Alex Technical Art

Unity Built-in转URP速查表

发表于 分类于 Disqus：

本篇文章转自Teofilo Dutra编写的《From Built-in to URP》，其中有很多在写URP管线Shader时需要用到的函数，作为备忘速查表非常实用，所以记录于此。本文经过精简和翻译，不一定适用于大家，可以点击上方链接跳转至作者原文。本文是基于7.3版本的URP编写的，有些暂时还不支持的内容可能在后续版本更新迭代。

结构

首先要在SubShader的Tags中添加”RenderPipeline” = “UniversalPipeline”，并且使用HLSL的宏代替旧版的CG语言宏。

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

Include文件的改动

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 无

其他常用的include文件:

  • Packages/com.unity.render-pipelines.core/ShaderLibrary/SpaceTransforms.hlsl
  • Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderVariablesFunctions.hlsl
  • Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl
  • Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl
  • Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl
  • Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl
  • Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareOpaqueTextue.hlsl

光照模式

Built-in URP
ForwardBase UniversalForward
ForwardAdd 无
Deferred and related UniversalGBuffer seems to have just been added to URP
Vertex and related 无
ShadowCaster ShadowCaster
MotionVectors 暂不支持

URP其他支持的光照模式：

  • DepthOnly
  • Meta (用于烘焙光照贴图)
  • Universal2D

变体(Variants)

URP支持着色器的变体，可以使用#pragma multi_compile宏实现编译不同需求下的着色器，常见的内置关键字有：

  • _MAIN_LIGHT_SHADOWS
  • _MAIN_LIGHT_SHADOWS_CASCADE
  • _ADDITIONAL_LIGHTS_VERTEX
  • _ADDITIONAL_LIGHTS
  • _ADDITIONAL_LIGHT_SHADOWS
  • _SHADOWS_SOFT
  • _MIXED_LIGHTING_SUBTRACTIVE

预定义的着色器预处理宏

辅助宏(Helpers)

Built-in URP
UNITY_PROJ_COORD(a) 无，使用 a.xy/a.w 来代替
UNITY_INITIALIZE_OUTPUT(type, name) ZERO_INITIALIZE(type, name)

阴影贴图

需要包含 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)

纹理/采样器的声明宏

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)

内置的着色器辅助函数

可以在 Packages/com.unity.render-pipelines.core/ShaderLibrary/SpaceTransforms.hlsl 看到下方的所有函数

顶点变换函数

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

泛用的辅助函数

Built-in URP Include
float3 WorldSpaceViewDir (float4 v) float3 GetWorldSpaceViewDir(float3 positionWS) Include “Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderVariablesFunctions.hlsl”
float3 ObjSpaceViewDir (float4 v) 无，使用 TransformWorldToObject(GetCameraPositionWS()) - objectSpacePosition;
float2 ParallaxOffset (half h, half height, half3 viewDir) 可能没有，从 UnityCG.cginc 复制
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” URP中decodeInstructions 为 half4(LIGHTMAP_HDR_MULTIPLIER, LIGHTMAP_HDR_EXPONENT, 0.0h, 0.0h)
float4 EncodeFloatRGBA (float v) 可能没有， 从 UnityCG.cginc 复制
float DecodeFloatRGBA (float4 enc) 可能没有， 从 UnityCG.cginc 复制
float2 EncodeFloatRG (float v) 可能没有， 从 UnityCG.cginc 复制
float DecodeFloatRG (float2 enc) 可能没有， 从 UnityCG.cginc 复制
float2 EncodeViewNormalStereo (float3 n) 可能没有， 从 UnityCG.cginc 复制
float3 DecodeViewNormalStereo (float4 enc4) 可能没有， 从 UnityCG.cginc 复制

前向渲染辅助函数

Built-in URP Include
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，可尝试用half3 VertexLighting(float3 positionWS, half3 normalWS) include “Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”

屏幕空间辅助函数

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

顶点光照的辅助函数

Built-in URP Include
float3 ShadeVertexLights (float4 vertex, float3 normal) 无，可尝试用 UNITY_LIGHTMODEL_AMBIENT.xyz + VertexLighting(…) include “Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”

可以在 Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl 中找到一些通用函数

内置的着色器变量

Built-in URP Include
_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 可能还不支持
unity_4LightPosX0, unity_4LightPosY0, unity_4LightPosZ0 URP中，额外的灯光存储在一个数组或缓冲中(取决于平台),使用Light GetAdditionalLight(uint i, float3 positionWS)获取光照信息 Include “Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_4LightAtten0 URP中，额外的灯光存储在一个数组或缓冲中(取决于平台),使用Light GetAdditionalLight(uint i, float3 positionWS)获取光照信息 Include “Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl”
unity_LightColor URP中，额外的灯光存储在一个数组或缓冲中(取决于平台),使用Light GetAdditionalLight(uint i, float3 positionWS)获取光照信息 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”

可以使用GetAdditionalLight(…)获取额外的光源，也可以使用GetAdditionalLightsCount()查询额外的光源数量。

其他方法

阴影

更多阴影相关函数可以查看 Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl

Built-in URP
UNITY_SHADOW_COORDS(x) 可能没有，可以写作float4 shadowCoord : TEXCOORD0;
TRANSFER_SHADOW(a) a.shadowCoord = TransformWorldToShadowCoord(worldSpacePosition)
SHADOWS_SCREEN 暂不支持

雾

更多雾相关的函数可以查看 Packages/com.unity.render-pipelines.universal/ShaderLibrary/ShaderVariablesFunctions.hlsl

Built-in URP
UNITY_FOG_COORDS(x) 可能没有，可以写作float fogCoord : TEXCOORD0;
UNITY_TRANSFER_FOG(o, outpos) o.fogCoord = ComputeFogFactor(clipSpacePosition.z);
UNITY_APPLY_FOG(coord, col) color = MixFog(color, i.fogCoord);

深度

可以包含 “Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl” 并使用 _CameraDepthTexture来调用深度纹理。也可以使用SampleSceneDepth(…) 和 LoadSceneDepth(…)。

Built-in URP Include
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”

其他

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

后期/特效

URP不支持OnPreCull, OnPreRender, OnPostRender 和 OnRenderImage. 支持 OnRenderObject 和 OnWillRenderObject。RenderPipelineManager提供了渲染管线中注入的位置：

  • beginCameraRendering(ScriptableRenderContext context, Camera camera)
  • endCameraRendering(ScriptableRenderContext context, Camera camera)
  • beginFrameRendering(ScriptableRenderContext context,Camera[] cameras)
  • endFrameRendering(ScriptableRenderContext context,Camera[] cameras)

例如：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
void OnEnable()
{
	RenderPipelineManager.beginCameraRendering += MyCameraRendering;
}

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

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

另外，可以创建ScriptableRendererFeature来实现后期处理效果。可以在管线的不同阶段注入ScriptableRenderPasses：

  • BeforeRendering
  • BeforeRenderingShadows
  • AfterRenderingShadows
  • BeforeRenderingPrepasses
  • AfterRenderingPrePasses
  • BeforeRenderingOpaques
  • AfterRenderingOpaques
  • BeforeRenderingSkybox
  • AfterRenderingSkybox
  • BeforeRenderingTransparents
  • AfterRenderingTransparents
  • BeforeRenderingPostProcessing
  • AfterRenderingPostProcessing
  • AfterRendering

下面是一个示例：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
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);
    }
}

总要恰饭的嘛