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The SEDRIS Data Representation Model
APPENDIX A - Classes Directional Light Behaviour |
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An instance of a concrete class derived from this DRM class specifies a directional light having a direction and lobe shape defined by a component <Lobe Data> instance. The lobe shape parameters are used by sub-classes to specify cones, pyramids, blend geometry, and so on.
Directional lights can have both a primary and a secondary colour. These are specified by the <Colour> components of the parent <Geometry Representation> that have colour_mapping values of Lgt_Render_Bhvr_Primary and Lgt_Render_Bhvr_Secondary, respectively.
See concrete subclasses for examples.
This can be done using either a <Cone Directional Light> or a <Pyramid Directional Light> with primary and secondary colours. Set the horizontal and vertical widths of the lobe to 180 degrees and invisible_behind to SE_TRUE.
No; it does not represent the location of any light(s) that use this behaviour. It is the reference location for the direction of the light (as expressed the <Reference Vector> components of the <Lobe Data>).
In most SRFs, directions shall refer to a location to account for the curvature of the earth. Even in linear space SRFs, localized directions may be important (See Example 1).
This specifies the lobe shape.
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