3D Graphics Programming with QuickDraw 3D 1.5.4

Light Attenuation Values

Most types of lights have an attenuation value that determines how quickly, if at all, the intensity of a light changes as a function of the distance of the illuminated object from the light source. You can use these constants to specify an attenuation value:



 
typedef enum TQ3AttenuationType {

    kQ3AttenuationTypeNone,

    kQ3AttenuationTypeInverseDistance,

    kQ3AttenuationTypeInverseDistanceSquared

} TQ3AttenuationType;

Constant descriptions

kQ3AttenuationTypeNone: The intensity of the light is not affected by the distance from the illuminated object.
kQ3AttenuationTypeInverseDistance: The intensity of the light is inversely proportional to the distance from the illuminated object.
kQ3AttenuationTypeInverseDistanceSquared: The intensity of the light is inversely proportional to the square of the distance from the illuminated object.