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

// See _ReadMe.txt

public class DeferredDecalSystem
{
    static DeferredDecalSystem m_Instance;
    static public DeferredDecalSystem instance {
  get {
   if (m_Instance == null)
    m_Instance = new DeferredDecalSystem();
   return m_Instance;
  }
    }

    internal HashSet<Decal> m_DecalsDiffuse = new HashSet<Decal <img rel="usm" src="/SML/angry.gif" border="0" align="absmiddle" alt=">(" /> );
    internal HashSet<Decal> m_DecalsNormals = new HashSet<Decal <img rel="usm" src="/SML/angry.gif" border="0" align="absmiddle" alt=">(" /> );
    internal HashSet<Decal> m_DecalsBoth = new HashSet<Decal <img rel="usm" src="/SML/angry.gif" border="0" align="absmiddle" alt=">(" /> );

    public void AddDecal (Decal d)
    {
  RemoveDecal (d);
  if (d.m_Kind == Decal.Kind.DiffuseOnly)
   m_DecalsDiffuse.Add (d);
  if (d.m_Kind == Decal.Kind.NormalsOnly)
   m_DecalsNormals.Add (d);
  if (d.m_Kind == Decal.Kind.Both)
   m_DecalsBoth.Add (d);
    }
    public void RemoveDecal (Decal d)
    {
  m_DecalsDiffuse.Remove (d);
  m_DecalsNormals.Remove (d);
  m_DecalsBoth.Remove (d);
    }
}

[ExecuteInEditMode]
public class DeferredDecalRenderer : MonoBehaviour
{
    public Mesh m_CubeMesh;
    private Dictionary<Camera,CommandBuffer> m_Cameras = new Dictionary<Camera,CommandBuffer <img rel="usm" src="/SML/angry.gif" border="0" align="absmiddle" alt=">(" /> );

    public void OnDisable()
    {
  foreach (var cam in m_Cameras)
  {
   if (cam.Key)
   {
    cam.Key.RemoveCommandBuffer (CameraEvent.BeforeLighting, cam.Value);
   }
  }
    }

    public void OnWillRenderObject()
    {
  var act = gameObject.activeInHierarchy && enabled;
  if (!act)
  {
   OnDisable();
   return;
  }

  var cam = Camera.current;
  if (!cam)
   return;

  CommandBuffer buf = null;
  if (m_Cameras.ContainsKey(cam))
  {
   buf = m_Cameras[cam];
   buf.Clear ();
  }
  else
  {
   buf = new CommandBuffer();
   buf.name = "Deferred decals";
   m_Cameras[cam] = buf;

   // set this command buffer to be executed just before deferred lighting pass
   // in the camera
   cam.AddCommandBuffer (CameraEvent.BeforeLighting, buf);
  }

  //@TODO: in a real system should cull decals, and possibly only
  // recreate the command buffer when something has changed.

  var system = DeferredDecalSystem.instance;

  // copy g-buffer normals into a temporary RT
  var normalsID = Shader.PropertyToID("_NormalsCopy");
  buf.GetTemporaryRT (normalsID, -1, -1);
  buf.Blit (BuiltinRenderTextureType.GBuffer2, normalsID);
  // render diffuse-only decals into diffuse channel
  buf.SetRenderTarget (BuiltinRenderTextureType.GBuffer0, BuiltinRenderTextureType.CameraTarget);
  foreach (var decal in system.m_DecalsDiffuse)
  {
   buf.DrawMesh (m_CubeMesh, decal.transform.localToWorldMatrix, decal.m_Material);
  }
  // render normals-only decals into normals channel
  buf.SetRenderTarget (BuiltinRenderTextureType.GBuffer2, BuiltinRenderTextureType.CameraTarget);
  foreach (var decal in system.m_DecalsNormals)
  {
   buf.DrawMesh (m_CubeMesh, decal.transform.localToWorldMatrix, decal.m_Material);
  }
  // render diffuse+normals decals into two MRTs
  RenderTargetIdentifier[] mrt = {BuiltinRenderTextureType.GBuffer0, BuiltinRenderTextureType.GBuffer2};
  buf.SetRenderTarget (mrt, BuiltinRenderTextureType.CameraTarget);
  foreach (var decal in system.m_DecalsBoth)
  {
   buf.DrawMesh (m_CubeMesh, decal.transform.localToWorldMatrix, decal.m_Material);
  }
  // release temporary normals RT
  buf.ReleaseTemporaryRT (normalsID);
    }
}