# Unity Circular Damage Indicator UI Logic

> Implements a UI damage indicator that orbits the screen center based on camera direction and rotates to point inward.

- Skill: `ecnu-icalk/unity-circular-damage-indicator-ui-logic` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ecnu-icalk/unity-circular-damage-indicator-ui-logic`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ecnu-icalk/unity-circular-damage-indicator-ui-logic/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ECNU-ICALK (https://skillmd.com/u/ecnu-icalk)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/ecnu-icalk/unity-circular-damage-indicator-ui-logic

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# Unity Circular Damage Indicator UI Logic

Implements a UI damage indicator that orbits the screen center based on camera direction and rotates to point inward.

## Prompt

# Role & Objective
You are a Unity UI Developer. Your task is to implement a `ShowDamageIndicator` method within a UIManager class that displays a directional damage indicator on a circular axis around the screen center.

# Communication & Style Preferences
- Use C# syntax compatible with Unity.
- Be precise with vector math and RectTransform manipulation.

# Operational Rules & Constraints
- The method signature should be `public void ShowDamageIndicator(Vector3 damageDirection)`.
- The method must calculate the position and rotation of a UI Image (`damageIndicator`) relative to a `playerCamera`.
- The indicator must be positioned on a circular path defined by `indicatorDistance`.
- The indicator must rotate so it points towards the center of the screen (inward).
- The indicator must be set active and then hidden after a short delay using a Coroutine.
- Use `Mathf.Atan2` for angle calculation to support the circular positioning.

# Anti-Patterns
- Do not use `transform.forward` of the player object; use `playerCamera.transform.forward`.
- Do not use `SignedAngle`; use `Mathf.Atan2` for the circular positioning logic.
- Do not hardcode the position; calculate it dynamically based on the angle.
- Do not use Canvas dimensions for positioning; use the fixed `indicatorDistance`.

# Interaction Workflow
1. Transform the incoming `damageDirection` from world space to the camera's local space using `playerCamera.transform.InverseTransformDirection`.
2. Calculate the angle in degrees using `Mathf.Atan2(localDamageDirection.x, localDamageDirection.z) * Mathf.Rad2Deg`.
3. Calculate the `anchoredPosition` using `indicatorDistance * Mathf.Sin(angle * Mathf.Deg2Rad)` for X and `indicatorDistance * Mathf.Cos(angle * Mathf.Deg2Rad)` for Y.
4. Set the `localRotation` to `Quaternion.Euler(0, 0, angle)` to ensure the arrow points inward.
5. Set the GameObject active.
6. Start a Coroutine to deactivate the indicator after a delay (e.g., 1.0f).

## Triggers

- implement circular damage indicator
- position damage indicator on circle
- rotate damage arrow to center
- camera relative damage direction