org.j3d.aviatrix3d
Class SpotLight

java.lang.Object
  org.j3d.aviatrix3d.SceneGraphObject
      org.j3d.aviatrix3d.Node
          org.j3d.aviatrix3d.Leaf
              org.j3d.aviatrix3d.Light
                  org.j3d.aviatrix3d.SpotLight

All Implemented Interfaces:

java.lang.Comparable, CascadeRenderable, ComponentRenderable, Cullable, EffectRenderable, LeafCullable, Renderable

public class SpotLight
extends Light

Representation of a spot light source.

A spot light has a direction, location and directs light as a conical shape in the given direction. Within the spotlight, there's a maximum angle that the light is effective to, and a drop-off rate of the light from the center to the maximum angle.

Internationalisation Resource Names

• angleRangeMsg: Error message when spot angle is not [0,90] deg
• negExponentMsg: Error message when falloff exponent given is negative

Version:

$Revision: 1.23 $

Author:

Justin Couch

Field Summary

Fields inherited from class org.j3d.aviatrix3d.Light

AMBIENT_TYPE, ambientColor, diffuseColor, DIRECTIONAL_TYPE, effectBounds, enabled, globalOnly, INVALID_ALPHA_PROP, INVALID_BLUE_PROP, INVALID_GREEN_PROP, INVALID_RED_PROP, POINT_TYPE, specularColor, SPOT_TYPE

Fields inherited from class org.j3d.aviatrix3d.Node

bounds, implicitBounds, INVALID_BOUNDS, parent

Fields inherited from class org.j3d.aviatrix3d.SceneGraphObject

alive, LISTENER_SET_TIMING_ERR_PROP, updateHandler

Fields inherited from interface org.j3d.aviatrix3d.rendering.LeafCullable

AUDIO_CULLABLE, CLIP_CULLABLE, FOG_CULLABLE, GEOMETRY_CULLABLE, LIGHT_CULLABLE, OVERRIDE_CULLABLE

Constructor Summary

SpotLight()
Creates a light with the colour set to black.

SpotLight(float[] col)
Create a light with the given base colour.Colour must be in the range [0, 1] otherwise an exception is generated.

SpotLight(float[] col, float[] pos, float[] dir)
Create a light with the given base colour.Colour must be in the range [0, 1] otherwise an exception is generated.

Method Summary

int	compareTo(Light l) Compares this object with the specified object for order.
void	getAttenuation(float[] values) Set the attenuation factors for the light.
float	getCutOffAngle() Get the current gut-off angle.
void	getDirection(float[] dir) Retrieve the current direction vector from the light.
float	getDropOffRateExponent() Get the current drop off exponent rate.
void	getPosition(float[] pos) Retrieve the current position vector from the light.
void	postRender(javax.media.opengl.GL gl, java.lang.Object lightId)
void	render(javax.media.opengl.GL gl, java.lang.Object lightId) Overloaded form of the render() method to render the light details given the specific Light ID used by OpenGL.
void	setAttenuation(float[] values) Set the attenuation factors for the light.
void	setAttenuation(float constant, float linear, float quad) Set the attenuation factors for the light.
void	setCutOffAngle(float angle) Set the cut-off angle.
void	setDirection(float[] dir) Set the direction to the new value.
void	setDirection(float x, float y, float z) Set the direction to the new value.
void	setDropOffRateExponent(float exp) Set the value of the exponent that can be used to control how the light intensity drops off from the center to the cut off angle.
void	setPosition(float[] pos) Set the position to the new value.
void	setPosition(float x, float y, float z) Set the position to the new value.

Methods inherited from class org.j3d.aviatrix3d.Light

compareColor3, compareTo, getAmbientColor, getCullableType, getDiffuseColor, getEffectBounds, getRenderable, getSpecularColor, isEnabled, isGlobalOnly, setAmbientColor, setDiffuseColor, setEffectBounds, setEnabled, setGlobalOnly, setSpecularColor

Methods inherited from class org.j3d.aviatrix3d.Node

boundsChanged, checkForCyclicParent, getBounds, getParent, markBoundsDirty, recomputeBounds, removeParent, requestBoundsUpdate, setBounds, setParent, updateBounds, updateParentBounds

Methods inherited from class org.j3d.aviatrix3d.SceneGraphObject

checkForCyclicChild, dataChanged, getAppUpdateWriteTimingMessage, getBoundsWriteTimingMessage, getDataWriteTimingMessage, getUserData, isLive, setLive, setUpdateHandler, setUserData

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.j3d.aviatrix3d.rendering.LeafCullable

getBounds

Methods inherited from interface org.j3d.aviatrix3d.rendering.Renderable

equals

Constructor Detail

SpotLight

public SpotLight()

Creates a light with the colour set to black.

SpotLight

public SpotLight(float[] col)
          throws java.lang.IllegalArgumentException

Create a light with the given base colour.Colour must be in the range [0, 1] otherwise an exception is generated.

Parameters:

col - The new colour value to use

Throws:

java.lang.IllegalArgumentException

SpotLight

public SpotLight(float[] col,
                 float[] pos,
                 float[] dir)
          throws java.lang.IllegalArgumentException

Create a light with the given base colour.Colour must be in the range [0, 1] otherwise an exception is generated.

Parameters:

col - The new colour value to use

dir - The direction of the light

Throws:

java.lang.IllegalArgumentException

Method Detail

render

public void render(javax.media.opengl.GL gl,
                   java.lang.Object lightId)

Overloaded form of the render() method to render the light details given the specific Light ID used by OpenGL. Since the active light ID for this node may vary over time, a fixed ID cannot be used by OpenGL. The renderer will always call this method rather than the normal render() method. The normal post render will still be called

Parameters:

gl - The GL context to render with

lightId - the ID of the light to make GL calls with

postRender

public void postRender(javax.media.opengl.GL gl,
                       java.lang.Object lightId)

setCutOffAngle

public void setCutOffAngle(float angle)
                    throws java.lang.IllegalArgumentException,
                           InvalidWriteTimingException

Set the cut-off angle. The angle must lie in the range [0, 90] degrees. Although OpenGL allows the special value of 180 to be used, that functions just like a pointlight, so use that class instead.

Parameters:

angle - The angle in degrees [0, 90]

Throws:

java.lang.IllegalArgumentException - The angle was outside the range

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getCutOffAngle

public float getCutOffAngle()

Get the current gut-off angle. The angle will lie in the range [0, 90] degrees.

Returns:

The angle in degrees [0, 90]

setDropOffRateExponent

public void setDropOffRateExponent(float exp)
                            throws java.lang.IllegalArgumentException,
                                   InvalidWriteTimingException

Set the value of the exponent that can be used to control how the light intensity drops off from the center to the cut off angle. By default a value of zero is used, and provides an even light value from beginning to edge.

Parameters:

exp - The value of the exponent

Throws:

java.lang.IllegalArgumentException - The exponent was less than zero

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getDropOffRateExponent

public float getDropOffRateExponent()

Get the current drop off exponent rate.

Returns:

A value greater than or equal to zero.

setDirection

public void setDirection(float[] dir)
                  throws InvalidWriteTimingException

Set the direction to the new value. Direction is a vector that the light is shining.

Parameters:

dir - The new direction value to use

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

setDirection

public void setDirection(float x,
                         float y,
                         float z)
                  throws InvalidWriteTimingException

Set the direction to the new value. Direction is a vector that the light is shining.

Parameters:

x - The x component of the direction value to use

y - The y component of the direction value to use

z - The z component of the direction value to use

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getDirection

public void getDirection(float[] dir)

Retrieve the current direction vector from the light.

Parameters:

dir - An array to copy the direction into

setPosition

public void setPosition(float[] pos)
                 throws InvalidWriteTimingException

Set the position to the new value. Position is a vector that the light is shining.

Parameters:

pos - The new position value to use

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

setPosition

public void setPosition(float x,
                        float y,
                        float z)
                 throws InvalidWriteTimingException

Set the position to the new value. Position is a vector that the light is shining.

Parameters:

x - The x component of the position value to use

y - The y component of the position value to use

z - The z component of the position value to use

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getPosition

public void getPosition(float[] pos)

Retrieve the current position vector from the light.

Parameters:

pos - An array to copy the position into

setAttenuation

public void setAttenuation(float constant,
                           float linear,
                           float quad)
                    throws InvalidWriteTimingException

Set the attenuation factors for the light. See class header documentation for more inforamtion on these values.

Parameters:

constant - The constant attenuation factor

linear - The linear attenuation factor

quad - The quadratic attenuation factor

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

setAttenuation

public void setAttenuation(float[] values)
                    throws InvalidWriteTimingException

Set the attenuation factors for the light. See class header documentation for more inforamtion on these values.

Parameters:

values - Each value in the order:
[0] The constant attenuation factor
[1] The linear attenuation factor
[2] The quadratic attenuation factor

Throws:

InvalidWriteTimingException - An attempt was made to write outside of the NodeUpdateListener data changed callback method

getAttenuation

public void getAttenuation(float[] values)

Set the attenuation factors for the light. See class header documentation for more inforamtion on these values.

Parameters:

values - Array to copy the values into, in the order:
[0] The constant attenuation factor
[1] The linear attenuation factor
[2] The quadratic attenuation factor

compareTo

public int compareTo(Light l)

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Overrides:

compareTo in class Light

Parameters:

l - The light instance to be compared

Returns:

-1, 0 or 1 depending on order