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Health, damage and new vitals

Health and stamina are two rows of one array on BP_VitalsSystem. This page shows how to hurt a player, heal one, read the values, and add a third vital of your own.

  • The component: Content/MPFriendslop/Blueprints/ActorComponents/BP_VitalsSystem
  • The vital Data Asset class: Blueprints/DataAssets/Vitals/BP_VitalData
  • The vital Data Assets: Blueprints/DataAssets/Vitals/Childs/
  • The list of vital types: Blueprints/Enumerations/Vitals/E_VitalsType

Other systems never cast to the character to find the vitals. They call GetVitalComponent from BPI_VitalManagerInterface on the pawn, and the pawn returns its BP_VitalsSystem. Do the same in your own Blueprints.

The component

The fields are on BP_VitalsSystem, in Settings|Vitals.

Field What it does Shipped on the player
Vitals One row per vital: its Data Asset, its Current Amount, and Pause Decrementation to stop it draining DA_Health_Vital at 100, DA_Stamina_Vital at 100
Invulnerable When on, health does not go down: damage and RemoveVitalAmount on health do nothing. Healing still works. The component also turns it on at death, so a dead player cannot die twice off
Damage Vital Type The vital that engine damage takes from Health
Impact Flash Material The overlay put on every mesh of the owner when it takes damage, seen by every player M_ImpactFlash
Impact Flash Duration How long that flash lasts, in seconds 0.5
Kill Credit Seconds A death counts as a kill for the last player who damaged the owner within this many seconds. OnKilled gives that player 5

Only Health kills. Any other vital can reach 0 without killing anyone.

The same component makes an enemy damageable: BP_EnemyBase, the parent of the Warden, carries one too. For damage on actors that are not the player, see How weapons work.

Hurt a player

Call Unreal's own Apply Damage on the player pawn, on the server. That is all. The component listens to the owner's On Take Any Damage, removes the damage from Damage Vital Type, and plays the impact flash.

Anything that already deals engine damage (a gun, a melee swing, your own trap) hurts players with no extra work.

To kill outright instead, skip the vitals: call Kill on the pawn's BP_DeathComponent, on the server. BP_DebugKillVolume in Blueprints/Environments/ does exactly that when a pawn walks in. See Death, revive and the spectator.

If you need to take from a vital other than health, call RemoveVitalAmount with the vital type and the amount, on the server. The value stops at 0.

Heal a player

Call AddVitalAmount with the vital type and the amount, on the server. The value stops at the Vital Max Amount of that vital's Data Asset.

To heal from an item, there is nothing to call: an item with Restored Vital and Restore Amount does it through BP_ConsumableComponent. DA_Item_Medkit restores 50 health. See Add an inventory item.

Read a value

  1. Call GetVitalComponent on the pawn (the BPI_VitalManagerInterface message).
  2. Call GetVital on the result with the vital type.
  3. Break the returned S_Vitals and read Current Amount.

For the maximum, read Vital Max Amount on the row's Vital Asset. GetIsDead tells you if the player is dead.

To react to a change instead of polling, bind a dispatcher.

Dispatcher When it fires Fires on
OnVitalsChanged Any vital changed. Bind this one for a HUD every player
OnVitalDepleted A vital just reached 0, with its type server
OnDied Health reached 0 server
OnKilled Health reached 0. Gives Victim and Killer, the controller of the last player who damaged it within Kill Credit Seconds, or none. The arena counts its kills with it server
OnDamageTaken On BP_DamageFeedbackComponent: the watched vital went down, with the amount owning player

The damage feedback

BP_DamageFeedbackComponent on the pawn gives the hurt player a sound, a camera shake and a red screen edge. It only runs on the hurt player's own machine and sends nothing over the network.

Field What it does Shipped value
Watched Vital The vital whose drop counts as a hit. Empty turns the component off DA_Health_Vital
Damage Sound Played in 2D on a hit CUE_Damage_Hurt
Damage Shake Camera shake played on a hit CS_DamageHit

The fields are in Settings|Damage. The red edge is WBP_DamageVignette, inside WBP_Gameplay, and it listens to OnDamageTaken. Bind the same dispatcher for your own hit effect or rumble.

Sprinting drains stamina, not health, so it does not flash the screen.

Add a vital

A hunger, oxygen or sanity bar, for example.

  1. Open E_VitalsType and add an entry, for example Hunger.
  2. In Blueprints/DataAssets/Vitals/Childs/, duplicate DA_Stamina_Vital and name it DA_Hunger_Vital.
  3. Open it and set the fields below. They come from BP_VitalData, the class of every vital Data Asset.
  4. Open BP_FriendslopCharacter, select BP_VitalsSystem, and add a row to Vitals with your Data Asset and a starting Current Amount.
Field What it does DA_Health_Vital
Vital Type Which E_VitalsType entry this asset is Health
Vital Color The colour of this vital's glyph and number on the HUD green
Vital Max Amount The ceiling for healing 100
Vital Tick Decrementation Removed every 0.1 seconds on the server. 1 means 10 per second. 0 means it never drains 0

Your vital now drains, heals, fires the dispatchers and reaches every player. It does not show on the HUD yet: WBP_Vitals draws two fixed rows, HealthRow and StaminaRow, not one row per entry of Vitals. Showing a third one is an edit of WBP_Vitals: a copy of StaminaRow with your own icon, styled in AttachToPawn and refreshed in RefreshValues like the other two. The steps are on The HUD, and adding to it.

Warning

A pawn that has BP_VitalsSystem but does not implement BPI_VitalManagerInterface is invisible to the rest of the template: no HUD values, no stamina, no damage feedback, and the Warden will not target it. There is no error. See How the player character works.

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