using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class PosterizeRenderPassFeature : ScriptableRendererFeature
{
    class CustomRenderPass : ScriptableRenderPass
    {
        private Material _material;
        private RTHandle _tempHandle, _sourceHandle;

        private const string TempTex = "_TempTex";
        private readonly int _tempTexID = Shader.PropertyToID(TempTex);

        public CustomRenderPass(Material material)
        {
            _material = material;
        }

        public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
        {
            _sourceHandle = renderingData.cameraData.renderer.cameraColorTargetHandle;
            _tempHandle = RTHandles.Alloc(new RenderTargetIdentifier(TempTex), name: TempTex);
        }

        public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
        {
            if (_material == null)
                return;

            CommandBuffer cmd = CommandBufferPool.Get();
            var descriptor = renderingData.cameraData.cameraTargetDescriptor;
            descriptor.depthBufferBits = 0;
            cmd.GetTemporaryRT(_tempTexID, descriptor, FilterMode.Bilinear);

            Blit(cmd,_sourceHandle,_tempHandle,_material);
            Blit(cmd,_tempHandle,_sourceHandle);

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

        public override void OnCameraCleanup(CommandBuffer cmd)
        {
            _tempHandle.Release();
        }
    }

    private CustomRenderPass _pass;
    public Material material;

    public override void Create()
    {
        _pass = new CustomRenderPass(material)
        {
            renderPassEvent = RenderPassEvent.AfterRenderingOpaques
        };
    }

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