light Last edited 2 months ago2024-09-15 09:16:18 UTC

light - Point Entity

Point-based light that emits light in all directions. It can also be toggled on/off and pulse in a variety of pre-defined styles (as well as custom ones) in a limited fashion.

Attributes

• Name (targetname) - Property used to identify entities.
• Target (target) - No effect.
• Brightness (_light) - First three 3-digit numbers are the color (RGB). The fourth number is the brightness, and can go above 255. e.g. 255 0 0 300 will produce a red light with a brightness of 300 units.
• Appearance (style) - Light appearance. Values:
  • 0 = Normal
  • 1 = Flicker A
  • 2 = Slow strong pulse
  • 3 = Candle A
  • 4 = Fast strobe
  • 5 = Gentle pulse
  • 6 = Flicker B
  • 7 = Candle B
  • 8 = Candle C
  • 9 = Slow strobe
  • 10 = Fluorescent flicker
  • 11 = Slow pulse, no black
  • 12 = Underwater mutation (i.e. constant light source, but placed underwater)
• Custom Appearance (pattern) - Use a string of letters to provide a custom light style (see note).
• ZHLT Fade (_fade) - Divisor for the overall strength of the light without affecting distance (which is controlled by Brightness (_light)). Higher values = weaker light strength. Defaults to 1.0.
• ZHLT Falloff (_falloff) - Light calculation falloff. [🚫Feature removed in default VHLT builds] Values:
  • 0 = Default (Defer to global falloff, which defaults to 2 i.e. Inverse Square)
  • 1 = Inverse Linear
  • 2 = Inverse Square (Default; more akin to real-world light calculation)

Flags

• Initially dark (1) - If this is enabled, the entity will need to be triggered to work.

Notes

• Naming the light will make it ignore its Appearance (style). To get around this, use Custom Appearance (pattern) instead (in particular, the linked page has pattern strings used by the preset appearance values).
• The Custom Appearance (pattern) property allows you to enter a string of up to 63 letters from a to z, representing brightness. If you entered 'abcdefghihgfedcba' then the light would go from bright to dim and back again and then repeat. To use this feature, you must name the light.
• There's a limit of 4 light styles for any given face in the BSP format. Each different light Appearance (style), and each unique name on light* entities, is a different light style, so you want to be careful not to place a lot of lights with differing styles/names in the same area.
• There's a limit of 31 uniquely named lights per map. This includes all light* entities.
• Light from a light_environment entity overrides lighting on entity models if the entities have line of sight to the sky (i.e. sky faces) from the reverse direction of the PYR (angles) values of that light_environment entity. Click this link for more information.
  • Note that the game code uses only the PYR (angles) value for this, unlike the RAD compiler which also uses pitch. As a result, there could be a mismatch in sun lighting on the world vs on models. e.g. PYR of (0 0 0) can override model lighting with sunlight when the sky is visible on the Eastern horizon from its location even if pitch is set to, say, -45. The fix is to only use PYR (angles) to set both Pitch and Yaw, and never use pitch.
  • To block line of sight and have entities take lighting from the ground as normal, use brushes textured with black_HIDDEN on the bottom face, and SKIP on the other faces.
  • To bypass this effect altogether, use light_spot (this entity) with "Is Sky" set to Yes instead of light_environment.
• Tip: Pair light entities with light fixtures so that the light appear more lifelike instead of emanating out of thin air.
• Alternatives to point light:
  • light_spot - directed light
  • light_environment - directed light emanating from the sky
  • Texture lighting using RAD files, info_texlights, or light_surface

Related pages

• In the Beginning Part 4: Basic Lighting
• Tutorial: Light (older)
• Tutorial: The Complete Guide to Lighting (newer, most exhaustive)