[HL] Implement env_fog for map-makers

[rtxa]

Considering you are adding new features to the engine/client with the 25th anniversary update like the func_vehicle entity I wonder if you can add support for the entity env_fog in Half-Life 1. This is an entity which allows to add fog to the map and is already implemented in CS 1.6/CZ. You are allowed to change its color, density, start and end distance.

I think is a cool feature for modders and level designers which adds a lot of personality and ambience to maps. SoloKiller has already an implementation of this feature which could be useful. https://github.com/SamVanheer/halflife-fog/commit/1c45a30f15c076a9e02fd6597a8451b3b9fdb474

Example from CS 1.6:

[andreiseverin]

• env_snow and env_rain too

[DeafMan1983]

And advanced fog effects like you walk near to house and you see like inside window of house and this house should block against fog func_fog_blockeras solid entity inside room of house or factory.

// EDIT: I think func_fog_blocker is better than info_fog_blocker is as solid brush when you're player and you move to tunnel or cave than fog shouldn't put in tunnel or cave ( example in Xen or desert )

You go away and it looks like env_fog_aligned but fog should to move only ( not rotating )

// EDIT env_fog_stayed is just dead fog ( it won't move like example player goes in high building like Dubai hotel and you see in top like fog or cloud effect you see and you are behind bottom and you will see fog is in top of sky. ) I will show you an example:

Or falling bottom area or bridge over realistic fog like other mod but I wish we have real env_fog_stayed then stayed fog should stay and doesn't move. Example you fall from subway system like start of Half-life. Without replaced texture with gradiant effect with black color. You just save textures for small wads... It is very better than old Half-Life textures. I will show an example falling black hole like this:

Or why not we need to put env_sky like Half-Life 2's sky_camera

[Hedgefog]

Would be awesome!

[SamVanheer]

If this is to be considered then all of the weather effects and related effects should be made available as well. Fog, rain, snow, grass sprites on textures, etc. Condition Zero has its own material system to make this work so that might also be needed.

The original material system would also need the snow material type added along with footsteps and impact sounds for completeness sake.

[DeafMan1983]

Great idea @SamVanheer, I hope Valve Software Team works very hard-coded. // Check out my improved comment!