- Qt 5.15
- Qt 3D
- C++ Classes
- QPointLight
- Qt 5.15.11 Reference Documentation

# QPointLight Class

class Qt3DRender::QPointLight

Encapsulate a Point Light object in a Qt 3D scene. More...

Header: | #include <QPointLight>
qmake: | QT += 3drender
Since: | Qt 5.5
Instantiated By: | PointLight
Inherits: | Qt3DRender::QAbstractLight

This class was introduced in Qt 5.5.

- List of all members, including inherited members

## Properties

- constantAttenuation : float
- linearAttenuation : float
- quadraticAttenuation : float

## Public Functions

| QPointLight(Qt3DCore::QNode *parent = nullptr)
float | constantAttenuation() const
float | linearAttenuation() const
float | quadraticAttenuation() const

## Public Slots

void | setConstantAttenuation(float value)
void | setLinearAttenuation(float value)
void | setQuadraticAttenuation(float value)

## Signals

void | constantAttenuationChanged(float constantAttenuation)
void | linearAttenuationChanged(float linearAttenuation)
void | quadraticAttenuationChanged(float quadraticAttenuation)

## Detailed Description

A point light is a light source that emits light in all directions, from a single point. Conceptually, this is similar to light given off by a standard light bulb.

A point light uses three attenuation factors to describe how the intensity of the light decreases over distance. These factors are designed to be used together in calcuating total attenuation. For the materials in Qt3D Extras the following formula is used, where distance is the distance from the light to the surface being rendered:

     totalAttenuation = 1.0 / (constantAttenuation + (linearAttenuation * distance) + (quadraticAttenuation * distance * distance));

Custom materials may choose to interpret these factors differently.

## Property Documentation

### constantAttenuation : float

Specifies the constant attenuation of the point light.

Note: The exact meaning and use of this property is up to the material implementation.

Access functions:

float | constantAttenuation() const
void | setConstantAttenuation(float value)

Notifier signal:

void | constantAttenuationChanged(float constantAttenuation)

### linearAttenuation : float

Specifies the linear attenuation of the point light.

Note: The exact meaning and use of this property is up to the material implementation.

Access functions:

float | linearAttenuation() const
void | setLinearAttenuation(float value)

Notifier signal:

void | linearAttenuationChanged(float linearAttenuation)

### quadraticAttenuation : float

Specifies the quadratic attenuation of the point light.

Note: The exact meaning and use of this property is up to the material implementation.

Access functions:

float | quadraticAttenuation() const
void | setQuadraticAttenuation(float value)

Notifier signal:

void | quadraticAttenuationChanged(float quadraticAttenuation)

## Member Function Documentation

### QPointLight::QPointLight(Qt3DCore::QNode *parent = nullptr)

Constructs a new QPointLight with the specified parent.