Detailed Description

struct A3DGraphDirectionalLightData

Data for a directional light source entity (A3DGraphDirectionalLight)

A directional light simulates a source which is far away from the scene. In that situation, all light rays are coming from the same direction, regardless of the position of the illuminated object or the viewer. The illumination only depends on the light orientation, and not its position.



All colors within this structure are global indexes to RGB color codes. The actual values can be queried using A3DGlobalGetGraphRgbColorData.

A3DGraphDirectionalLightData is one of the four light source types provided by HOOPS. It is associated to the kA3DTypeGraphDirectionalLight entity type. The other available light sources are A3DGraphAmbientLightData, A3DGraphPointLightData and A3DGraphSpotLightData.


The direction of the light source is expressed with m_sDirection in world space coordinates.

Ligthing color

The color of a lighting source is usually described with a single color, referenced to by m_uiAmbientColorIndex which is applied to the receiving material. Different implementations can take benefit from making the distinction between ambient, diffuse and specular colors upon computing light. These additional information can be written into m_uiDiffuseColorIndex and m_uiSpecularColorIndex. When ununsed, these values are either set to the same value as m_uiAmbientColorIndex or A3D_DEFAULT_COLOR_INDEX.

Public Members

A3DUns32 m_uiAmbientColorIndex

The main or ambient color of the light source.

A3DUns32 m_uiDiffuseColorIndex

The diffuse color of the light source.

A3DUns32 m_uiSpecularColorIndex

The specular color of the light source.

A3DDouble m_dIntensity


A3DVector3dData m_sDirection