2.4.7 Light Sources

The light_source is not really an object. Light sources have no visible shape of their own. They are just points or areas which emit light. They are categorized as objects so that they can be combined with regular objects using union. Their full syntax is:

LIGHT_SOURCE:
    light_source
    {
        <Location>, COLOR
        [LIGHT_MODIFIERS...]
    }
LIGHT_MODIFIER:
    LIGHT_TYPE | SPOTLIGHT_ITEM | AREA_LIGHT_ITEMS |
    GENERAL_LIGHT_MODIFIERS
LIGHT_TYPE:
    spotlight | shadowless | cylinder | parallel
SPOTLIGHT_ITEM:
    radius Radius | falloff Falloff | tightness Tightness |
    point_at <Spot>
PARALLEL_ITEM:
    point_at <Spot>
AREA_LIGHT_ITEM:
    area_light <Axis_1>, <Axis_2>, Size_1, Size_2 |
    adaptive Adaptive | jitter Jitter | circular | orient
GENERAL_LIGHT_MODIFIERS:
    looks_like { OBJECT } |
    TRANSFORMATION fade_distance Fade_Distance |
    fade_power Fade_Power | media_attenuation [Bool] |
    media_interaction [Bool] | projected_through

Light source default values:

LIGHT_TYPE        : pointlight
falloff           : 70
media_interaction : on
media_attenuation : off
point_at          : <0,0,0>
radius            : 70
tightness         : 10

The different types of light sources and the optional modifiers are described in the following sections.

The first two items are common to all light sources. The <Location> vector gives the location of the light. The COLOR gives the color of the light. Only the red, green, and blue components are significant. Any transmit or filter values are ignored.

Note: you vary the intensity of the light as well as the color using this parameter. A color such as rgb <0.5,0.5,0.5> gives a white light that is half the normal intensity.

All of the keywords or items in the syntax specification above may appear in any order. Some keywords only have effect if specified with other keywords. The keywords are grouped into functional categories to make it clear which keywords work together. The GENERAL_LIGHT_MODIFIERS work with all types of lights and all options.

Note: that TRANSFORMATIONS such as translate, rotate etc. may be applied but no other OBJECT_MODIFIERS may be used.

There are three mutually exclusive light types. If no LIGHT_TYPE is specified it is a point light. The other choices are spotlight and cylinder.

More about "translate"

• 1.2.7.1.1 Translate in 1.2.7.1 Transformations
• 2.8.5 Transformations in 2.8 Quick Reference

More about "rotate"

• 2.2.1.4.5 Functions in 2.2.1.4 Vector Expressions
• 1.2.7.1.3 Rotate in 1.2.7.1 Transformations
• 2.8.5 Transformations in 2.8 Quick Reference