Build the HUD

Complete Add Mineral Income first. This HUD displays the local balance, selection, health, and actions. It will also show production abilities when you add buildings.

1. Create the layout

Create Content/Demo/Blueprints/UI. Create a Widget Blueprint with parent SeinUserWidget, named WBP_DemoHUD.

In its Designer, add a Canvas Panel root. Set its visibility to Not Hit-Testable (Self Only) so unused screen space still accepts world clicks. Add:

Widget	Name	Placement
Text Block	MineralsText	Top-left, offset (24, 24)
Vertical Box	SelectionPanel	Bottom-left, offset from the bottom (24, -200)
Text Block inside SelectionPanel	SelectionName	First child
Progress Bar inside SelectionPanel	HealthBar	Second child
Wrap Box inside SelectionPanel	ActionButtons	Third child

Use bottom-left anchors and alignment (0, 1) for SelectionPanel. Give it a width around 420 and enable Size To Content vertically. Mark the named widgets Is Variable. Compile and save.

2. Show the HUD

Open PC_DemoSkirmishController. Extend its existing local-controller BeginPlay path after input setup:

1. Create Widget of class WBP_DemoHUD, Owning Player = self.
2. Store the return value in a DemoHUD variable.
3. Call Add to Viewport on it.

Keep this inside the Is Local Controller branch. Each player creates their own HUD. Compile and save.

3. Read Minerals and selection

In WBP_DemoHUD, create a function named RefreshHUD. The following functions are supplied by its SeinUserWidget parent.

Call Get Local Player View Model. If valid, call its Get Resource with SeinARTS.Resource.Minerals, format the returned number without fractional digits, and set MineralsText to Minerals: {value} using Format Text.

Call Get Selection Model, then Get Primary View Model. If there is no valid primary model, collapse SelectionPanel and return. Otherwise show the panel and set SelectionName from the model’s Display Name.

Call Has Component on the primary model with the generated health data struct. If true, read Health and MaxHealth through the model’s Get Base Attribute function. Set HealthBar Percent to Health / MaxHealth, clamped to 0..1; use zero if MaxHealth is not positive. Hide HealthBar for entities without this component.

Call RefreshHUD from the widget’s Event Tick. This tick only reads presentation data and updates widgets. The combat and income loops continue to run exclusively in ability simulation callbacks.

4. Create an ability button

Create another SeinUserWidget Blueprint, WBP_AbilityButton. Its Designer contains a Button named ActionButton with a Text Block child named ActionLabel.

Add a Gameplay Tag variable named AbilityTag, marked Instance Editable and Expose on Spawn. Compile.

Create RefreshButton:

1. Get Selection Model and call Get Selection Ability By Tag, passing AbilityTag.
2. Break the returned Ability Info. Set ActionLabel from Name.
3. Set ActionButton’s Is Enabled from Is Enabled in Ability Info.
4. Set its tooltip text from Format Resource Cost on Resource Cost. When disabled, append the Disabled Reason converted to text.

Call RefreshButton from Event Tick. On ActionButton On Clicked, call Trigger Ability From Action Slot with the cached Sein Player Controller and AbilityTag. This either submits an untargeted action or starts the appropriate world targeter.

Compile and save.

5. Populate the action panel

Back in WBP_DemoHUD, add a Gameplay Tag array variable named DisplayedAbilityTags.

Extend RefreshHUD after selection handling:

1. Call Get Selection Abilities on the selection model.
2. Build a local Gameplay Tag array from the returned entries, skipping entries whose Is Passive is true.
3. Compare this array with DisplayedAbilityTags. If equal, keep the existing buttons.
4. Otherwise, Clear Children on ActionButtons and replace DisplayedAbilityTags with the new array.
5. For each tag, Create Widget WBP_AbilityButton, with the HUD’s owning player and the exposed AbilityTag. Add Child to Wrap Box on ActionButtons.

In the no-selection branch, clear ActionButtons and DisplayedAbilityTags as well as collapsing the panel. Rebuilding only when the tag list changes preserves button presses while availability and cooldown values refresh.

Compile and save.

6. Test the HUD

Run Play Standalone:

1. Check Minerals starts at 500.
2. Select the Soldier. Its name, full health bar, and Move, Attack, and Harvest buttons appear.
3. Click Harvest, then confirm the nearby deposit with the world targeter. Each hit grants 3 Minerals, or the remaining stock if less than 3 remains.
4. Repeat the deposit test with Remaining 25. The final balance should be 525 and the deposit should disappear.
5. Deselect everything. The selection panel should clear while Minerals remains visible.
6. Drag a selection marquee over empty HUD space. The full-screen Canvas should not consume the drag.

Checkpoint

• A local controller creates its HUD once.
• Resource and health displays read UI models.
• Buttons reflect the selection’s current grants and availability.
• Ability clicks go through Trigger Ability From Action Slot.

Continue with Build Production Buildings.