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

// 给每个角色准备一些特殊的前置渲染
public class UnitPreprocessing : UnitComponent
{
	[Flags]
	public enum EUnitPreprocessing
	{
		None ,
		DepthTexture,       // Unit Depth Texture
		WorldNormalTexture, // Unit World Normal Texture
	}

	public EUnitPreprocessing preprocessing;

	public RenderTexture unitDepthTexture { get; private set; }
	public RenderTexture unitWorldNormalTexture { get; private set; }

	private CommandBuffer m_CBBeforeDepthTexture;

	private Material m_MaterialDepth;

	public override void Initialize()
	{
		base.Initialize();
	}

	public override void OnPostInitialize()
	{
		base.OnPostInitialize();

		MainCamera.Instance.customRenderingPipeline.onPreCull += OnWillRenderUnit;
		MainCamera.Instance.customRenderingPipeline.onPostRender += OnRenderUnit;

		m_CBBeforeDepthTexture = new CommandBuffer();

		PrepareRenderTextures();
		PrepareMaterials();
	}

	void PrepareRenderTextures()
	{
		int unitHash = owner.GetHashCode();

		int width = MainCamera.Instance.camera.pixelWidth;
		int height = MainCamera.Instance.camera.pixelHeight;
		unitDepthTexture = new RenderTexture(width, height, 24, RenderTextureFormat.Depth, RenderTextureReadWrite.Linear);
		unitDepthTexture.name = "UnitDepthTexture_" + owner.GetHashCode();
	}

	void PrepareMaterials()
	{
		m_MaterialDepth = new Material(Shader.Find(StaticDefine.shaders[EShader.UnitDepth].name));
	}

	public override void OnUpdate()
	{
		base.OnUpdate();
	}

	public override void Release()
	{
		MainCamera.Instance.customRenderingPipeline.onPreCull -= OnWillRenderUnit;
		MainCamera.Instance.customRenderingPipeline.onPostRender -= OnRenderUnit;

		base.Release();
	}

	private void OnWillRenderUnit()
	{
		RenderDepthTexture();
		//RenderWorldNormal();

		MainCamera.Instance.camera.AddCommandBuffer(CameraEvent.BeforeDepthTexture, m_CBBeforeDepthTexture);
	}

	void RenderDepthTexture()
	{
		var cb = m_CBBeforeDepthTexture;
		cb.Clear();
		cb.SetRenderTarget(unitDepthTexture);
		cb.ClearRenderTarget(true, true, new Color(0, 0, 0, 0));

		cb.SetGlobalVector("unity_LightShadowBias", Vector4.zero);

		foreach (var r in GetRenderers())
		{
			BodyPartRenderer br = r as BodyPartRenderer;
			if (br == null)
				continue;
			Renderer renderer = br.renderer as Renderer;
			if (renderer == null)
				continue;
			cb.DrawRenderer(renderer, m_MaterialDepth);
		}
	}

	//void RenderWorldNormal()
	//{
	//	var cb = m_CBBeforeDepthTexture;
	//	cb.Clear();
	//	cb.GetTemporaryRT(unitWorldNormalTextureID, -1, -1, 24, FilterMode.Point, RenderTextureFormat.RG16, RenderTextureReadWrite.Linear);
	//	cb.SetRenderTarget(unitWorldNormalTextureID);
	//	cb.ClearRenderTarget(true, true, new Color(0, 0, 0, 0));
	//}

	IEnumerable GetRenderers()
	{
		IBodyRendererAgent body = owner.unitRender.body;
		if (body == null || body.renderers == null || body.renderers.Length == 0)
			yield break;
		for (int j = 0; j < body.renderers.Length; ++j)
		{
			yield return body.renderers[j];
		}
	}

	private void OnRenderUnit()
	{
		//m_CBBeforeDepthTexture.ReleaseTemporaryRT(unitDepthTextureID);

		MainCamera.Instance.camera.RemoveCommandBuffer(CameraEvent.BeforeDepthTexture, m_CBBeforeDepthTexture);
	}
}