unity Shader新增

Unity C++脚本/shader/Render/GrabPassFeature.cs

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+using UnityEngine;
+using UnityEngine.Rendering;
+using UnityEngine.Rendering.Universal;
+
+/// <summary>
+/// Grab Pass 特性：将当前颜色缓冲绑定为 _CameraColorAttachmentA 供热扭曲等效果使用
+/// </summary>
+public class GrabPassFeature : ScriptableRendererFeature
+{
+    [System.Serializable]
+    public class Settings
+    {
+        public RenderPassEvent renderPassEvent = RenderPassEvent.AfterRenderingPostProcessing;
+        public string shaderTagName = "Grab";
+        public LayerMask layerMask = -1;
+        
+        [Header("性能设置")]
+        [Tooltip("采样分辨率缩放（1.0 = 全分辨率，0.5 = 半分辨率）")]
+        [Range(0.25f, 1f)]
+        public float resolutionScale = 1f;
+    }
+
+    public Settings settings = new Settings();
+    private GrabPass grabPass;
+
+    public override void Create()
+    {
+        grabPass = new GrabPass(settings);
+    }
+
+    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
+    {
+        renderer.EnqueuePass(grabPass);
+    }
+
+    protected override void Dispose(bool disposing)
+    {
+        grabPass?.Dispose();
+    }
+
+    class GrabPass : ScriptableRenderPass
+    {
+        private readonly ShaderTagId shaderTagId;
+        private FilteringSettings filteringSettings;
+        private readonly Settings settings;
+        private RTHandle tempColorTarget;
+
+        public GrabPass(Settings settings)
+        {
+            this.settings = settings;
+            renderPassEvent = settings.renderPassEvent;
+            shaderTagId = new ShaderTagId(settings.shaderTagName);
+            filteringSettings = new FilteringSettings(RenderQueueRange.transparent, settings.layerMask);
+            ConfigureInput(ScriptableRenderPassInput.Color);
+        }
+
+        public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData)
+        {
+            var descriptor = renderingData.cameraData.cameraTargetDescriptor;
+            descriptor.width = Mathf.Max(1, Mathf.CeilToInt(descriptor.width * settings.resolutionScale));
+            descriptor.height = Mathf.Max(1, Mathf.CeilToInt(descriptor.height * settings.resolutionScale));
+            descriptor.depthBufferBits = 0;
+            descriptor.msaaSamples = 1;
+
+            RenderingUtils.ReAllocateIfNeeded(ref tempColorTarget, descriptor, FilterMode.Bilinear, TextureWrapMode.Clamp, name: "_GrabPassTemp");
+        }
+
+        public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
+        {
+            if (tempColorTarget == null) return;
+
+            var cmd = CommandBufferPool.Get("Grab Pass");
+            var sourceColorTarget = renderingData.cameraData.renderer.cameraColorTargetHandle;
+
+            cmd.Blit(sourceColorTarget.nameID, tempColorTarget.nameID);
+            cmd.SetGlobalTexture("_CameraColorAttachmentA", tempColorTarget.nameID);
+            cmd.SetRenderTarget(sourceColorTarget, RenderBufferLoadAction.Load, RenderBufferStoreAction.Store);
+
+            context.ExecuteCommandBuffer(cmd);
+            cmd.Clear();
+
+            var drawingSettings = CreateDrawingSettings(shaderTagId, ref renderingData, SortingCriteria.CommonTransparent);
+            context.DrawRenderers(renderingData.cullResults, ref drawingSettings, ref filteringSettings);
+
+            CommandBufferPool.Release(cmd);
+        }
+
+        public void Dispose()
+        {
+            tempColorTarget?.Release();
+        }
+    }
+}