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Change health and stamina, or add a new vital

A vital is a number that goes down and comes back up. Health and stamina ship with the template, and the system is written so a third one, hunger or thirst or radiation, is a Data Asset and a row in an array.

Every vital is described by one Data Asset. Every character that can be hurt carries one BP_VitalsSystem component holding the list of vitals it owns.

  • The component: Content/TheLastTemplate/Blueprints/ActorComponents/BP_VitalsSystem
  • The Data Asset class: Content/TheLastTemplate/Blueprints/DataAssets/Vitals/BP_VitalData
  • The two that ship: Content/TheLastTemplate/Blueprints/DataAssets/Vitals/Childs/
  • The list of types: Content/TheLastTemplate/Blueprints/Enumerations/Vitals/E_VitalsType

What ships

Two Data Assets, one of type Health and one of type Stamina.

Data Asset Vital Max Amount Vital Tick Decrementation
DA_Vital_Health 100 0
DA_Vital_Stamina 200 2

Four Blueprints carry the component:

Blueprint Starts with
BP_PlayerCharacter health and stamina
BP_NPCCharacter health
BP_ZombieCharacter health
BP_Dummy health

Only the player has stamina. Nothing stops you from giving an NPC one, but nothing spends it either.

The six fields of a vital

Open DA_Vital_Health and you see the whole of BP_VitalData.

Field What it does
Vital Name A label. Free text.
Vital Icon A texture for your own UI.
Vital Type Which vital this is, picked from E_VitalsType. This is how the rest of the game finds it.
Vital Color A colour for your own UI.
Vital Max Amount The ceiling. Add vital amount never goes past it.
Vital Tick Decrementation How much is taken every tenth of a second while the vital is ticking.

Vital Name, Vital Icon and Vital Color are there for you. Nothing in the shipped HUD reads them, so leave them empty or fill them in, either is fine.

Vital Type is the important one. Health, damage, healing items, the death check and the HUD all look a vital up by type, and they take the first match in the list. Two vitals of the same type means the second one can never be reached.

Change max health or max stamina

  1. Open Content/TheLastTemplate/Blueprints/DataAssets/Vitals/Childs/DA_Vital_Health.
  2. Set Vital Max Amount to the value you want.
  3. Save.
  4. Open BP_PlayerCharacter, select the BP_VitalsSystem component, and in Vitals set Current Amount on the health row to the same value.
  5. Repeat step 4 on BP_NPCCharacter, BP_ZombieCharacter and BP_Dummy if you want them to follow.

Current Amount is not filled in from Vital Max Amount

The starting value of each vital is authored per actor, in the Vitals array on the component. Nothing copies Vital Max Amount into it at Begin Play. Raise health to 200 and forget step 4 and the character still spawns at 100, with a health bar sitting at half.

The drain tick, and how to stop it

The component starts a repeating timer at Begin Play. Every tenth of a second it walks the Vitals array and, for each row whose Is Paused Tick is unchecked, removes Vital Tick Decrementation from it.

Health ships at 0, so health never drains on its own. Stamina ships at 2, which is 20 a second, so a full 200 empties in ten seconds of draining.

Each row of Vitals has three fields:

Field What it does
Vital Asset The BP_VitalData this row uses.
Current Amount What the character starts with.
Is Paused Tick Checked means this vital is not draining right now.

There are three ways to stop a drain:

  • Set vital pause tick, with a Type and a Pause boolean, freezes one vital and leaves the others running. This is what the player character uses to hold stamina still when you are not sprinting.
  • Pause tick decrementation and Start tick decrementation stop and restart the whole timer, every vital at once.
  • Setting Vital Tick Decrementation to 0 on the Data Asset means the tick still runs but takes nothing.

Give one character its own values

Two ways, and they are not the same.

Different starting amount, same ceiling. Select the actor, select its BP_VitalsSystem component, and change Current Amount on the row. A weakened NPC that starts at 40 of 100 needs nothing else.

Different ceiling. Duplicate DA_Vital_Health, name it for what it is, set its Vital Max Amount, then point that actor's Vital Asset at the new Data Asset. Keep Vital Type on Health so damage, death and healing still find it.

A placed actor works too. Select the instance in the level and edit Vitals on it, and only that one is affected.

Add a third vital

Say you want hunger.

  1. Open Content/TheLastTemplate/Blueprints/Enumerations/Vitals/E_VitalsType and add an enumerator. Set its display name to Hunger. Save.
  2. Duplicate DA_Vital_Stamina, name it DA_Vital_Hunger. Set Vital Type to Hunger, Vital Max Amount to what you want, and Vital Tick Decrementation to how fast hunger should fall every tenth of a second.
  3. Open BP_PlayerCharacter, select the BP_VitalsSystem component, add a row to Vitals. Set Vital Asset to DA_Vital_Hunger, Current Amount to the starting value, and leave Is Paused Tick unchecked so it drains.
  4. Feed it. An item that restores hunger is a BP_ItemDataAsset whose effect calls Add vital amount with type Hunger, the way BP_ItemEffect_Heal does for health. See Add a new item.

That is a working vital. Be honest with yourself about what it does not do yet:

  • it drains and refills, and it clamps at 0 and at Vital Max Amount, but reaching 0 does nothing. Only the Health type kills.
  • none of the four multipliers apply to it. Health gets Healing Multiplier and Damage Taken Multiplier, stamina gets Stamina Recovery Multiplier and Stamina Drain Multiplier, a third vital gets neither.
  • nothing draws it. The HUD is built for the two that ship, so you add the bar yourself.

If you want hunger to hurt you when it empties, remove health from your own logic when it hits 0. There is no built in link between vitals.

The four multipliers

They live on the component itself, all shipped at 1, all category Skills.

Field What it scales Skill that drives it
Damage Taken Multiplier Every point of health removed. DA_Skill_DamageResistance
Healing Multiplier Every point of health added. DA_Skill_HealingPower
Stamina Recovery Multiplier Every point of stamina added. DA_Skill_StaminaRecovery
Stamina Drain Multiplier The stamina drain tick only. DA_Skill_SprintEndurance

Set them by hand for a difficulty setting, or leave them to the skill effects. Each skill in Content/TheLastTemplate/Blueprints/DataAssets/Skills/Childs/ has a matching effect Blueprint that writes one of these when the player buys a level. See Add or change a skill.

Invulnerable, also on the component, blocks the death step. It does not block damage.

Read a vital from your own widget

Get vital takes a Type and gives you back the row, which you break into Vital Asset, Current Amount and Is Paused Tick. Divide Current Amount by the Vital Max Amount of the Vital Asset and you have a percent for a progress bar. That is what BP_LifeCharacterWidget does for the health ring and the stamina bar. See The HUD widgets.

The functions you will use from outside:

Function What it does
Get vital The row for a type. Read only.
Add vital amount Adds, applies the healing or recovery multiplier, clamps at Vital Max Amount.
Remove vital amount Removes, applies Damage Taken Multiplier on health, clamps at 0, and runs the death check.
Change vital amount Writes a value straight in. No multiplier, no clamp, no death check.
Set vital pause tick Freezes or unfreezes one vital's drain.
Get is dead Whether this character has already died.
Set invulnerable state Turns the death check off and on.

Two event dispatchers fire on the component: On Health Damage every time health drops, and On Death the moment it reaches 0 on a vulnerable character. Bind to them instead of polling.

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