticleCount
	the number of particles in the system
float	m_Albedo
	the albedo of one particle
float	m_Opacity
	the desirer opacity of the medium
float	m_Symmetry
	the symmetry of scattering used in the phase function
int	m_LightWindowSize
	resolution of the lightsources viewports
int	m_IterateCount
	number of iterations in a frame
Private Member Functions
void	CreateGivenDirections ()
	generates directions equally along the unit sphere
void	CreateRandomDirections (bool fillarray)
	generates random directions
void	Calculate_Up_Right_Vector (Vector viewdir, Vector &UpVector, Vector &RightVector)
float	Phase (Vector diri, Vector dirj, float symmetry)
	calculates the scattering phase function value for two directions and a symmetry value
	GetNearestDirection (Vector LightPosition)
	searches the stored directions and returns the one closest to a given direction
void	InitSystem (int particlecount, int directioncount)
	Initializator function.
void	CreateVisibilityTexture ()
	Creates a texture that stores the visibility information of the particles.
void	CreateNearestDirectionTexture ()
	Creates a texture that stores.
void	CreatePhaseTexture ()
	Creates a look-up texture to speed up phase function calculation.
void	CreateLVisMap ()
	Creates a texture that can be used to determine which particles are visible from the lightsource.
void	CreateTauTexture ()
	Creates a texture tha stores the tau value for each particle.
void	RefreshDirectIllumTexture ()
	Refreshes the texture that stores direct illumination information.
void	Iterate ()
	Updates the illumination texture.
void	CreateEyeRadTexture ()
	Updates the eye radiance texture.
void	FindVisiblesWithRendering (Vector LightPosition, int row)
	Finds the visible particles from a point of view.
void	RenderToImpostor ()
	not used
Private Attributes
Vector	m_SkyColor
	color of the sky
Impostor	m_ScreenQuad
	used for fullscreen quad rendering
Impostor	m_CameraImpostor
Impostor	m_LightImpostor
Camera *	m_EyeCamera
	view camera
Camera	m_TempCamera
Vector	m_LightPosition
	position of the first lightsource
Vector	m_LightColor
	color of the first lightsource
Vector	m_LightPosition2
	position of the second lightsource
Vector	m_LightColor2
	color of the second lightsource
int	m_NearestDir
	the closest direction from the predefined directions to the light's direction
int	m_NearestDir2
	the second closest direction from the predefined directions to the light's direction
float	m_Weight1
	weight of m_NearestDir
float	m_Weight2
	weight of m_NearestDir2
Particle *	m_ParticleArray
float *	m_PositionArray
float *	m_DirectionData
Vector *	m_Directions
float *	m_DirectionArray
unsigned char *	m_LVisMap
unsigned char *	m_LRendVisMap
float *	m_Pixels
GLuint	m_VisibilityTexID
	stores the visibility information of the particles
GLuint	m_DirectionsTexID
	stores predefined directions to use
GLuint	m_PhaseTextureID
	a look-up texture to speed up phase function calculation
GLuint	m_LVisMapID
	a texture that can be used to determine which particles are visible from the lightsource
GLuint	m_RenderedVisID
	used when determining licible particles
GLuint	m_TauTextureID
	stores tau value for each particle
CgProgram	m_TexRectPrograms
CgProgram	m_LightIllumPrograms
CgProgram	m_IllumIteratePrograms
CgProgram	m_EyeRadPrograms
CgProgram	m_LVisPrograms
CgProgram	m_FinalRenderPrograms
RenderTexture	m_DirectIlumTexture
RenderTexture	m_IllumTexture
RenderTexture	m_IllumTexture2
RenderTexture *	m_IllumColorTex
RenderTexture *	m_IllumRenderTex
RenderTexture	m_EyeRadTexture
RenderTexture	m_Target
Texture	m_BillboardTexture
Texture	m_Bbtex
RenderTexture	m_ImpostorTexture

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Detailed Description

This class represents a particle system that uses the Illumination Networks technique.

This particle system can be lit with two dinamic directional light sources and a sky light color. The direction and color of the light sources can freely change.

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Member Function Documentation

void PreIllumSystem::CreateEyeRadTexture (   )  [private]

Updates the eye radiance texture. The eye radiance texture stores the amount of light headig from each particle to the eye.

void PreIllumSystem::CreateTauTexture (   )  [private]

Creates a texture tha stores the tau value for each particle. The tau values are calculated from the given desired opacity and the size of the particle.

void PreIllumSystem::CreateVisibilityTexture (   )  [private]

Creates a texture that stores the visibility information of the particles. For each particle for each direction the first visible (from that direction) particle's id is stored.

char * PreIllumSystem::DisplayTexture (  int  tex  )

Displays one of the textures used by the system. Used for debugging and presentation.

void PreIllumSystem::FindVisiblesWithRendering (  Vector  LightPosition, int  row )  [private]

Finds the visible particles from a point of view. The light visibility texture stores the id of the visible particles (with occlusion) from the light sources. The param "row" means the id of the lightsource ( 0 or 1). The visibility is calculated with rendering the particles from the lightsource. Each particle has a color corresponding it's id. The resulting image is read back, and the pixels are counted. If the number of pixels with a particle's id found is greather than some limit, the particle is visible.

void PreIllumSystem::Refresh (  Vector  lightpos, Vector  lightpos2, Vector  lightcolor, Vector  lightcolor2 )

Refreshes the system in a frame. The actual light positions and colors should be passed.

void PreIllumSystem::RefreshDirectIllumTexture (   )  [private]

Refreshes the texture that stores direct illumination information. Direct illumination is the amount of light coming directly from the lightsource.

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Member Data Documentation

int PreIllumSystem::m_IterateCount

number of iterations in a frame As the result of the last frame is used, this should be set to one.

GLuint PreIllumSystem::m_RenderedVisID [private]

used when determining licible particles See also: FindVisiblesWithRendering

GLuint PreIllumSystem::m_VisibilityTexID [private]

stores the visibility information of the particles For each particle for each direction the first visible (from that direction) particle's id is stored.

float PreIllumSystem::m_Weight1 [private]

weight of m_NearestDir m_NearestDir and m_NearestDir2 will be interpolated

float PreIllumSystem::m_Weight2 [private]

weight of m_NearestDir2 m_NearestDir and m_NearestDir2 will be interpolated

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The documentation for this class was generated from the following files:

• PreIllumSystem.h
• PreIllumSystem.cpp

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