Ammo Balancing in Half-Life : Alyx

A major part of the core tension of Half-Life: Alyx comes from the player's limited resources. Your ammo is constantly running low, and every missed shot or poorly used weapon, matters. This all comes from spot on ammo balancing. There's no "magic bullet" to achieve this perfectly every time, but Half-Life: Alyx does include several dynamic systems that try to remove any outliers, and keep players in the perfect levels of danger. These two systems are Ammo Removal and Ammo Drain.

Todo: Page under construction

Ammo Removal

Ammo Removal is a system that will remove items from the world if the player has too many of it. It can be enabled with this setting on most items.

Consider this a lot like the "max ammo" in most other games. The systems strives to keep the player's inventory within certain numbers.

These numbers can be found in the Skill.cfg (normal difficulty values below).

hlvr_player_ammobal_removeat_pistol			"60"
...
hlvr_player_ammobal_removeat_shotgun		"12"
...
hlvr_player_ammobal_removeat_rapidfire		"150"

The game checks the player's inventory (including ammo in a weapon) against these values when an item is loaded in.

This can be when the item enters the Potential Visibility Set or is spawned via a Point_template.

If the player has more then these values, the item is removed.

Keep in mind, this includes items such as grenades; if the player has this item in their inventory, a new one will not be spawned.

Note:THIS SYSTEM IS NOT AWARE OF OTHER NEARBY ITEMS! Only what the player currently has.

Due to the "all or nothing" system, supplies are often given one at a time

However, there is more nuances to this system, as never finding an item for long periods of time can be frustrating.

There exists an invisible counter. After seven items have been removed, the eighth one will not be.

After that , the counter starts again.

There is some additional logic when it comes to health syringes:

• If you have full health and no syringe in a pocket, there is a random chance of the item spawning
• If you have less than full health and no syringe in a pocket, the item will always spawn
• If you have a syringe in a pocket, the item will not spawn (respecting the above counter)

Todo: This was tested on normal difficulty, hard difficulty has additional settings that can change this

Ammo Drain

hlvr_player_ammobal_min_pistol				"20"
hlvr_player_ammobal_max_pistol				"60"
...
hlvr_player_ammobal_min_shotgun				"8"
hlvr_player_ammobal_max_shotgun				"12"
...
hlvr_player_ammobal_min_rapidfire			"90"
hlvr_player_ammobal_max_rapidfire			"150"

hlvr_player_ammobal_drain_pistol			"4"
...
hlvr_player_ammobal_drain_shotgun			"6"
...
hlvr_player_ammobal_drain_rapidfire			"4"

sk_zombie_max_additional_ammo_shots			"18"
sk_headcrab_max_additional_ammo_shots		"4"
sk_barnacle_max_additional_ammo_shots		"8"
sk_combine_max_additional_ammo_shots		"16"

Best Practices

The Combine Locker prefab is often used to efficiently spawn ammo

Pacing scavenging can help reduce fatigue

Keeping supplies varied ensures the player always has options

My Output	Target Entity	Target Input	Parameter	Delay
Ouput_OnHackSuccess	[locker_template]	ForceSpawn		0.00

(temporary text) These additional "safety nets" all point to one fact: this system is not meant to prevent the player's inventory from "snowballing" just slow it down.

It encourages the player's inventory to stay in a certain area, but it does not prevent it from exceeding that. Thorough players can still find an advantage.

This won't solve poor designer choices.

See Also

• ai_attached_item_manager
• Prefabs and Instances
• Trigger Player Out Of Ammo