Hasebe/Assets/Code/Infrastructure/Utils/HitBoxUtil.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering;

namespace Code.Infrastructure.Utils
{
    public static class HitBoxUtil
    {
        private struct ActiveHitbox
        {
            public Matrix4x4 Matrix;
            public Material Material;
            public float ExpireTime;
        }

        private static readonly List<ActiveHitbox> _activeBoxes = new();
        private static Mesh _unitCubeMesh;
        private static bool _isInitialized;

        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
        private static void Initialize()
        {
            if (_isInitialized) return;

            _unitCubeMesh = CreateUnitCubeMesh();

            // Подписываемся на этап рендера для отрисовки в каждом кадре
            RenderPipelineManager.beginContextRendering += OnBeginContextRendering;
            UnityEngine.Camera.onPreCull += OnPreCullLegacy;

            _isInitialized = true;
        }

        /// <summary>
        /// Добавляет хитбокс на заданную длительность (в секундах)
        /// </summary>
        public static void DrawBox(Vector3 center, Vector3 size, Quaternion rotation, Material material,
            float duration = 1.0f)
        {
            if (material == null || _unitCubeMesh == null) return;

            Matrix4x4 trs = Matrix4x4.TRS(center, rotation, size);

            _activeBoxes.Add(new ActiveHitbox
            {
                Matrix = trs,
                Material = material,
                ExpireTime = Time.unscaledTime + duration
            });
        }

        /// <summary>
        /// Перегрузка напрямую для BoxCollider
        /// </summary>
        public static void DrawBoxCollider(BoxCollider box, Material material, float duration = 1.0f)
        {
            if (box == null) return;

            Transform t = box.transform;
            Vector3 center = t.TransformPoint(box.center);
            Vector3 size = Vector3.Scale(box.size, t.lossyScale);

            DrawBox(center, size, t.rotation, material, duration);
        }

        /// <summary>
        /// Мгновенная очистка всех активных хитбоксов (например, при выходе из боя)
        /// </summary>
        public static void Clear()
        {
            _activeBoxes.Clear();
        }

        private static void OnBeginContextRendering(ScriptableRenderContext context, List<UnityEngine.Camera> cameras)
        {
            RenderHitboxes();
        }

        private static void OnPreCullLegacy(UnityEngine.Camera cam)
        {
            // Для совместимости с Built-in RP
            if (GraphicsSettings.currentRenderPipeline == null)
            {
                RenderHitboxes();
            }
        }

        private static void RenderHitboxes()
        {
            if (_activeBoxes.Count == 0) return;

            float currentTime = Time.unscaledTime;

            for (int i = _activeBoxes.Count - 1; i >= 0; i--)
            {
                ActiveHitbox box = _activeBoxes[i];

                if (currentTime >= box.ExpireTime)
                {
                    _activeBoxes.RemoveAt(i);
                    continue;
                }

                // Отправляем GPU команду на отрисовку процедурного меша куба
                Graphics.DrawMesh(
                    _unitCubeMesh,
                    box.Matrix,
                    box.Material,
                    0, // Layer
                    null, // Camera (null = все камеры)
                    0, // Submesh index
                    null, // MaterialPropertyBlock
                    castShadows: false,
                    receiveShadows: false,
                    useLightProbes: false
                );
            }
        }

        /// <summary>
        /// Генерирует единичный куб 1x1x1 от -0.5 до 0.5 без создания лишних GameObject
        /// </summary>
        private static Mesh CreateUnitCubeMesh()
        {
            Mesh mesh = new Mesh { name = "Procedural_Unit_Cube" };

            Vector3[] vertices =
            {
                new(-0.5f, -0.5f, -0.5f), new(0.5f, -0.5f, -0.5f), new(0.5f, 0.5f, -0.5f), new(-0.5f, 0.5f, -0.5f),
                new(-0.5f, -0.5f, 0.5f), new(0.5f, -0.5f, 0.5f), new(0.5f, 0.5f, 0.5f), new(-0.5f, 0.5f, 0.5f)
            };

            int[] triangles =
            {
                // Задняя
                0, 2, 1, 0, 3, 2,
                // Передняя
                4, 5, 6, 4, 6, 7,
                // Левая
                0, 7, 3, 0, 4, 7,
                // Правая
                1, 2, 6, 1, 6, 5,
                // Нижняя
                0, 1, 5, 0, 5, 4,
                // Верхняя
                3, 6, 2, 3, 7, 6
            };

            mesh.vertices = vertices;
            mesh.triangles = triangles;
            mesh.RecalculateNormals();
            mesh.RecalculateBounds();

            return mesh;
        }
    }
}