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

public class Blur : ScriptableRendererFeature
{
    class BlurRenderPass : ScriptableRenderPass
    {
        private Material material;
        private BlurSettings settings;

        private RenderTargetIdentifier source;
        private RenderTargetHandle mainTex;
        private RenderTargetHandle blurTex;
        private string profilerTag;

        public BlurRenderPass(string profilerTag)
        {
            this.profilerTag = profilerTag;
        }

        public void Setup(ScriptableRenderer renderer)
        {
            source = renderer.cameraColorTarget;
            settings = VolumeManager.instance.stack.GetComponent<BlurSettings>();
            renderPassEvent = RenderPassEvent.BeforeRenderingPostProcessing;

            if(settings != null && settings.IsActive())
            {
                renderer.EnqueuePass(this);
                material = new Material(Shader.Find("SnapshotProURP/Blur"));
            }
        }

        public override void Configure(CommandBuffer cmd, RenderTextureDescriptor cameraTextureDescriptor)
        {
            if(settings == null)
            {
                return;
            }

            mainTex = new RenderTargetHandle();
            mainTex.id = Shader.PropertyToID("_MainTex");
            cmd.GetTemporaryRT(mainTex.id, cameraTextureDescriptor);

            blurTex = new RenderTargetHandle();
            blurTex.id = Shader.PropertyToID("_BlurTex");
            cmd.GetTemporaryRT(blurTex.id, cameraTextureDescriptor);

            base.Configure(cmd, cameraTextureDescriptor);
        }

        public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
        {
            if(!settings.IsActive())
            {
                return;
            }

            CommandBuffer cmd = CommandBufferPool.Get(profilerTag);

            // Copy camera color texture to mainTex.
            cmd.Blit(source, mainTex.id);

            // Set Blur effect properties.
            cmd.SetGlobalInt("_KernelSize", settings.strength.value);
            cmd.SetGlobalFloat("_Spread", settings.strength.value / 7.5f);

            // Execute effect using effect material with two passes.
            cmd.Blit(mainTex.id, blurTex.id, material, 0);
            cmd.Blit(blurTex.id, source, material, 1);

            context.ExecuteCommandBuffer(cmd);
            cmd.Clear();
            CommandBufferPool.Release(cmd);
        }

        public override void FrameCleanup(CommandBuffer cmd)
        {
            cmd.ReleaseTemporaryRT(mainTex.id);
            cmd.ReleaseTemporaryRT(blurTex.id);
        }
    }

    BlurRenderPass pass;

    public override void Create()
    {
        pass = new BlurRenderPass("Blur");
        name = "Blur";
    }

    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
    {
        pass.Setup(renderer);
    }
}
