NAME

DoLightType − Create a light type studio attribute object

SYNOPSIS

C:

DtObject DoLightType(type)
DtObject type;

FORTRAN:

INTEGER∗4 DOLTT(TYPE)
INTEGER∗4 TYPE

DESCRIPTION

DoLightType creates a light type studio attribute object.  The parameter type specifies the lighting model for subsequent lights.  Six light models are currently provided:

DcLightAmbient <DCLTAM>
Light from the light source is equally distributed throughout the scene. The total ambient light in the scene is the combination of all ambient lights in the scene.

DcLightInfinite <DCLTIN>
The light source is at infinity.  All rays of light entering the scene will appear to be parallel. The vector (0.,0.,-1.) is transformed by the current transformation matrix to determine the light direction.

DcLightPoint <DCLTPT>
The light source is a point source that radiates light outward uniformly in all directions from the light position. The point (0.,0.,0.) is transformed by the current transformation matrix to determine the light position.

DcLightPointAttn <DCLTPA>
The light source is just like DcLightPoint <DCLTPT> but with the additional attribute DoLightAttenuation controlling the falloff of the light intensity as a function of the distance from the light source. 

DcLightSpot <DCLTSP>
The light source is a directed point source that radiates light outward from the light position and whose light intensity decreases as a function of the angle from the light direction. The point (0.,0.,0.) is transformed by the current transformation matrix to determine the light position. The vector (0.,0.,-1.) is transformed by the current transformation matrix to determine the light direction. The light attributes DoLightSpreadAngles and DoLightSpreadExp control the width and falloff of the light intensity as a function of the angle from the light direction. 

DcLightSpotAttn <DCLTSA>
The light source is just like DcLightSpot <DCLTSP> but with the additional attribute DoLightAttenuation controlling the falloff of the light intensity as a function of the distance from the light source. 

DEFAULTS

The default DoLightType is DcLightInfinite <DCLTIN>. 

SEE ALSO

DoLight(3D), DoLightSpreadAngles(3D), DoLightSpreadExp(3D), DoLightAttenuation(3D)

September 02, 1992