Class PointLight

Direct Known Subclasses:
SpotLight

public class PointLight extends Light
The PointLight object specifies an attenuated light source at a fixed point in space that radiates light equally in all directions away from the light source. PointLight has the same attributes as a Light node, with the addition of location and attenuation parameters.

A point light contributes to diffuse and specular reflections, which in turn depend on the orientation and position of a surface. A point light does not contribute to ambient reflections.

A PointLight is attenuated by multiplying the contribution of the light by an attenuation factor. The attenuation factor causes the the PointLight's brightness to decrease as distance from the light source increases. A PointLight's attenuation factor contains three values:

  • Constant attenuation
  • Linear attenuation
  • Quadratic attenuation

A PointLight is attenuated by the reciprocal of the sum of:

    The constant attenuation factor
    The Linear attenuation factor times the distance between the light and the vertex being illuminated
    The quadratic attenuation factor times the square of the distance between the light and the vertex

By default, the constant attenuation value is 1 and the other two values are 0, resulting in no attenuation.

  • Field Details

    • ALLOW_POSITION_READ

      public static final int ALLOW_POSITION_READ
      Specifies that this PointLight node allows reading its position information.
      See Also:
    • ALLOW_POSITION_WRITE

      public static final int ALLOW_POSITION_WRITE
      Specifies that this PointLight node allows writing its position information.
      See Also:
    • ALLOW_ATTENUATION_READ

      public static final int ALLOW_ATTENUATION_READ
      Specifies that this PointLight node allows reading its attenuation information.
      See Also:
    • ALLOW_ATTENUATION_WRITE

      public static final int ALLOW_ATTENUATION_WRITE
      Specifies that this PointLight node allows writing its attenuation information.
      See Also:
  • Constructor Details

    • PointLight

      public PointLight()
      Constructs a PointLight node with default parameters. The default values are as follows:
        position : (0,0,0)
        attenuation : (1,0,0)
    • PointLight

      public PointLight(javax.vecmath.Color3f color, javax.vecmath.Point3f position, javax.vecmath.Point3f attenuation)
      Constructs and initializes a point light.
      Parameters:
      color - the color of the light source
      position - the position of the light in three-space
      attenuation - the attenutation (constant, linear, quadratic) of the light
    • PointLight

      public PointLight(boolean lightOn, javax.vecmath.Color3f color, javax.vecmath.Point3f position, javax.vecmath.Point3f attenuation)
      Constructs and initializes a point light.
      Parameters:
      lightOn - flag indicating whether this light is on or off
      color - the color of the light source
      position - the position of the light in three-space
      attenuation - the attenuation (constant, linear, quadratic) of the light
  • Method Details

    • setPosition

      public void setPosition(javax.vecmath.Point3f position)
      Set light position.
      Parameters:
      position - the new position
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • setPosition

      public void setPosition(float x, float y, float z)
      Set light position.
      Parameters:
      x - the new X position
      y - the new Y position
      z - the new Z position
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • getPosition

      public void getPosition(javax.vecmath.Point3f position)
      Gets this Light's current position and places it in the parameter specified.
      Parameters:
      position - the vector that will receive this node's position
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • setAttenuation

      public void setAttenuation(javax.vecmath.Point3f attenuation)
      Sets this Light's current attenuation values and places it in the parameter specified.
      Parameters:
      attenuation - the vector that will receive the attenuation values
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • setAttenuation

      public void setAttenuation(float constant, float linear, float quadratic)
      Sets this Light's current attenuation values and places it in the parameter specified.
      Parameters:
      constant - the light's constant attenuation
      linear - the light's linear attenuation
      quadratic - the light's quadratic attenuation
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • getAttenuation

      public void getAttenuation(javax.vecmath.Point3f attenuation)
      Gets this Light's current attenuation values and places it in the parameter specified.
      Parameters:
      attenuation - the vector that will receive the attenuation values
      Throws:
      CapabilityNotSetException - if appropriate capability is not set and this object is part of live or compiled scene graph
    • cloneNode

      public Node cloneNode(boolean forceDuplicate)
      Used to create a new instance of the node. This routine is called by cloneTree to duplicate the current node.
      Overrides:
      cloneNode in class Node
      Parameters:
      forceDuplicate - when set to true, causes the duplicateOnCloneTree flag to be ignored. When false, the value of each node's duplicateOnCloneTree variable determines whether NodeComponent data is duplicated or copied.
      See Also: