• derived nodes inherit all messages from their base classes
  
• see reset method for default settings
  
• this node can also be created with the alias: environment
  
• volumes are defined by a box, cylinder, sphere, point or infinite volume
  
• for volume messages refer to the ygSpace node
  
• environment settings are applied when the user enters the space
  
• the last environment defined will be applied when environments overlap
  
• objects located outside of the field defined by the clipping planes will not be drawn
  
• fog is the atmospheric effect of aerosol water particles that occludes vision over a distance
  
• fog color is blended with the pixel color based on the range from the viewport and the fog function
  
• the fog function is specified by the following "type" options:
  
  • linear (computes fog linearly at pixels),
    
  • exp (computes fog exponentially at pixels (ex)),
    
  • exp2 (computes fog exponentially at pixels (ex squared))
    
• "onset" is the distance from the viewport at which the fog begins to take effect.
  
• "opaque" is the distance at which the fog is 100% opaque, objects beyond this distance will not be visible
  

method activeEnvironment_

constructor ygEnvironment

destructor ~ygEnvironment

method reset

1 set near and far planes to 0.1 and 1000
2 set sky color to black (0,0,0)
3 set fog to off

method message

1 set the near and far clipping planes
2 set the sky color
3 set the fog properties (type, color, onset, opaque)

method setClip

method nearClip

method farClip

method setSkyColor

method skyColor

method fogOff

method setFog

method app

1 if space contains user then apply settings

method apply

1 if properties have changed

1.1 set world clipping planes
1.2 set world sky color
1.3 if fog then set world fog properties

2

 The activeEnvironment_ class variable is intended to take care
      of cases where environment nodes overlap.  It keeps track of which
      node is 'active', i.e. the last one to apply itself.  Effectively,
      when there is an overlap, the winning node changes the other node's
      lastApply value to let the other node know that it has been un-applied,
      allowing it to re-apply itself when the user gets out of the overlap
      region.