env_bubbles
env_bubbles is a point entity available in all 
GoldSrc games. It creates an area of rising bubbles.
Key Values
Targetname:
- Name
(targetname)<targetname> - The targetname that other entities refer to this entity by.
ZHLT:
- ZHLT Lightflags
(???)<choices> - Special lighting behavior. Only available if using Zoner's Half-Life Compile Tools.
- 0 : "Default"
- 1 : "Embedded Fix"
- 2 : "Opaque (blocks light)"
- 3 : "Opaque + Embedded fix"
- 6 : "Opaque + Concave Fix"
- Light Origin Target
(???)<string> - Used to define a target to sample lighting from.
- Bubble density
(density)<integer> - This is the density of bubbles spawned.
- Bubble frequency
(frequency)<integer> - The higher the value here, the greater the frequency bubbles will appear at.
- Speed of current
(current)<integer> - The higher this value, the more bubbles drift in the direction specified by the entity angle.
Flags
- [
1] : Start off
