BlockBreakerRogueLite/Assets/Scripts/BallEffects/TripleSplitEffect.cs

using UnityEngine;

public class TripleSplitEffect : BallEffectBase
{
    private bool _hasSplit;
    private TripleSplitEffectDefinition Config => definition as TripleSplitEffectDefinition;

    public override void OnBallReset(BallScript ball)
    {
        _hasSplit = false;
    }

    public override void OnHitBlock(BallScript ball, blockScript block, Collision2D collision)
    {
        TripleSplitEffectDefinition config = Config;
        if (config == null)
            return;

        if (config.SplitOnlyOnce && _hasSplit)
            return;

        _hasSplit = true;

        Vector2 currentDir = collision.rigidbody != null
            ? collision.rigidbody.linearVelocity.normalized
            : Vector2.up;

        // Spawn two additional balls at +/- splitAngle around current direction.
        Vector2 dirA = Rotate(currentDir, config.SplitAngle);
        Vector2 dirB = Rotate(currentDir, -config.SplitAngle);
        BallScript cloneA = ball.SpawnClone(dirA, config.ChildSpeedMultiplier, config.ChildScaleMultiplier, config.ChildDamageMultiplier);
        BallScript cloneB = ball.SpawnClone(dirB, config.ChildSpeedMultiplier, config.ChildScaleMultiplier, config.ChildDamageMultiplier);

        // The original ball becomes one of the 3 child balls.
        ball.MultiplyScale(config.ChildScaleMultiplier);
        ball.MultiplyDamage(config.ChildDamageMultiplier);

        if (config.SplitOnlyOnce)
        {
            MarkAsAlreadySplit(cloneA);
            MarkAsAlreadySplit(cloneB);
        }
    }

    private static void MarkAsAlreadySplit(BallScript cloneBall)
    {
        if (cloneBall == null)
            return;

        TripleSplitEffect cloneEffect = cloneBall.GetComponent<TripleSplitEffect>();
        if (cloneEffect != null)
            cloneEffect._hasSplit = true;
    }

    private static Vector2 Rotate(Vector2 v, float degrees)
    {
        float rad = degrees * Mathf.Deg2Rad;
        float sin = Mathf.Sin(rad);
        float cos = Mathf.Cos(rad);
        return new Vector2(v.x * cos - v.y * sin, v.x * sin + v.y * cos).normalized;
    }
}