【從UnityURP開始探索游戲渲染】專欄-直達

自定義渲染通道是一種改變通用渲染管道（URP）如何渲染場景或場景中的對象的方法。自定義呈現通道(RenderPass)包含自己的Render代碼，可以在注入點將其添加到RenderPass中。

添加自定義呈現通道(RenderPass)：

• 使用Scriptable render pass?API創建自定義render pass的代碼。
• 將自定的render pass注入到URP管線中的指定注入點中，有兩種方式：
  • 用RenderPipelineManager?API注入自定義渲染通道
  • 或者通過創建一個可腳本化的RendererFeature添加到URP渲染器中。

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使用Scriptable render pass?API創建自定義render pass

• Example custom render pass

  using UnityEngine;
  using UnityEngine.Rendering;
  using UnityEngine.Rendering.Universal;internal class ColorBlitPass : ScriptableRenderPass
  {ProfilingSampler m_ProfilingSampler = new ProfilingSampler("ColorBlit");Material m_Material;RTHandle m_CameraColorTarget;float m_Intensity;public ColorBlitPass(Material material){m_Material = material;renderPassEvent = RenderPassEvent.BeforeRenderingPostProcessing;}public void SetTarget(RTHandle colorHandle, float intensity){m_CameraColorTarget = colorHandle;m_Intensity = intensity;}public override void OnCameraSetup(CommandBuffer cmd, ref RenderingData renderingData){ConfigureTarget(m_CameraColorTarget);}public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData){var cameraData = renderingData.cameraData;if (cameraData.camera.cameraType != CameraType.Game)return;if (m_Material == null)return;CommandBuffer cmd = CommandBufferPool.Get();using (new ProfilingScope(cmd, m_ProfilingSampler)){m_Material.SetFloat("_Intensity", m_Intensity);Blitter.BlitCameraTexture(cmd, m_CameraColorTarget, m_CameraColorTarget, m_Material, 0);}context.ExecuteCommandBuffer(cmd);cmd.Clear();CommandBufferPool.Release(cmd);}
  }

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將自定的render pass注入到URP管線中的指定注入點中

用RenderPipelineManager?API注入自定義渲染通道

• 通過RenderPipelineManager的注入點委托提供執行時機，加上Camera的EnqueuePass方法注入自定義RenderPass。

  public class EnqueuePass : MonoBehaviour
  {[SerializeField] private BlurSettings settings;    private BlurRenderPass blurRenderPass;private void OnEnable(){...blurRenderPass = new BlurRenderPass(settings);// Subscribe the OnBeginCamera method to the beginCameraRendering event.RenderPipelineManager.beginCameraRendering += OnBeginCamera;}private void OnDisable(){RenderPipelineManager.beginCameraRendering -= OnBeginCamera;blurRenderPass.Dispose();...}private void OnBeginCamera(ScriptableRenderContext context, Camera cam){...// Use the EnqueuePass method to inject a custom render passcam.GetUniversalAdditionalCameraData().scriptableRenderer.EnqueuePass(blurRenderPass);}
  }

創建一個可腳本化的RendererFeature

此示例執行將屏幕染成綠色的全屏blit。

• 要創建自定義渲染通道，創建一個名為ColorBlitPass.cs的新c#腳本，然后從示例自定義渲染通道部分粘貼代碼。

  • 注意：這個例子使用了Blitter API。不要使用CommandBuffer。URP中的Blit API。更多信息請參考Blit。
  • 使用上面定義好的定制Render Pass

• 要創建Scriptable RendererFeature，將自定義渲染通道添加到渲染循環中，請創建一個名為ColorBlitRendererFeature.cs的新c#腳本，然后將示例Scriptable RendererFeature部分中的代碼粘貼進來。

  • Example Scriptable Renderer Feature Scriptable Renderer Feature 添加 render pass 到渲染循環.

    using UnityEngine;
    using UnityEngine.Rendering;
    using UnityEngine.Rendering.Universal;internal class ColorBlitRendererFeature : ScriptableRendererFeature
    {public Shader m_Shader;public float m_Intensity;Material m_Material;ColorBlitPass m_RenderPass = null;public override void AddRenderPasses(ScriptableRenderer renderer,ref RenderingData renderingData){if (renderingData.cameraData.cameraType == CameraType.Game)renderer.EnqueuePass(m_RenderPass);}public override void SetupRenderPasses(ScriptableRenderer renderer,in RenderingData renderingData){if (renderingData.cameraData.cameraType == CameraType.Game){// Calling ConfigureInput with the ScriptableRenderPassInput.Color argument// ensures that the opaque texture is available to the Render Pass.m_RenderPass.ConfigureInput(ScriptableRenderPassInput.Color);m_RenderPass.SetTarget(renderer.cameraColorTargetHandle, m_Intensity);}}public override void Create(){m_Material = CoreUtils.CreateEngineMaterial(m_Shader);m_RenderPass = new ColorBlitPass(m_Material);}protected override void Dispose(bool disposing){CoreUtils.Destroy(m_Material);}
    }

• 要創建將像素染成綠色的著色器代碼，請創建一個著色器文件，然后從示例著色器部分粘貼代碼。

• Example shader

  • 著色器執行渲染的GPU端。它從相機中采樣顏色紋理，然后輸出綠色值設置為所選強度的顏色。
    注意：與Blitter API一起使用的著色器必須是手工編碼的著色器。圖形著色器與Blitter API不兼容。

    Shader "ColorBlit"
    {SubShader{Tags { "RenderType"="Opaque" "RenderPipeline" = "UniversalPipeline"}LOD 100ZWrite Off Cull OffPass{Name "ColorBlitPass"HLSLPROGRAM#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"// The Blit.hlsl file provides the vertex shader (Vert),// the input structure (Attributes) and the output structure (Varyings)#include "Packages/com.unity.render-pipelines.core/Runtime/Utilities/Blit.hlsl"#pragma vertex Vert#pragma fragment frag// Set the color texture from the camera as the input textureTEXTURE2D_X(_CameraOpaqueTexture);SAMPLER(sampler_CameraOpaqueTexture);// Set up an intensity parameterfloat _Intensity;half4 frag (Varyings input) : SV_Target{UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);// Sample the color from the input texturefloat4 color = SAMPLE_TEXTURE2D_X(_CameraOpaqueTexture, sampler_CameraOpaqueTexture, input.texcoord);// Output the color from the texture, with the green value set to the chosen intensityreturn color * float4(0, _Intensity, 0, 1);}ENDHLSL}}
    }
    

• 將ColorBlitRendererFeature添加到當前URP Renderer資源中。有關更多信息，請參閱向URP渲染器添加渲染器功能。

• 要更改亮度，請調整Color Blit Renderer Feature組件中的Intensity屬性。

注意：如果項目使用XR，為了使示例可視化，在項目中安裝MockHMD XR插件包，然后將渲染模式屬性設置為單通道實例化。

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https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@14.0/manual/renderer-features/custom-rendering-pass-workflow-in-urp.html

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【從UnityURP開始探索游戲渲染】專欄-直達
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