light_environment Last edited 9 months ago2024-01-20 16:03:59 UTC

light_environment - Point Entity

Attributes

• Name (targetname) - Property used to identify entities.
• Pitch, Yaw, Roll (angles) - Sets the pitch (up/down), yaw (left/right) and roll (bank) respectively.
• Pitch (pitch) - A negative number will give downward pitch (which is normally what you want).
• Brightness (_light) - The first three 3-digit numbers are the colour (RGB) and the fourth is brightness/light intensity (e.g. 248 244 237 350).

ZHLT/VHLT-specific keyvalues:

• Ambient Color (_diffuse_light) - Diffused light colour and brightness. This simulates diffuse light usually from blue sky.
• Sun Spread (_spread) - Diffuses the shadow of the sunlight. Values range from 0 to around 10 (0 being sharp shadows).

Positioning logic

Notes

• Sky brushes must have the "SKY" texture on all faces or they won't reliably emit light (depends on version of HLRAD used).
• The key pitch have the same function as the one in angles, although if you add a value (≠0) to pitch it will overwrite the one in angles. Roll has no effect at all.
• For modern compiler, you are not advised to use multiple light_environment in a map. However, you can still use multiple light_environment for multiple colors.
• This entity doesn't spawn a visible source of light in the sky. Therefore, the sun or moon must be part of the skybox as a picture for visual effects.
• The angles/angle+pitch and brightness values of this entity is used to override lighting on models. If the entity has direct line of sight to the sky (i.e. a "SKY" face) in the reverse direction of this light_environment entity's angles/angle+pitch value, its lighting will be overridden with values calculated from the brightness of this light_environment entity.
  • To break line of sight and have entities take lighting from the ground as normal, use a brush textured with black_HIDDEN facing down above the affected area, and SKIP on the other faces.
  • To avoid this effect altogether, use light_spot with "Is Sky" keyvalue set.
• The ZHLT/VHLT keyvalues may be missing in your copy of halflife.fgd. To add them, open the file in Notepad (or other suitable text editor). Find the line that starts with @PointClass and contains the text = light_environment, and between the brackets that follow the above line, add the following lines:

_spread(integer) : "Spread Angle" : 0 : "Spread angle for soft shadows."
_diffuse_light(color255) : "Diffuse Light" : "255 255 128 50" : "Diffuse light color. Delete if diffuse light is normal."

Balancing Brightness, Ambient Color, and Sun Spread

Here's a very rough guide on how to balance the three values:

• On overcast skies, the ambient light should contribute more light than sunlight.
• The sun's shadow gets more diffused the more overcast the sky is

This all depends on the choice of skybox that you use. Most of them are set on a clear sky which rules out any pressing need to set the sun spread value.

Also worth mentioning the lightmap resolution is the hard limit on how sharp shadows can be.

Related pages

• Tutorial: Environment
• Tutorial: Light
• Tutorial: Dark Outdoor Maps
• VERC: Using Skys in Half-Life
• Vlatitude: Advanced Lighting

Example maps

• VERC Archive: lights1.zip