Unity URP Blit with comments

Blit.cs

// https://github.com/Unity-Technologies/UniversalRenderingExamples/blob/master/Assets/Scripts/Runtime/RenderPasses/Blit.cshttps://samdriver.xyz/articles/scriptableRender.html
// https://samdriver.xyz/articles/scriptableRender.html

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

namespace UnityEngine.Experimental.Rendering.Universal {
    // https://github.com/Unity-Technologies/UniversalRenderingExamples/blob/master/Assets/Scripts/Runtime/RenderPasses/Blit.cs
    // https://samdriver.xyz/articles/scriptableRender.htm
    // The "pass" is what does the actual rendering work while the "feature" is how it interfaces with the rest of the scriptable pipeline.
    public class Blit :ScriptableRendererFeature {

        // Settings, we're free to put whatever we want here, public fields will be exposed in the inspector
        [System.Serializable]
        public class BlitSettings {

            public bool isEnabled = true;
            [HideInInspector] public bool isEnabledByIntensity = true;
            [Range(0,1)] public float intensity = 0.5f;

            public RenderPassEvent Event = RenderPassEvent.AfterRenderingOpaques;

            public Material blitMaterial = null;
            public int blitMaterialPassIndex = -1;
            public Target destination = Target.Color;
            public string textureId = "_BlitPassTexture";
        }

        public enum Target {
            Color,
            Texture
        }

        // MUST be names "settings"(lowercase) to be shown in the Render Features inspector
        public BlitSettings settings = new BlitSettings();
        RenderTargetHandle m_RenderTextureHandle;

        BlitPass blitPass;

        // called when OnValidate(), OnEnable() or GUIUtility(inspector) is changed
        public override void Create() {
            var passIndex = settings.blitMaterial != null ? settings.blitMaterial.passCount - 1 : 1;
            settings.blitMaterialPassIndex = Mathf.Clamp(settings.blitMaterialPassIndex, -1, passIndex);
            blitPass = new BlitPass(settings.Event, settings.blitMaterial, settings.blitMaterialPassIndex, name);
            m_RenderTextureHandle.Init(settings.textureId);

            settings.isEnabledByIntensity = (settings.intensity > 0);
        }

        // called every frame once per camera
        public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData) {

            if(!settings.isEnabled || !settings.isEnabledByIntensity) {
                // we can do nothing this frame if we want
                return;
            }

            if(settings.blitMaterial == null) {
                Debug.LogWarningFormat("Missing Blit Material. {0} blit pass will not execute. Check for missing reference in the assigned renderer.", GetType().Name);
                return;
            }

            settings.blitMaterial.SetFloat("_Intensity", settings.intensity);

            // Gather up and pass any extra information our pass will need.
            // In this case we're getting the camera's color buffer target
            var src = renderer.cameraColorTarget;
            //var src = renderer.cameraDepth;
            var dest = (settings.destination == Target.Color) ? RenderTargetHandle.CameraTarget : m_RenderTextureHandle;
            blitPass.Setup(src, dest);

            // Ask the renderer to add our pass.
            // Could queue up multiple passes and/or pick passes to use
            renderer.EnqueuePass(blitPass);
        }

    } // public class Blit :ScriptableRendererFeature

}  // namespace UnityEngine.Experimental.Rendering.Universal