TO SQUASH: Nuke ball explosion.

Assets/Scripts/Game/Balls/BallBase.cs

@@ -199,4 +199,9 @@ public class BallBase : MonoBehaviour
         bounds = default;
         return false;
     }
+
+    public void StopBall()
+    {
+        speed = new Vector2(0.0f, 0.0f);
+    }
 }

Assets/Scripts/Game/Balls/NukeBall.cs

@@ -1,4 +1,6 @@
 using UnityEngine;
+using System.Collections;
+using System.Collections.Generic;
 
 public class NukeBall : BallBase
 {
@@ -6,6 +8,8 @@ public class NukeBall : BallBase
 
     public AudioClip explosionSound;
 
+    public GameObject explosionEffectPrefab;
+
     public WorldFiller worldFiller;
 
     // Tracks escalating danger/critical phases for audio cues.
@@ -30,6 +34,8 @@ public class NukeBall : BallBase
 
     private float bounceDuration = 1.00f;
 
+    private bool exploding = false;
+
     // Start is called once before the first execution of Update after the MonoBehaviour is created
     void Start()
     {
@@ -55,6 +61,11 @@ public class NukeBall : BallBase
     // Update is called once per frame
     void FixedUpdate()
     {
+        if (exploding)
+        {
+            return;
+        }
+
         AnimatorStateInfo stateInfo = animator.GetCurrentAnimatorStateInfo(0);
 
         if (stateInfo.IsName("NuclearBallBounce")) {
@@ -100,14 +111,20 @@ public class NukeBall : BallBase
     {
         // Set critical state.
         var area = worldFiller != null ? worldFiller.GetAreaPercentOfFreeRegion(transform.position) : -1.0f;
-        criticalState = (area < 0.2f) ? 2 : (area < 0.4f) ? 1 : 0;
+
+        if (area == -1.0f || exploding)
+        {
+            return;
+        }
+
+        criticalState = (area < 0.12f) ? 3 : (area < 0.2f) ? 2 : (area < 0.4f) ? 1 : 0;
 
         // State 1 beeps every 0.5s, state 2 beeps every 0.25s.
         criticalTime = (criticalState == 2) ? 0.5f : 1.0f;
 
         // If in a critical state, increment the critical timer and play the
         // critical sound if the timer exceeds the critical time.
-        if (criticalState >= 1)
+        if (criticalState == 1 || criticalState == 2)
         {
             criticalTimer += Time.deltaTime;
 
@@ -119,6 +136,28 @@ public class NukeBall : BallBase
                 criticalTimer -= criticalTime;
             }
         }
+        else if (criticalState == 3)
+        {
+            audioSource.PlayOneShot(explosionSound);
+
+            var balls = worldFiller != null ? 
+                worldFiller.GetBallsInSameFreeRegion(transform.position) :
+                new Queue<GameObject>();
+
+            foreach (var ball in balls)
+            {
+                ball.GetComponent<BallBase>()?.StopBall();
+
+                if (explosionEffectPrefab != null)
+                {
+                    Instantiate(explosionEffectPrefab, ball.transform.position, Quaternion.identity);
+                }
+            }
+
+            exploding = true;
+
+            StartCoroutine(DestroyAndFillRegion(balls));
+        }
         else
         {
             criticalTimer = 0.0f;
@@ -198,4 +237,25 @@ public class NukeBall : BallBase
             }
         }
     }
+
+    private IEnumerator DestroyAndFillRegion(Queue<GameObject> balls)
+    {
+        yield return new WaitForSeconds(1.4f);
+
+        foreach (var ball in balls)
+        {
+            Destroy(ball);
+        }
+
+        var freeRegion = worldFiller != null ? 
+            worldFiller.GetFreeRegionOfPosition(transform.position) :
+            null;
+
+        if (freeRegion != null)
+        {
+            worldFiller.FillFreeRegion(freeRegion.Value);
+        }
+
+        Destroy(gameObject);
+    }
 }

Assets/Scripts/Game/WorldFiller.cs

@@ -9,6 +9,12 @@ public class WorldFiller : MonoBehaviour
 
     public GameObject wallPrefab;
 
+    public BallSpawner ballSpawner;
+
+    public AudioClip areaDestroyed;
+
+    private AudioSource audioSource;
+
     [SerializeField]
     private float fallbackBarThicknessWorldUnits = 0.08f;
 
@@ -33,6 +39,7 @@ public class WorldFiller : MonoBehaviour
     // Start is called once before the first execution of Update after the MonoBehaviour is created
     void Start()
     {
+        audioSource = GetComponent<AudioSource>();
         gameBoardBounds = gameBoardSpriteRenderer.bounds;
         InitializeFreeAreas();
         ClearWalls();
@@ -299,7 +306,7 @@ public class WorldFiller : MonoBehaviour
         return false;
     }
 
-public float GetAreaPercentOfFreeRegion(Vector2 position)
+    public float GetAreaPercentOfFreeRegion(Vector2 position)
     {
         if (freeAreas.Count == 0 && gameBoardSpriteRenderer != null)
         {
@@ -317,6 +324,75 @@ public float GetAreaPercentOfFreeRegion(Vector2 position)
         return -1.0f;
     }
 
+    public Rect? GetFreeRegionOfPosition(Vector2 position)
+    {
+        if (freeAreas.Count == 0 && gameBoardSpriteRenderer != null)
+        {
+            InitializeFreeAreas();
+        }
+
+        for (int i = 0; i < freeAreas.Count; i++)
+        {
+            if (RectContainsWithTolerance(freeAreas[i], position))
+            {
+                return freeAreas[i];
+            }
+        }
+
+        return null;
+    }
+
+    public bool FillFreeRegion(Rect freeRegion)
+    {
+        if ((freeAreas.Count == 0 || boardArea <= geometryEpsilon) && gameBoardSpriteRenderer != null)
+        {
+            InitializeFreeAreas();
+        }
+
+        if (!TryGetMatchingFreeArea(freeRegion, out Rect regionToFill))
+        {
+            Debug.LogWarning("Requested region is not currently a free area.");
+            return false;
+        }
+
+        if (!TrySpawnWallInRect(regionToFill))
+        {
+            return false;
+        }
+
+        audioSource.PlayOneShot(areaDestroyed);
+
+        return true;
+    }
+
+    public Queue<GameObject> GetBallsInSameFreeRegion(Vector2 position)
+    {
+        Queue<GameObject> ballsInSameRegion = new Queue<GameObject>();
+
+        if (ballSpawner == null)
+        {
+            return ballsInSameRegion;
+        }
+
+        var targetRegion = GetFreeRegionOfPosition(position);
+
+        if (targetRegion == null)
+        {
+            return ballsInSameRegion;
+        }
+
+        foreach (var ball in ballSpawner.GetBalls())
+        {
+            var ballRegion = GetFreeRegionOfPosition(ball.transform.position);
+            if (ballRegion != null && ballRegion.Value == targetRegion.Value)
+            {
+                ballsInSameRegion.Enqueue(ball);
+            }
+        }
+
+        return ballsInSameRegion;
+    }
+
     public Vector2 GetRandomPositionInFreeAreas(Bounds? clearingArea = null)
     {
         if (freeAreas.Count == 0 && gameBoardSpriteRenderer != null)
@@ -531,6 +607,180 @@ public float GetAreaPercentOfFreeRegion(Vector2 position)
         }
     }
 
+    private bool TryGetMatchingFreeArea(Rect requestedRegion, out Rect matchedRegion)
+    {
+        for (int i = 0; i < freeAreas.Count; i++)
+        {
+            if (RectsApproximatelyEqual(freeAreas[i], requestedRegion))
+            {
+                matchedRegion = freeAreas[i];
+                return true;
+            }
+        }
+
+        matchedRegion = default;
+        return false;
+    }
+
+    private bool RectsApproximatelyEqual(Rect a, Rect b)
+    {
+        return Mathf.Abs(a.xMin - b.xMin) <= geometryEpsilon
+            && Mathf.Abs(a.yMin - b.yMin) <= geometryEpsilon
+            && Mathf.Abs(a.xMax - b.xMax) <= geometryEpsilon
+            && Mathf.Abs(a.yMax - b.yMax) <= geometryEpsilon;
+    }
+
+    private bool TrySpawnWallInRect(Rect targetRect)
+    {
+        if (wallPrefab == null)
+        {
+            Debug.LogError("Wall prefab is not assigned.");
+            return false;
+        }
+
+        if (gameBoardSpriteRenderer == null)
+        {
+            Debug.LogError("Game board SpriteRenderer is not assigned.");
+            return false;
+        }
+
+        gameBoardBounds = gameBoardSpriteRenderer.bounds;
+
+        Rect boardRect = Rect.MinMaxRect(
+            gameBoardBounds.min.x,
+            gameBoardBounds.min.y,
+            gameBoardBounds.max.x,
+            gameBoardBounds.max.y
+        );
+
+        if (!TryGetRectIntersection(targetRect, boardRect, out Rect clampedRect))
+        {
+            Debug.LogWarning("Target wall rectangle is outside the game board bounds.");
+            return false;
+        }
+
+        GameObject wall = Instantiate(wallPrefab, Vector3.zero, Quaternion.identity);
+        var wallRenderer = wall.GetComponentInChildren<SpriteRenderer>();
+
+        if (wallRenderer == null)
+        {
+            Debug.LogError("Wall prefab is missing a SpriteRenderer in children.");
+            Destroy(wall);
+            return false;
+        }
+
+        float wallPaddingWorldUnits = PixelsToWorldUnits(wallPaddingPixelsPerSide, wallRenderer);
+        Rect paddedWallRect = ExpandRectInsideBounds(clampedRect, wallPaddingWorldUnits, boardRect);
+
+        ApplyWallTransform(wall.transform, wallRenderer, paddedWallRect);
+        spawnedWalls.Enqueue(wall);
+
+        UpdateFreeAreas(paddedWallRect);
+        ResolveWallIntersections(wallRenderer.bounds);
+        DestroyBarSegments();
+
+        if (boardArea <= geometryEpsilon)
+        {
+            boardArea = boardRect.width * boardRect.height;
+        }
+
+        int areaPercentage = boardArea > geometryEpsilon
+            ? Mathf.RoundToInt((paddedWallRect.width * paddedWallRect.height / boardArea) * 100.0f)
+            : 0;
+
+        if (player != null)
+        {
+            player.OnWallSpawned(areaPercentage);
+        }
+
+        return true;
+    }
+
+    private void ResolveWallIntersections(Bounds wallBounds)
+    {
+        // Yummies and multipliers are awarded if intersected by the spawned wall.
+        var yummies = GameObject.FindGameObjectsWithTag("Yummy");
+        var multipliers = GameObject.FindGameObjectsWithTag("Multiplier");
+        var shark = GameObject.FindGameObjectWithTag("Shark");
+
+        foreach (var yummy in yummies)
+        {
+            if (yummy == null)
+            {
+                continue;
+            }
+
+            var yummyRenderer = yummy.GetComponent<SpriteRenderer>();
+            if (yummyRenderer == null || !wallBounds.Intersects(yummyRenderer.bounds))
+            {
+                continue;
+            }
+
+            YummyBase yummyBase = yummy.GetComponent<YummyBase>();
+
+            if (yummyBase != null)
+            {
+                yummyBase.AwardToPlayer(player);
+            }
+            else
+            {
+                Debug.LogError("YummyBase component not found on yummy object.");
+            }
+        }
+
+        foreach (var multiplier in multipliers)
+        {
+            if (multiplier == null)
+            {
+                continue;
+            }
+
+            var multiplierRenderer = multiplier.GetComponent<SpriteRenderer>();
+            if (multiplierRenderer == null || !wallBounds.Intersects(multiplierRenderer.bounds))
+            {
+                continue;
+            }
+
+            Multiplier multiplierComponent = multiplier.GetComponent<Multiplier>();
+
+            if (multiplierComponent != null)
+            {
+                multiplierComponent.AwardToPlayer(player);
+            }
+            else
+            {
+                Debug.LogError("Multiplier component not found on multiplier object.");
+            }
+        }
+
+        if (shark == null)
+        {
+            return;
+        }
+
+        var sharkRenderer = shark.GetComponent<SpriteRenderer>();
+        if (sharkRenderer == null || !wallBounds.Intersects(sharkRenderer.bounds))
+        {
+            return;
+        }
+
+        Shark sharkComponent = shark.GetComponent<Shark>();
+        if (sharkComponent != null)
+        {
+            sharkComponent.KillShark();
+        }
+    }
+
+    private void DestroyBarSegments()
+    {
+        GameObject[] barSegments = GameObject.FindGameObjectsWithTag("Bar");
+
+        foreach (GameObject barSegment in barSegments)
+        {
+            Destroy(barSegment);
+        }
+    }
+
     private void ApplyWallTransform(Transform wallTransform, SpriteRenderer wallRenderer, Rect targetRect)
     {
         Vector2 baseSize = wallRenderer.bounds.size;