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 Detail

      • ALLOW_POSITION_READ

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

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

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

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

      • 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 Detail

      • 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