using System;
using UnityEngine;

namespace Thousandto.Plugins.Common.UniScene
{
    //摄像机混合脚本
    public class CameraBlendRender : MonoBehaviour
    {
        #region//私有变量
        private float _blendTime = 1f;
        private float _timer = 0f;
        private Action _finishCallBack = null;
        private Shader _shader = null;
        private Material _material = null;
        private Camera _targetCamera = null;
        private RenderTexture _targetTex = null;
        #endregion

        #region//公有函数
        public void PlayBlend(Camera target, float time, Action finishCallBack)
        {
            if(_shader == null)
            {
                _shader = Core.Base.ShaderEx.Find("Ares/Camera/CameraBlendPass");
            }
            if(_material == null)
            {
                _material = new Material(_shader);
            }
            _timer = 0f;
            _blendTime = time;
            if(_targetCamera != null)
            {
                _targetCamera.targetTexture = null;
            }
            if(_targetTex == null)
            {
                _targetTex = RenderTexture.GetTemporary(Screen.width, Screen.height, 24, RenderTextureFormat.ARGB32);
                _targetTex.name = "RenderTexture9";
                _targetTex.antiAliasing = 1;
            }
            _targetCamera = target;
            _targetCamera.targetTexture = _targetTex;
            //渲染一次，防止出现白色
            _targetCamera.Render();
            _finishCallBack = finishCallBack;
            Update();
        }
        #endregion

        #region//脚本函数
        private void Update()
        {
            _timer += Time.deltaTime;
            _material.SetTexture("_TargetText", _targetTex);
            _material.SetFloat("_LerpValue", _timer / _blendTime);
            if (_timer >= _blendTime)
            {
                _finishCallBack();
            }
            //同步摄像机位置，防止重影
            _targetCamera.transform.localPosition = transform.localPosition;
        }
        private void OnRenderImage(RenderTexture source, RenderTexture destination)
        {
            Graphics.Blit(source, destination, _material);
        }
        private void OnDestroy()
        {
            GameObject.DestroyImmediate(_material);
            RenderTexture.ReleaseTemporary(_targetTex);
            _targetCamera.targetTexture = null;
        }
        #endregion
    }
}