SpotLight Class Reference

Defines a spot light which is a source at specific position with edge fall-off and attentuation. More...

#include <Rendering/SceneComponents/Lights/spotlight.h>

Inheritance diagram for SpotLight:

Public Member Functions
	SpotLight ()
	SpotLight (const SpotLight &light)
	~SpotLight () override
void	clearAttenuationFactors ()
SpotLight *	clone () const override
double	getAttenuationFactor (unsigned power) const
double	getCutoffAngle () const
double	getEdgeFalloff () const
double	getFadeAngle () const
unsigned	numAttenuationFactors () const
SpotLight &	operator= (const SpotLight &light)
void	setAttenuationFactor (unsigned power, double factor)
void	setCutoffAngle (double angle)
void	setEdgeFalloff (double f)
void	setFadeAngle (double angle)
bool	visit (LightsProcessor &processor) override
Public Member Functions inherited from Light
	Light (const QString &id="")
	~Light () override
Light *	clone () const override=0
const QColor &	getColor () const
double	getIntensity () const
Mesh::Vector3d	getOrientation () const
Mesh::Vector3d	getPosition () const
void	setColor (const QColor &color)
void	setIntensity (double d)
virtual bool	visit (LightsProcessor &processor)=0
bool	visit (SceneProcessor &processor) override
Public Member Functions inherited from SceneItem
	~SceneItem () override
SceneItem *	clone () const override=0
bool	getEnabled () const
const QString &	getId () const
const Mesh::BoundingBoxMinimal &	getLocalBoundingBox () const
virtual Mesh::TransformMatrix	getMatrixGlobal () const
virtual Mesh::TransformMatrix	getMatrixLocal () const
const QString &	getName () const
Mesh::TransformMatrix	getParentMatrixGlobal () const
Transform *	getParentTransform ()
void	setEnabled (bool b)
void	setId (const QString &itemId)
virtual void	setLocalBoundingBox (const Mesh::BoundingBoxMinimal &bb)
void	setName (const QString &name)
virtual Transform *	toTransform ()
virtual const Transform *	toTransform () const
virtual void	updateGlobalMatrix ()
virtual bool	visit (SceneProcessor &processor)=0
Public Member Functions inherited from Observable
virtual	~Observable ()
void	attachObserver (Observer &observer)
void	destroy ()
void	detachObserver (Observer &observer)
void	notifyEvent (const ObservableEvent &event)
Public Member Functions inherited from Clonable
virtual	~Clonable ()=default
virtual Clonable *	clone () const =0

Additional Inherited Members
Protected Member Functions inherited from Light
	Light (const Light &light)
Light &	operator= (const Light &light)
Protected Member Functions inherited from SceneItem
	SceneItem (const QString &id)
	SceneItem (const SceneItem &item)
virtual void	addToScene (Scene &scene, const QString &opIdPath="")
bool	isTransformModified () const
SceneItem &	operator= (const SceneItem &item)
void	setTransformModified (bool b)
Protected Member Functions inherited from Observable
	Observable ()
	Observable (const Observable &)

Detailed Description

Spot lights do support attenuation and edge fall-off. These characteristics can be modified to yield different spot light effects and can be used to generate a reasonably good approximation to a real spot light. This is more complex to set up than a DirectionalLight.

Constructor & Destructor Documentation

SpotLight() [1/2]

SpotLight

(

)

SpotLight() [2/2]

SpotLight

(

const SpotLight &

light

)

~SpotLight()

~SpotLight ( )

override

Member Function Documentation

clearAttenuationFactors()

void clearAttenuationFactors

(

)

Clears all the attenuation factors. This will result in a light with no attenuation with distance from the light source.

See also

setAttenuationFactors(), numAttenuationFactors()

clone()

SpotLight * clone ( ) const

overridevirtual

Returns

A clone of this item.

Subclasses must reimplement this function to return a clone of themselves.

Implements Light.

getAttenuationFactor()

double getAttenuationFactor

(

unsigned

power

)

const

Parameters

power

The power of the factor to retrieve.

Returns

The factor being applied to the specified power. If no factor has been set for this power, a value of zero will be returned.

getCutoffAngle()

double getCutoffAngle

(

)

const

Returns

The cutoff angle in degrees.

See also

setCutoffAngle()

getEdgeFalloff()

double getEdgeFalloff

(

)

const

Returns

The edge fall-off of the light.

See also

setEdgeFalloff()

getFadeAngle()

double getFadeAngle

(

)

const

Returns

The angle at which the lights intensity will start to fade (relative to its direction.

See also

setFadeAngle

numAttenuationFactors()

unsigned numAttenuationFactors

(

)

const

Returns

The number of attenuation factors set for this light.

See also

setAttenuationFactors()

operator=()

SpotLight & operator=

(

const SpotLight &

light

)

setAttenuationFactor()

void setAttenuationFactor	(	unsigned	power,
		double	factor
	)

Parameters

power	The integer power whose factor will be set. If this is beyond the end of the current set of factors (ie if power is greater or equal to the result from numAttenuationFactors()), the factors will be zero-filled to extend them up to the specified power.
factor	The factor to apply to the power attenuation factor.

The attentuation factors correspond to integer powers starting with a power of zero. The factors may be interpretted differently by different renderers, so ensure you understand how they will be used when setting them. Most renderers will have a fairly small limit on the number of supported powers, but it would normally be safe to assume that up to at least a power of 2 would be supported (this is the limit OpenGL specifies, for example).

setCutoffAngle()

void setCutoffAngle

(

double

angle

)

Parameters

angle

The maximum spread angle (in degrees) of the light. This controls the cone angle of the light. It must be non-negative and would normally not exceed 180. Some renderers will treat angles beyond 180 with special meaning (eg the OpenGL fixed function pipeline treats an angle of 180 as giving uniform light distribution and it rejects all other values greater than 90).

See also

getCutoffAngle(), setFalloff(), setFadeAngle()

setEdgeFalloff()

void setEdgeFalloff

(

double

f

)

Parameters

f	The edge fall-off to use for the light. It must be non-negative. If it is not, the function leaves the fall-off at its old value.

The edge fall-off of a light controls how focused it is. The higher the value, the more tightly focused the light should appear. An edge fall-off of zero results in a uniform light distribution within the cone of the light and a sharp edge.

Note

Some scene renderers will have limits on how high the fall-off can be. For example, OpenGL stipulates that the fall-off (which it calls the "exponent") must be in the range [0,128].

See also

getEdgeFalloff(), setCutoffAngle()

setFadeAngle()

void setFadeAngle

(

double

angle

)

Parameters

angle

The angle from the light's direction at which its intensity will start to fade. Must be smaller than or equal to the cutoff angle. Some renderers will ignore this angle altogether and only use the cutoff angle.

See also

getFadeAngle(), setFalloff(), setFadeAngle()

visit()

bool visit ( LightsProcessor &  processor )

overridevirtual

Parameters

processor

The light processor visiting this light.

Light subclasses should reimplement this function to call processor.visit() and return the result of that call. This is the usual visitor pattern as used for other scene items and model processors.

Implements Light.