✨Feature: scripts to handle user life UI

Assets/Scripts/UI/Lifebar/Heart.cs

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+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.UIElements;
+
+// This is the heart of the Lifebar_UI
+// The Heart have the 'heart' uss StyleSheet and an icon ( empty, half or full heart sprite)
+public class Heart : VisualElement
+{
+    public Heart(Sprite icon)
+    {
+        AddToClassList("heart");                                // Add the '.heart' uss styles
+        UpdateIcon(icon);
+    }
+
+    public void UpdateIcon(Sprite icon)
+    {
+        this.style.backgroundImage = new StyleBackground(icon); // Add the heart icon
+    }
+}

Assets/Scripts/UI/Lifebar/LifebarWindow.cs

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+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.UIElements;
+using Gameplay;
+
+public class LifebarWindow : MonoBehaviour
+{
+    [SerializeField] private UIDocument _UIDocument;
+    [SerializeField] private Sprite _emptyHeart;
+    [SerializeField] private Sprite _halfHeart;
+    [SerializeField] private Sprite _fullHeart;
+
+    /* CONSTANTS */
+    private const int EMPTY_HEART = 0;
+    private const int HALF_HEART = 1;
+    private const int FULL_HEART = 2;
+    private const int HEARTS_PER_LINE = 10;
+    private const int HEARTS_TO_SECOND_LINE = 10;
+    private const int FIRST_LINE = 0;
+    private const int SECOND_LINE = 1;
+
+    private VisualElement _root;
+    private VisualElement _firstLine;
+    private VisualElement _secondLine;
+
+    private List<Heart> _hearts = new List<Heart>();// Store a list of hearts, showed in the Lifebar_UI
+    private int _currentHeartIndex = 0;             // The last non empty heart on the list of hearts
+    private int _currentHeartLine = FIRST_LINE;     // The line of the last non-empty heart on the list of hearts
+    private int _currentHeartState = EMPTY_HEART;   // The state of the last non-empty heart on the list of hearts
+
+    void Awake()
+    {
+        PlayerHealth.InitializePlayerHealthEvent += UI_SetMaxLife;
+        PlayerHealth.PlayerTakeDamageEvent += UI_TakeDamage;
+        PlayerHealth.PlayerTakeHealEvent += UI_TakeHeal;
+        _root = _UIDocument.rootVisualElement;
+        _firstLine = _root.Q<GroupBox>("first-line");
+        _secondLine = _root.Q<GroupBox>("second-line");
+    }
+
+    private void PrintHeartState()
+    {
+        Debug.Log("INDEX: " + _currentHeartIndex);
+        Debug.Log("LINE: " + _currentHeartLine);
+        Debug.Log("HEART_STATE: " + _currentHeartState);
+    }
+
+     // Creates a 'VisualElement' Heart and add it to the life bar and the list of hearts
+    private void CreateHeart()
+    {
+        // Create a Heart with its right icon and uss and add to the list of hearts
+        Heart heart = new Heart(_fullHeart);
+        _hearts.Add(heart);
+
+        // Add the heart accordly to the line in the Lifebar UI
+        switch (_currentHeartLine)
+        {
+            case FIRST_LINE:
+                _firstLine.Add(heart);
+                break;
+            case SECOND_LINE:
+                _secondLine.Add(heart);
+                break;
+        }
+
+        // Update the heart if the maximum heart by line were achieved
+        if (_hearts.Count >= HEARTS_TO_SECOND_LINE)
+        {
+            _currentHeartLine = SECOND_LINE;
+        }
+    }
+
+    // Sets the max number of hearts to the life bar
+    public void UI_SetMaxLife(int maxLife)
+    {
+        int correctLife = maxLife;     
+        for (int i = 0; i < correctLife; i += 2)
+        {
+            CreateHeart();
+        }
+
+        _currentHeartIndex = _hearts.Count - 1;
+        if (correctLife % FULL_HEART == 1)
+        {
+            _currentHeartState = HALF_HEART;
+            _hearts[_currentHeartIndex].UpdateIcon(_halfHeart);
+        }
+        else
+        {
+            _currentHeartState = FULL_HEART;
+        }
+        //PrintHeartState();
+    }
+
+    // Fill hearts in the Lifebar_UI, between two given indexes, with the given 'heartSprite' sprite
+    private void FillHeart(int indexFrom, int indexTo, Sprite heartSprite)
+    {
+        if (indexFrom < 0)
+        {
+            indexFrom = 0;
+        }
+        else if (indexTo > _hearts.Count)
+        {
+            indexTo = _hearts.Count;
+        }
+        else if (indexFrom > _hearts.Count)
+        {
+            return;
+        }
+        for (int i = indexFrom; i < indexTo; i++)
+        {
+            _hearts[i].UpdateIcon(heartSprite);
+        }
+    }
+
+
+    // Updates the lifebar UI according to the damage taken by the player
+    // OBS: 1 Damage equals to half heart, and 2 is a full heart of damage
+    private void UI_TakeDamage(int damage)
+    {
+        int numberOfHeartsDestroyed = damage / 2; // One heart stores 2 hitpoints, so it convert damagepoits to hearts destroyed
+
+        // Updates the Lifebar_UI accordly to the number of hearts damaged
+        FillHeart(_currentHeartIndex - numberOfHeartsDestroyed + 1, _currentHeartIndex + 1, _emptyHeart);
+
+        _currentHeartIndex -= numberOfHeartsDestroyed;  // Updates the current heart index                
+        if (_currentHeartIndex < 0)
+            _currentHeartIndex = -1;
+
+        // After the number of full hearts were removed in the Lifebar_UI, it updates the heart at the current index
+        // and tests if there is a damage (1 damage = HALF_HEART damaged) that needs to be treated
+        if (_currentHeartIndex >= 0)
+        {
+            switch (_currentHeartState)
+            {
+                case HALF_HEART:
+                    if (damage % FULL_HEART == 1)
+                    {
+                        _hearts[_currentHeartIndex].UpdateIcon(_emptyHeart);
+                        _currentHeartIndex--;
+                        _currentHeartState = FULL_HEART;
+
+                        if (_hearts.Count <= HEARTS_TO_SECOND_LINE)
+                        {
+                            _currentHeartLine = FIRST_LINE;
+                        }
+                    }
+                    else
+                    {
+                        _hearts[_currentHeartIndex].UpdateIcon(_halfHeart);
+                    }
+                    break;
+                case FULL_HEART:
+                    if (damage % FULL_HEART == 1)
+                    {
+                        _hearts[_currentHeartIndex].UpdateIcon(_halfHeart);
+                        _currentHeartState = HALF_HEART;
+                    }
+                    break;
+            }
+        }
+
+        // Updates the 'current heart' line
+        if (_currentHeartIndex < HEARTS_TO_SECOND_LINE)
+            _currentHeartLine = FIRST_LINE;
+
+        //PrintHeartState();
+    }
+
+    // Similar to UI_TakeDamage, but treat healing
+    private void UI_TakeHeal(int heal)
+    {
+        int numberOfHeartsHealed = heal / 2;
+
+        FillHeart(_currentHeartIndex, _currentHeartIndex + numberOfHeartsHealed + 1, _fullHeart);
+
+        _currentHeartIndex += numberOfHeartsHealed;
+        if (_currentHeartIndex >= _hearts.Count)
+        {
+            _currentHeartIndex = _hearts.Count - 1;
+            _currentHeartState = FULL_HEART;
+        }
+
+        switch (_currentHeartState)
+        {
+            case HALF_HEART:
+                if (heal % FULL_HEART == 1)
+                {                        
+                    _hearts[_currentHeartIndex].UpdateIcon(_fullHeart);
+                    _currentHeartState = FULL_HEART;
+                }
+                else
+                {
+                    _hearts[_currentHeartIndex].UpdateIcon(_halfHeart);
+                }
+                break;
+            case FULL_HEART:
+                if (heal % FULL_HEART == 1 && _currentHeartIndex + 1 < _hearts.Count)
+                {                        
+                    _currentHeartIndex++;
+                    _hearts[_currentHeartIndex].UpdateIcon(_halfHeart);
+                    _currentHeartState = HALF_HEART;
+                }
+                break;
+        }        
+
+        if (_currentHeartIndex >= HEARTS_TO_SECOND_LINE)
+            _currentHeartLine = SECOND_LINE;
+    }
+}