NAME

DoLightSpreadExp − Create a light attribute object defining light intensity falloff with angle

SYNOPSIS

C:

DtObject DoLightSpreadExp(exponent)
DtReal exponent;

FORTRAN:

INTEGER∗4 DOLTSE(EXPN)
REAL∗8 EXPN

DESCRIPTION

DoLightSpreadExp creates a light studio attribute object that defines a multiplicative factor modifying the light intensity of spot lights as a function of the angle from the light direction.  For any point p, a line can be drawn from p to the light position.  The cosine of the angle between this line and the light direction vector raised to the power exponent is used as a multiplicative factor modifying the light intensity at the point p. 

ERRORS

DoLightSpreadExp will fail if exponent is less than zero. 

[WARNING - value out of range]

DEFAULTS

The default value for DoLightSpreadExp is 0. 

SEE ALSO

DoLightSpreadAngles(3D), DoLightAttenuation(3D), DoLightType(3D)

September 02, 1992