Sim/graphics/animation/lights/airplane generic light
RGB form a 3-part normalized direction vector - see PluginsAndObjects.
A is the index of the generic light number.
Alpha is modulated by the brightness of the light and view angle; RGB is set to 1.0.
This light will turn off if the generic light is off.
This provides a generic light. It has directional properties and follows the brightness of the generic lights.