• derived nodes inherit all messages from their base classes
  
• see reset method for default settings
  
• lighting in a scene is based on the number of lights, lighting-model modes, and the material properties of the illuminated objects where the contribution of each light source is the sum of:
  
  1. light source ambient color, scaled by the material ambient reflectance
     
  2. light source diffuse color, scaled by the material diffuse reflectance and the dot product of the vertex normal and the vertex-to-light source vector
     
  3. light source specular color, scaled by the material specular reflectance and a function of the angle between the vertex-to-viewpoint vector and the vertex-to-light source vector
     
• the ambient component is nondirectional and distributed uniformly throughout the environment
  
• the ambient component is reflected from the object independent of surface location and orientation with equal intensity in all directions
  
• the diffuse component takes into account the direction of a light source. The intensity of light striking a surface varies with the angle between the orientation of the object and the direction of the light source -- the diffuse parameter of a material determines how much light is scattered evenly in all directions
  
• the specular component represents reflection off shiny surfaces. Specular lighting operates based on the viewer's position. Maximum specular reflectance occurs when the angle between the viewer and the direction of the reflected light is zero -- the brightness of a specular reflection decays based upon the exponential value shininess
  
• the default direction of the spotlight is down (0,0,-1)
  
• the divergence adjusts the distance from which light comes from infinity, 0.0, to the actual position, 1.0
  
• the falloff reduces the inensity as the angle from the lighting direction increases
  
• the spread sets the cuttoff angle of the intensity from the lighting direction
  
• the attenuation values determine the intensity of light on a surface as:
  1.0 / (constant + linear * distance + quadratic * distance^2)
  where distance is the distance from the light source to the surface
  

constructor spotLight

1 create pfLightSource

destructor ~spotLight

method reset

1 if net master

1.1 set to on
1.2 set attenuation to 1,0,0
1.3 set divergence to 1.0, falloff to 0.0, and spread to 180.0
1.4 set ambient to 0,0,0
1.5 set diffuse to 1,1,1
1.6 set specular to 1,1,1

method message

1 set the light to on
2 set the light to off
3 toggle the light state
4 set the light attenuation (constant,linear,quadratic)
5 set the spotlight divergence [0:1]
6 set the spotlight intensity falloff [0:128]
7 set the spotlight spread angle [0:90|180]
8 set the ambient color of the light
9 set the diffuse color of the light
10 set the specular color of the light

method isOn

method on

method off

method toggle

method setAttenuation

method setCone

method setAmbient

method setDiffuse

method setSpecular