Game Manager

Health System

Give any GameObject a health bar. Wire hazards to TakeDamage(), wire onDeath to a restart or respawn — the manager handles everything in between. Works for players, enemies, and destructible objects.

Damage, healing, and death events

Low health threshold warning

Built-in health bar with gradient

Persists health between scenes

Getting started

Minimal setup

Four steps. The bar and text UI are optional — the events are all you actually need.

1

Add GameHealthManager to a GameObject

Create an empty GameObject named HealthManager and attach GameHealthManager. Set Max Health and Current Health to your starting value (e.g. 100).
2

Wire hazards to TakeDamage()

On your hazard object (spike, enemy, lava zone), add InputTriggerZone with tag Player. Wire On Trigger Enter → GameHealthManager.TakeDamage(10). The int parameter is the damage amount.
3

Wire onDeath to a restart or respawn

Select GameHealthManager and find the onDeath event. Wire it to ActionRestartScene.RestartCurrentScene() or ActionRespawnPlayer.RespawnToCheckpoint().
4

(Optional) Enable Show UI or Show Bar

Check Show UI to get a text display ("HP: 75 / 100") and/or Show Bar for a fill bar. Both create their own Canvas — no extra setup required. Adjust position with the position fields.

⚠️

TakeDamage() ignores calls after death

Once health reaches zero, TakeDamage() does nothing — onDeath fires exactly once. This prevents multiple death triggers stacking up when the player touches several hazards simultaneously. Call FullHeal() or SetHealth() to revive.

Wiring behavior

Events

Wire these to any function. Every gameplay consequence of a health change should live in an event, not in code.

Event	Parameters	When it fires
onHealthChanged	int current, int max	Every time health changes (damage or heal). Wire to a custom GameUIManager display or any value-driven effect.
onDamageReceived	—	Any time damage is taken. Wire to a hurt sound, screen flash, or camera shake.
onHealthGained	—	Any time health is restored. Wire to a heal sound or visual effect.
onLowHealthReached	—	Fires once when health drops to or below the Low Health Threshold. Wire to a warning music sting or red vignette. Default threshold: 25.
onLowHealthRecovered	—	Fires once when health recovers above the threshold. Wire to cancel the warning effect.
onDeath	—	Fires when health reaches zero. Wire to restart, respawn, or game-over screen.
onRevived	—	Fires when health is set above zero after death. Wire to revival effects.

Display options

Built-in UI

Enable Show UI and/or Show Bar to get a self-contained display with no Canvas setup required. Both can be active at the same time.

Show UI

Text display

Shows "HP: 75 / 100" (or just "HP: 75" with Show Max unchecked). Position it anywhere on screen with the Text Position field (top-left origin). Customize label prefix, font size, color, and animation (Punch Scale or Fade Flash on each hit).

Show Bar

Fill bar

A horizontal health bar with a gradient that transitions red → yellow → green by default. Set position and size independently from the text. The bar animates smoothly by default — disable Animate Bar for instant jumps.

💡

Using an external HUD instead?

If you have a Canvas already set up, wire onHealthChanged to GameUIManager's value display instead of using Show UI. Don't use both — they'll stack and create duplicate displays. See the UI Implementation guide for details.

Common patterns

Recipes

Player health with restart

The most common setup

Max Health100

Low Threshold25

Show Bartrue

Hazard → TakeDamage(10)

onDeath → ActionRestartScene.RestartCurrentScene()

Player health with respawn

Use with checkpoints

Persist Across Scenestrue

On RestartReset To Default

onDeath → ActionRespawnPlayer.RespawnToCheckpoint()

onDeath → FullHeal() (after a short delay)

Enemy with death event

Attach to the enemy GameObject

Max Health30

Show Bartrue

Projectile → TakeDamage(10)

onDeath → SetActive(false) or Destroy

onDeath → GameCollectionManager.Increment(1)

Low health warning

Danger zone feedback

Low Threshold25

onLowHealthReached → Play warning music sting

onLowHealthReached → Enable red vignette overlay

onLowHealthRecovered → Disable vignette overlay

Inspector reference

All fields

Field	Default	What it does
Max Health	100	Maximum health value. TakeDamage and Heal are both clamped to this range.
Current Health	100	Starting health. Can be set below Max Health to start damaged.
Low Health Threshold	25	When health drops to this value or below, onLowHealthReached fires.
Persist Across Scenes	false	Saves current health to carry over on scene load. Add the manager to each scene — only the value travels.
On Restart	Reset To Default	When RestartScene() is called: Reset To Default returns to the Inspector starting value; Keep Value preserves current health.
Show UI	false	Creates a text display ("HP: 75 / 100") at runtime. Customizable prefix, position, font size, color.
Show Max In Text	true	Shows "HP: 75 / 100" when on, "HP: 75" when off.
Value Animation	Punch Scale	Animation on the text each time health changes: None, Punch Scale, or Fade Flash.
Show Bar	false	Creates a fill bar at runtime. Bar color tracks the gradient (red → yellow → green by default).
Bar Gradient	red→yellow→green	Color at each health percentage. Edit in the Inspector gradient editor to match your art style.
Animate Bar	true	Smoothly animates bar fill changes. Disable for instant updates.

Public Method	Parameter	What it does
TakeDamage()	int amount	Reduces health by amount. Ignored if already dead.
Heal()	int amount	Restores health by amount, capped at Max Health. Ignored if dead.
FullHeal()	—	Restores health to Max Health. Does not revive from death — use SetHealth(max) for that.
SetHealth()	int value	Sets health to an exact value. Can revive (if above 0) or kill (if 0).
SetMaxHealth()	int value	Changes Max Health at runtime. Useful for upgrades that increase max HP.