Unity 的可编程渲染管线(Scriptable Render Pipeline) 代表了Unity处理图形方式的一大进步，为用户提供了更多定制管线的能力，我已经开始使用通用管线 (Universal Render Pipeline) 但仍然缺文档，你可以找到包含每个可用函数的信息，但仍然难找到重Built-in 到 URP 的示例。

本文提供重 Built-in 到 URP 的示例总结，希望可以帮助到大家

1.开始之前这里有一些链接可以帮助你深入了解URP

Unity URP 官方文档

UnityURP Github

官方示例工程

Unlit template

Boat attack demo project

Phil Lira’s shader examples

Outline post-effect using ScriptableRendererFeature

1.总体结构

首先添加 "RenderPipeline" = "UniversalPipeline" 到Tag 下一步所有的URP shader 都是使用HLSLPROGRAM/ENDHLSL/etc. 包含的HLSL 编写

Built-in	URP
CGPROGRAM HLSLPROGRAM	HLSLPROGRAM
ENDCG ENDHLSL	ENDHLSL
CGINCLUDE HLSLINCLUDE	HLSLINCLUDE

2.Shader Include 头文件

Content	Built-in	URP
Core	Unity.cginc	Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl
Light	AutoLight.cginc	Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl
Shadows	AutoLight.cginc	Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl
Surface shaders	Lighting.cginc	没有 ,但这个链接可以找到一个辅助项目?here

其他有用的包括

3.灯光模式

Built-in	URP
ForwardBase	UniversalForward
ForwardAdd	无
Deferred and related	UniversalGBuffer 刚被添加URP
Vertex and related	无
ShadowCaster	ShadowCaster
MotionVectors	暂不支持

支持的其他照明模式包括

? ? 1.DepthOnly?

? ? 2. Meta (用于烘焙光照贴图)?

? ? 3.Universal2D

4.变种Variants?

URP 支持变体，你可能需要某些功能 ?#pragma multi_compile ?添加以下关键字

_MAIN_LIGHT_SHADOWS?

_MAIN_LIGHT_SHADOWS_CASCADE?

_ADDITIONAL_LIGHTS_VERTEX?

_ADDITIONAL_LIGHTS?

_ADDITIONAL_LIGHT_SHADOWS?

_SHADOWS_SOFT?

_MIXED_LIGHTING_SUBTRACTIVE

5.预处理宏 Predefined Shader Preprocessor Macros

5.1辅助函数

Built-in	URP
UNITY_PROJ_COORD(a)	Gone. Do?a.xy/a.w?instead
UNITY_INITIALIZE_OUTPUT(type,?name)	ZERO_INITIALIZE(type,?name)

5.2阴影贴图

你必须包含?#include?"Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"

Built-in	URP
UNITY_DECLARE_SHADOWMAP(tex)	TEXTURE2D_SHADOW_PARAM(textureName,?samplerName)
UNITY_SAMPLE_SHADOW(tex,?uv)	SAMPLE_TEXTURE2D_SHADOW(textureName,?samplerName,?coord3)
UNITY_SAMPLE_SHADOW_PROJ(tex,?uv)	SAMPLE_TEXTURE2D_SHADOW(textureName,?samplerName,?coord4.xyz/coord4.w)

5.3贴图/采样器声明宏

Unity 有很多纹理/采样器用来兼容不同平台，这些仍然处理URP 中，但现在有了不同的名称和

新添加的，由于数量很多这里不会全部列出，你可以针对不同API平台查看他们的具体定义?API includes.

Built-in	URP
UNITY_DECLARE_TEX2D(name)	TEXTURE2D(textureName);?SAMPLER(samplerName);
UNITY_DECLARE_TEX2D_NOSAMPLER(name)	TEXTURE2D(textureName);
UNITY_DECLARE_TEX2DARRAY(name)	TEXTURE2D_ARRAY(textureName);?SAMPLER(samplerName);
UNITY_SAMPLE_TEX2D(name,?uv)	SAMPLE_TEXTURE2D(textureName,?samplerName,?coord2)
UNITY_SAMPLE_TEX2D_SAMPLER(name,?samplername,?uv)	SAMPLE_TEXTURE2D(textureName,?samplerName,?coord2)
UNITY_SAMPLE_TEX2DARRAY(name,?uv)	SAMPLE_TEXTURE2D_ARRAY(textureName,?samplerName,?coord2,?index)
UNITY_SAMPLE_TEX2DARRAY_LOD(name,?uv,?lod)	SAMPLE_TEXTURE2D_ARRAY_LOD(textureName,?samplerName,?coord2,?index,?lod)

需要注意的一点是 SCREENSPACE_TEXTURE 已经变为 TEXTURE2D_X ，如果你正在做一些VR (单通道/立体渲染)下的屏幕空间的特效

你必须用TEXTURE2D_X?声明 ,此宏将正确的处理纹理(是否为数组)，还必须使用 SAMPLE_TEXTURE2D_X 采样贴图，UV 使用

UnityStereoTransformScreenSpaceTex

6.内置的shader 辅助函数

你需要包含

?#include?"Packages/com.unity.render-pipelines.core/ShaderLibrary/SpaceTransforms.hlsl"

6.1顶点变换函数

Built-in	URP
float4?UnityObjectToClipPos(float3 pos)	float4?TransformObjectToHClip(float3 positionOS)
float3?UnityObjectToViewPos(float3 pos)	TransformWorldToView(TransformObjectToWorld(positionOS))

6.2通用辅助函数

Built-in	URP	?
float3?WorldSpaceViewDir?(float4 v)	float3?GetWorldSpaceViewDir(float3 positionWS)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderVariablesFunctions.hlsl”
float3?ObjSpaceViewDir?(float4 v)	Gone. Do?TransformWorldToObject(GetCameraPositionWS()) -?objectSpacePosition;
float2?ParallaxOffset?(half h,?half height,?half3 viewDir)	无? 重 UnityCG.cginc拷贝
fixed?Luminance?(fixed3 c)	real?Luminance(real3 linearRgb)	Include?“Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl”
fixed3?DecodeLightmap?(fixed4 color)	real3?DecodeLightmap(real4 encodedIlluminance,?real4 decodeInstructions)	Include?“Packages/com.unity.render-pipelines.core/ShaderLibrary/EntityLighting.hlsl” decodeInstructions?is used as?half4(LIGHTMAP_HDR_MULTIPLIER, LIGHTMAP_HDR_EXPONENT, 0.0h, 0.0h)?by URP
float4?EncodeFloatRGBA?(float v)	无? 重?UnityCG.cginc 拷贝
float?DecodeFloatRGBA?(float4 enc)	无??重?UnityCG.cginc 拷贝
float2?EncodeFloatRG?(float v)	无??重?UnityCG.cginc 拷贝
float?DecodeFloatRG?(float2 enc)	无??重?UnityCG.cginc 拷贝
float2?EncodeViewNormalStereo?(float3 n)	无??重?UnityCG.cginc 拷贝
float3?DecodeViewNormalStereo?(float4 enc4)	无??重?UnityCG.cginc 拷贝

6.3前向渲染辅助函数

Built-in	URP
float3?WorldSpaceLightDir?(float4 v)	_MainLightPosition.xyz?-?TransformObjectToWorld(objectSpacePosition)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl”
float3?ObjSpaceLightDir?(float4 v)	TransformWorldToObject(_MainLightPosition.xyz) -?objectSpacePosition	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl”
float3?Shade4PointLights?(…)	无. 你可以尝试这个?half3 VertexLighting(float3 positionWS, half3 normalWS)	For?VertexLighting(...)?include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”

6.4屏幕空间辅助函数

Built-in	URP	?
float4?ComputeScreenPos?(float4 clipPos)	float4?ComputeScreenPos(float4 positionCS)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderVariablesFunctions.hlsl”
float4?ComputeGrabScreenPos?(float4 clipPos)	无.

6.5顶点光照辅助函数

Built-in	URP	?
float3?ShadeVertexLights?(float4 vertex,?float3 normal)	无.你可以尝试这个??UNITY_LIGHTMODEL_AMBIENT.xyz + VertexLighting(...)	For?VertexLighting(...)?include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”

公用的函数可以在这里找到?

7.内置shader 变体

“Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl”.

除了灯光大多数的shader 变量保持不变

7.1灯光

Built-in	URP	?
_LightColor0	_MainLightColor	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl”
_WorldSpaceLightPos0	_MainLightPosition	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl”
_LightMatrix0	无? 尚未支持烘焙
unity_4LightPosX0, ?unity_4LightPosY0, ?unity_4LightPosZ0	在URP 中,其他的光源储存在数组 Array/缓冲区Buffer 中(取决于平台). ? ? ?检索灯光信息?? Light GetAdditionalLight(uint i, float3 positionWS)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_4LightAtten0	在URP 中,其他的光源储存在数组 Array/缓冲区Buffer 中(取决于平台). ? ? ?检索灯光信息? Light GetAdditionalLight(uint i, float3 positionWS)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_LightColor	在URP 中,其他的光源储存在数组 Array/缓冲区Buffer 中(取决于平台). ? ? ?检索灯光信息? Light GetAdditionalLight(uint i, float3 positionWS)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_WorldToShadow	float4x4 _MainLightWorldToShadow[MAX_SHADOW_CASCADES + 1]?or?_AdditionalLightsWorldToShadow[MAX_VISIBLE_LIGHTS]	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl”

如果你要使用 ?GetAdditionalLight(...) 遍历灯光，你可以使用它来查询其他灯光数量 GetAdditionalLightsCount()

8.杂项
8.1shadow?

Built-in	URP	?
UNITY_SHADOW_COORDS(x)	无? 自定义一个.?float4 shadowCoord : TEXCOORD0;
TRANSFER_SHADOW(a)	a.shadowCoord?=?TransformWorldToShadowCoord(worldSpacePosition)	当启用级联时(CSM ) 在片段着色器应用防止伪影
SHADOWS_SCREEN	无. 不支持.

8.2雾Fog

8.3深度Depth

要使用相机深度请包含??“Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl”

你还需要声明 _CameraDepthTexture 及帮助函数 ?SampleSceneDepth(...) 和LoadSceneDepth(...).

Built-in	URP	?
LinearEyeDepth(sceneZ)	LinearEyeDepth(sceneZ,?_ZBufferParams)	Include?“Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl”
Linear01Depth(sceneZ)	Linear01Depth(sceneZ,?_ZBufferParams)	Include?“Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl”

8.4其他

Built-in	URP	?
ShadeSH9(normal)	SampleSH(normal)	Include?“Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_ColorSpaceLuminance	无. 请使用?Luminance()	Include?“Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl”

9.后处理/VFX (视觉特效)

URP不支持OnPreCull，OnPreRender，OnPostRender和OnRenderImage，

它确实支持OnRenderObject和OnWillRenderObject，但是您可能会发现问题，具体取决于你想做什么

RenderPipelineManager 提供以下注入点

beginCameraRendering(ScriptableRenderContext context, Camera camera)

endCameraRendering(ScriptableRenderContext context, Camera camera)

beginFrameRendering(ScriptableRenderContext context,Camera[] cameras)

endFrameRendering(ScriptableRenderContext context,Camera[] cameras)

用法示例

void OnEnable()
{
????????? RenderPipelineManager.beginCameraRendering += MyCameraRendering;
}

void OnDisable()
{
????????? RenderPipelineManager.beginCameraRendering -= MyCameraRendering;
}

void MyCameraRendering(ScriptableRenderContext context, Camera camera)
{
????????? ...
????????? if(camera == myEffectCamera)
????????? {
????????? ...
????????? }
????????? ...
}

虽然支持OnWillRenderObject，但是，如果您需要在其中执行渲染调用（例如，水反射/折射），它就无法正常工作。
?

在这种情况下，用begin / endCameraRendering（如上面的示例）替换OnWillRenderObject，然后从URP而不是Camera.Render（）中调用RenderSingleCamera（）。更改上面的示例

void MyCameraRendering(ScriptableRenderContext context, Camera camera)
{
????????? ...
????????? if(camera == myEffectCamera)
????????? {
????????? ...
??????????????????? UniversalRenderPipeline.RenderSingleCamera(context, camera);
????????? }
????????? ...
}

使用后处理的另一种方法是使用ScriptableRendererFeature。这篇文章很好地解释了使用此功能的描边效果。

A ScriptableRendererFeature允许您ScriptableRenderPass(es)在管道的不同阶段进行注入，

BeforeRendering

BeforeRenderingShadows

AfterRenderingShadows

BeforeRenderingPrepasses

AfterRenderingPrePasses

BeforeRenderingOpaques

AfterRenderingOpaques

BeforeRenderingSkybox

AfterRenderingSkybox

BeforeRenderingTransparents

AfterRenderingTransparents

BeforeRenderingPostProcessing

AfterRenderingPostProcessing

AfterRendering

这是使用 ScriptableRendererFeature 自定义材质执行blit?的简单示例：

public class CustomRenderPassFeature : ScriptableRendererFeature
{
??? class CustomRenderPass : ScriptableRenderPass
??? {
??????? CustomRPSettings _CustomRPSettings;
??????? RenderTargetHandle _TemporaryColorTexture;

??????? private RenderTargetIdentifier _Source;
??????? private RenderTargetHandle _Destination;

??????? public CustomRenderPass(CustomRPSettings settings)
??????? {
??????????? _CustomRPSettings = settings;
??????? }

??????? public void Setup(RenderTargetIdentifier source, RenderTargetHandle destination)
??????? {
??????????? _Source = source;
??????????? _Destination = destination;
??????? }

??????? public override void Configure(CommandBuffer cmd, RenderTextureDescriptor cameraTextureDescriptor)
??????? {
??????????? _TemporaryColorTexture.Init("_TemporaryColorTexture");
??????? }

??????? public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
??????? {
??????????? CommandBuffer cmd = CommandBufferPool.Get("My Pass");

??????????? if (_Destination == RenderTargetHandle.CameraTarget)
??????????? {
??????????????? cmd.GetTemporaryRT(_TemporaryColorTexture.id, renderingData.cameraData.cameraTargetDescriptor, FilterMode.Point);

??????????????? cmd.Blit(_Source, _TemporaryColorTexture.Identifier());

??????????????? cmd.Blit(_TemporaryColorTexture.Identifier(), _Source, _CustomRPSettings.m_Material);
??????????? }
??????????? else
??????????? {
??????????????? cmd.Blit(_Source, _Destination.Identifier(), _CustomRPSettings.m_Material, 0);
??????????? }

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

??????? public override void FrameCleanup(CommandBuffer cmd)
??????? {
??????????? if (_Destination == RenderTargetHandle.CameraTarget)
??????????? {
??????????????? cmd.ReleaseTemporaryRT(_TemporaryColorTexture.id);
??????????? }
??????? }
??? }

??? [System.Serializable]
??? public class CustomRPSettings
??? {
??????? public Material m_Material;
??? }

??? public CustomRPSettings m_CustomRPSettings = new CustomRPSettings();
??? CustomRenderPass _ScriptablePass;
??? public override void Create()
??? {
??????? _ScriptablePass = new CustomRenderPass(m_CustomRPSettings);
??????? _ScriptablePass.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;
??? }

??? public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
??? {
??????? _ScriptablePass.Setup(renderer.cameraColorTarget, RenderTargetHandle.CameraTarget);
??????? renderer.EnqueuePass(_ScriptablePass);
??? }
}

点击??“Create > Rendering > Universal Render Pipeline > Renderer Feature”.??你可以创建一个 ScriptableRendererFeature ?

你创建的功能必须添加到 ForwardRenderer，选择?ForwardRenderer 点击?Add Renderer Feature 并选择你要添加的功能，

例如如果你使用了上面的示例代码，可以看到一个可用的材质槽