【URP】Unity3D物体遮罩的多种方案实现

SmalBox2025-09-05 11:41

【从UnityURP开始探索游戏渲染】专栏-直达

物体自身遮罩控制方案

基于Unity URP实现3D物体方向性动态遮罩

‌Shader核心功能‌：

  • 通过_MaskDirection向量定义遮罩方向
  • 使用_MaskProgress参数(0-1范围)控制显示比例
  • 基于顶点世界坐标在遮罩方向上的投影值进行裁剪(clip)
  • 兼容URP渲染管线标准结构

‌控制器特点‌：

  • 支持运行时动态调整遮罩方向和进度

  • 内置演示动画(旋转方向和进度波动)

  • 提供外部调用接口用于程序控制

  • 自动规范化方向向量确保计算准确

  • DirectionalMask.shader

    c 复制代码 
    Shader "Custom/DirectionalMask"
{
    Properties
    {
        _MainTex("Texture", 2D) = "white" {}
        _MaskDirection("Mask Direction", Vector) = (1,0,0,0)
        _MaskProgress("Mask Progress", Range(0, 1)) = 0.5
    }

    SubShader
    {
        Tags { "RenderType"="Opaque" "RenderPipeline"="UniversalPipeline" }

        HLSLINCLUDE
        #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

        struct Attributes
        {
            float4 positionOS : POSITION;
            float2 uv : TEXCOORD0;
        };

        struct Varyings
        {
            float4 positionCS : SV_POSITION;
            float2 uv : TEXCOORD0;
            float3 positionWS : TEXCOORD1;
        };

        TEXTURE2D(_MainTex);
        SAMPLER(sampler_MainTex);
        float4 _MainTex_ST;
        float3 _MaskDirection;
        float _MaskProgress;

        Varyings Vert(Attributes input)
        {
            Varyings output;
            output.positionCS = TransformObjectToHClip(input.positionOS.xyz);
            output.uv = TRANSFORM_TEX(input.uv, _MainTex);
            output.positionWS = TransformObjectToWorld(input.positionOS.xyz);
            return output;
        }

        half4 Frag(Varyings input) : SV_Target
        {
            half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, input.uv);
            
            // 计算物体顶点在遮罩方向上的投影比例
            float dotProduct = dot(normalize(input.positionWS), normalize(_MaskDirection));
            float normalizedDot = (dotProduct + 1) * 0.5; // 映射到0-1范围
            
            // 根据进度参数裁剪
            clip(normalizedDot - _MaskProgress);
            
            return col;
        }
        ENDHLSL

        Pass
        {
            HLSLPROGRAM
            #pragma vertex Vert
            #pragma fragment Frag
            ENDHLSL
        }
    }
}

  • DirectionalMaskController.cs

    csharp 复制代码 
    using UnityEngine;

public class DirectionalMaskController : MonoBehaviour
{
    [SerializeField] private Renderer _targetRenderer;
    [SerializeField] private Vector3 _maskDirection = Vector3.right;
    [Range(0, 1)] public float maskProgress = 0.5f;
    [SerializeField] private float _rotationSpeed = 30f;
    [SerializeField] private float _progressSpeed = 0.2f;

    private Material _material;
    private static readonly int MaskDirection = Shader.PropertyToID("_MaskDirection");
    private static readonly int MaskProgress = Shader.PropertyToID("_MaskProgress");

    void Start()
    {
        _material = _targetRenderer.material;
        UpdateShaderParams();
    }

    void Update()
    {
        // 动态旋转遮罩方向
        _maskDirection = Quaternion.Euler(0, _rotationSpeed * Time.deltaTime, 0) * _maskDirection;
        
        // 动态调整遮罩进度
        maskProgress = Mathf.PingPong(Time.time * _progressSpeed, 1f);
        
        UpdateShaderParams();
    }

    private void UpdateShaderParams()
    {
        _material.SetVector(MaskDirection, _maskDirection.normalized);
        _material.SetFloat(MaskProgress, maskProgress);
    }

    // 外部调用接口
    public void SetMaskDirection(Vector3 newDirection)
    {
        _maskDirection = newDirection.normalized;
        UpdateShaderParams();
    }

    public void SetMaskProgress(float progress)
    {
        maskProgress = Mathf.Clamp01(progress);
        UpdateShaderParams();
    }
}

‌扩展：

  • 可添加_MaskSharpness参数控制边缘过渡柔和度
  • 结合Stencil Buffer实现多物体遮罩叠加
  • 通过AnimationCurve控制进度变化曲线

该方案相比基础遮罩实现增加了方向向量参数和动态进度控制，通过顶点投影计算实现方向性裁剪效果。控制器脚本支持运行时动态调整所有参数，并保持与Shader的高效数据交互。

‌HLSL Shader实现‌（基于透明度遮罩）：

  • unity_urp遮罩shader

    c 复制代码 
    Shader "Custom/TransparentColorURP" {
    Properties {
        _Color("Color Tint", Color) = (1,1,1,1)
        _MainTex("Main Tex", 2D) = "white" {}
        _AlphaScale("Alpha Scale", Range(0, 1)) = 0.5
    }
    SubShader {
        Pass {
            ZWrite On
            ColorMask 0
        }
        Pass {
            ZWrite Off
            Blend SrcAlpha OneMinusSrcAlpha
            // HLSL代码...
        }
    }
}

‌控制脚本‌：

  • unity_遮罩控制脚本

    csharp 复制代码 
    public class MaskController : MonoBehaviour {
    public Renderer targetRenderer;
    public float maskProgress = 0.5f;

    void Update() {
        targetRenderer.material.SetFloat("_AlphaScale", 
            Mathf.PingPong(Time.time, 1f));
    }
}

模板测试实现方案

‌模板Shader核心代码‌：

  • 创建一个四边形，将StencilMask做成材质赋给它。通过调整四边形的大小，来调整遮罩区域。

  • 当然也可在c#端动态调整mesh的点来做动态异形遮罩。

  • 将需要被遮罩的URP中Lit的物体，换成StencilLit的shader。这样原来的Lit的物体就支持StencilMask的遮罩了。

  • StencilMask.shader

    c 复制代码 
    Shader "Custom/StencilMask"
{
    SubShader
    {
        Tags { "RenderType"="Opaque" "Queue"="Geometry-100" }
        
        Pass
        {
            ColorMask 0
            ZWrite Off
            
            Stencil {
                Ref 1
                Comp Always
                Pass Replace
            }
        }
    }
}

  • StencilLit.shader

    c 复制代码 
    Shader "Universal Render Pipeline/StencilLit"
{
    Properties
    {
        // Specular vs Metallic workflow
        _WorkflowMode("WorkflowMode", Float) = 1.0

        [MainTexture] _BaseMap("Albedo", 2D) = "white" {}
        [MainColor] _BaseColor("Color", Color) = (1,1,1,1)

        _Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5

        _Smoothness("Smoothness", Range(0.0, 1.0)) = 0.5
        _SmoothnessTextureChannel("Smoothness texture channel", Float) = 0

        _Metallic("Metallic", Range(0.0, 1.0)) = 0.0
        _MetallicGlossMap("Metallic", 2D) = "white" {}

        _SpecColor("Specular", Color) = (0.2, 0.2, 0.2)
        _SpecGlossMap("Specular", 2D) = "white" {}

        [ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
        [ToggleOff] _EnvironmentReflections("Environment Reflections", Float) = 1.0

        _BumpScale("Scale", Float) = 1.0
        _BumpMap("Normal Map", 2D) = "bump" {}

        _Parallax("Scale", Range(0.005, 0.08)) = 0.005
        _ParallaxMap("Height Map", 2D) = "black" {}

        _OcclusionStrength("Strength", Range(0.0, 1.0)) = 1.0
        _OcclusionMap("Occlusion", 2D) = "white" {}

        [HDR] _EmissionColor("Color", Color) = (0,0,0)
        _EmissionMap("Emission", 2D) = "white" {}

        _DetailMask("Detail Mask", 2D) = "white" {}
        _DetailAlbedoMapScale("Scale", Range(0.0, 2.0)) = 1.0
        _DetailAlbedoMap("Detail Albedo x2", 2D) = "linearGrey" {}
        _DetailNormalMapScale("Scale", Range(0.0, 2.0)) = 1.0
        [Normal] _DetailNormalMap("Normal Map", 2D) = "bump" {}

        // SRP batching compatibility for Clear Coat (Not used in Lit)
        [HideInInspector] _ClearCoatMask("_ClearCoatMask", Float) = 0.0
        [HideInInspector] _ClearCoatSmoothness("_ClearCoatSmoothness", Float) = 0.0

        // Blending state
        _Surface("__surface", Float) = 0.0
        _Blend("__blend", Float) = 0.0
        _Cull("__cull", Float) = 2.0
        [ToggleUI] _AlphaClip("__clip", Float) = 0.0
        [HideInInspector] _SrcBlend("__src", Float) = 1.0
        [HideInInspector] _DstBlend("__dst", Float) = 0.0
        [HideInInspector] _SrcBlendAlpha("__srcA", Float) = 1.0
        [HideInInspector] _DstBlendAlpha("__dstA", Float) = 0.0
        [HideInInspector] _ZWrite("__zw", Float) = 1.0
        [HideInInspector] _BlendModePreserveSpecular("_BlendModePreserveSpecular", Float) = 1.0
        [HideInInspector] _AlphaToMask("__alphaToMask", Float) = 0.0

        [ToggleUI] _ReceiveShadows("Receive Shadows", Float) = 1.0
        // Editmode props
        _QueueOffset("Queue offset", Float) = 0.0

        // ObsoleteProperties
        [HideInInspector] _MainTex("BaseMap", 2D) = "white" {}
        [HideInInspector] _Color("Base Color", Color) = (1, 1, 1, 1)
        [HideInInspector] _GlossMapScale("Smoothness", Float) = 0.0
        [HideInInspector] _Glossiness("Smoothness", Float) = 0.0
        [HideInInspector] _GlossyReflections("EnvironmentReflections", Float) = 0.0

        [HideInInspector][NoScaleOffset]unity_Lightmaps("unity_Lightmaps", 2DArray) = "" {}
        [HideInInspector][NoScaleOffset]unity_LightmapsInd("unity_LightmapsInd", 2DArray) = "" {}
        [HideInInspector][NoScaleOffset]unity_ShadowMasks("unity_ShadowMasks", 2DArray) = "" {}
    }

    SubShader
    {
        // Universal Pipeline tag is required. If Universal render pipeline is not set in the graphics settings
        // this Subshader will fail. One can add a subshader below or fallback to Standard built-in to make this
        // material work with both Universal Render Pipeline and Builtin Unity Pipeline
        Tags
        {
            "RenderType" = "Opaque"
            "RenderPipeline" = "UniversalPipeline"
            "UniversalMaterialType" = "Lit"
            "IgnoreProjector" = "True"
        }
        LOD 300

        // ------------------------------------------------------------------
        //  Forward pass. Shades all light in a single pass. GI + emission + Fog
        Pass
        {
            // Lightmode matches the ShaderPassName set in UniversalRenderPipeline.cs. SRPDefaultUnlit and passes with
            // no LightMode tag are also rendered by Universal Render Pipeline
            Name "ForwardLit"
            Tags
            {
                "LightMode" = "UniversalForward"
            }

            // -------------------------------------
            // Render State Commands
            Blend[_SrcBlend][_DstBlend], [_SrcBlendAlpha][_DstBlendAlpha]
            ZWrite[_ZWrite]
            Cull[_Cull]
            AlphaToMask[_AlphaToMask]
            Stencil {
                Ref 1
                Comp Equal
                Pass Keep
            }

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex LitPassVertex
            #pragma fragment LitPassFragment

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local _NORMALMAP
            #pragma shader_feature_local _PARALLAXMAP
            #pragma shader_feature_local _RECEIVE_SHADOWS_OFF
            #pragma shader_feature_local _ _DETAIL_MULX2 _DETAIL_SCALED
            #pragma shader_feature_local_fragment _SURFACE_TYPE_TRANSPARENT
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _ _ALPHAPREMULTIPLY_ON _ALPHAMODULATE_ON
            #pragma shader_feature_local_fragment _EMISSION
            #pragma shader_feature_local_fragment _METALLICSPECGLOSSMAP
            #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
            #pragma shader_feature_local_fragment _OCCLUSIONMAP
            #pragma shader_feature_local_fragment _SPECULARHIGHLIGHTS_OFF
            #pragma shader_feature_local_fragment _ENVIRONMENTREFLECTIONS_OFF
            #pragma shader_feature_local_fragment _SPECULAR_SETUP

            // -------------------------------------
            // Universal Pipeline keywords
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
            #pragma multi_compile _ _ADDITIONAL_LIGHTS_VERTEX _ADDITIONAL_LIGHTS
            #pragma multi_compile _ EVALUATE_SH_MIXED EVALUATE_SH_VERTEX
            #pragma multi_compile_fragment _ _ADDITIONAL_LIGHT_SHADOWS
            #pragma multi_compile_fragment _ _REFLECTION_PROBE_BLENDING
            #pragma multi_compile_fragment _ _REFLECTION_PROBE_BOX_PROJECTION
            #pragma multi_compile_fragment _ _SHADOWS_SOFT _SHADOWS_SOFT_LOW _SHADOWS_SOFT_MEDIUM _SHADOWS_SOFT_HIGH
            #pragma multi_compile_fragment _ _SCREEN_SPACE_OCCLUSION
            #pragma multi_compile_fragment _ _DBUFFER_MRT1 _DBUFFER_MRT2 _DBUFFER_MRT3
            #pragma multi_compile_fragment _ _LIGHT_COOKIES
            #pragma multi_compile _ _LIGHT_LAYERS
            #pragma multi_compile _ _FORWARD_PLUS
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/RenderingLayers.hlsl"

            // -------------------------------------
            // Unity defined keywords
            #pragma multi_compile _ LIGHTMAP_SHADOW_MIXING
            #pragma multi_compile _ SHADOWS_SHADOWMASK
            #pragma multi_compile _ DIRLIGHTMAP_COMBINED
            #pragma multi_compile _ LIGHTMAP_ON
            #pragma multi_compile _ DYNAMICLIGHTMAP_ON
            #pragma multi_compile_fragment _ LOD_FADE_CROSSFADE
            #pragma multi_compile_fog
            #pragma multi_compile_fragment _ DEBUG_DISPLAY

            //--------------------------------------
            // GPU Instancing
            #pragma multi_compile_instancing
            #pragma instancing_options renderinglayer
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitForwardPass.hlsl"
            ENDHLSL
        }

        Pass
        {
            Name "ShadowCaster"
            Tags
            {
                "LightMode" = "ShadowCaster"
            }

            // -------------------------------------
            // Render State Commands
            ZWrite On
            ZTest LEqual
            ColorMask 0
            Cull[_Cull]

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex ShadowPassVertex
            #pragma fragment ShadowPassFragment

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A

            //--------------------------------------
            // GPU Instancing
            #pragma multi_compile_instancing
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            // -------------------------------------
            // Universal Pipeline keywords

            // -------------------------------------
            // Unity defined keywords
            #pragma multi_compile_fragment _ LOD_FADE_CROSSFADE

            // This is used during shadow map generation to differentiate between directional and punctual light shadows, as they use different formulas to apply Normal Bias
            #pragma multi_compile_vertex _ _CASTING_PUNCTUAL_LIGHT_SHADOW

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/ShadowCasterPass.hlsl"
            ENDHLSL
        }

        Pass
        {
            // Lightmode matches the ShaderPassName set in UniversalRenderPipeline.cs. SRPDefaultUnlit and passes with
            // no LightMode tag are also rendered by Universal Render Pipeline
            Name "GBuffer"
            Tags
            {
                "LightMode" = "UniversalGBuffer"
            }

            // -------------------------------------
            // Render State Commands
            ZWrite[_ZWrite]
            ZTest LEqual
            Cull[_Cull]

            HLSLPROGRAM
            #pragma target 4.5

            // Deferred Rendering Path does not support the OpenGL-based graphics API:
            // Desktop OpenGL, OpenGL ES 3.0, WebGL 2.0.
            #pragma exclude_renderers gles3 glcore

            // -------------------------------------
            // Shader Stages
            #pragma vertex LitGBufferPassVertex
            #pragma fragment LitGBufferPassFragment

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local _NORMALMAP
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            //#pragma shader_feature_local_fragment _ALPHAPREMULTIPLY_ON
            #pragma shader_feature_local_fragment _EMISSION
            #pragma shader_feature_local_fragment _METALLICSPECGLOSSMAP
            #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
            #pragma shader_feature_local_fragment _OCCLUSIONMAP
            #pragma shader_feature_local _PARALLAXMAP
            #pragma shader_feature_local _ _DETAIL_MULX2 _DETAIL_SCALED

            #pragma shader_feature_local_fragment _SPECULARHIGHLIGHTS_OFF
            #pragma shader_feature_local_fragment _ENVIRONMENTREFLECTIONS_OFF
            #pragma shader_feature_local_fragment _SPECULAR_SETUP
            #pragma shader_feature_local _RECEIVE_SHADOWS_OFF

            // -------------------------------------
            // Universal Pipeline keywords
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS _MAIN_LIGHT_SHADOWS_CASCADE _MAIN_LIGHT_SHADOWS_SCREEN
            //#pragma multi_compile _ _ADDITIONAL_LIGHTS_VERTEX _ADDITIONAL_LIGHTS
            //#pragma multi_compile _ _ADDITIONAL_LIGHT_SHADOWS
            #pragma multi_compile_fragment _ _REFLECTION_PROBE_BLENDING
            #pragma multi_compile_fragment _ _REFLECTION_PROBE_BOX_PROJECTION
            #pragma multi_compile_fragment _ _SHADOWS_SOFT _SHADOWS_SOFT_LOW _SHADOWS_SOFT_MEDIUM _SHADOWS_SOFT_HIGH
            #pragma multi_compile_fragment _ _DBUFFER_MRT1 _DBUFFER_MRT2 _DBUFFER_MRT3
            #pragma multi_compile_fragment _ _RENDER_PASS_ENABLED
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/RenderingLayers.hlsl"

            // -------------------------------------
            // Unity defined keywords
            #pragma multi_compile _ LIGHTMAP_SHADOW_MIXING
            #pragma multi_compile _ SHADOWS_SHADOWMASK
            #pragma multi_compile _ DIRLIGHTMAP_COMBINED
            #pragma multi_compile _ LIGHTMAP_ON
            #pragma multi_compile _ DYNAMICLIGHTMAP_ON
            #pragma multi_compile_fragment _ LOD_FADE_CROSSFADE
            #pragma multi_compile_fragment _ _GBUFFER_NORMALS_OCT

            //--------------------------------------
            // GPU Instancing
            #pragma multi_compile_instancing
            #pragma instancing_options renderinglayer
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitGBufferPass.hlsl"
            ENDHLSL
        }

        Pass
        {
            Name "DepthOnly"
            Tags
            {
                "LightMode" = "DepthOnly"
            }

            // -------------------------------------
            // Render State Commands
            ZWrite On
            ColorMask R
            Cull[_Cull]

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex DepthOnlyVertex
            #pragma fragment DepthOnlyFragment

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A

            // -------------------------------------
            // Unity defined keywords
            #pragma multi_compile_fragment _ LOD_FADE_CROSSFADE

            //--------------------------------------
            // GPU Instancing
            #pragma multi_compile_instancing
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/DepthOnlyPass.hlsl"
            ENDHLSL
        }

        // This pass is used when drawing to a _CameraNormalsTexture texture
        Pass
        {
            Name "DepthNormals"
            Tags
            {
                "LightMode" = "DepthNormals"
            }

            // -------------------------------------
            // Render State Commands
            ZWrite On
            Cull[_Cull]

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex DepthNormalsVertex
            #pragma fragment DepthNormalsFragment

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local _NORMALMAP
            #pragma shader_feature_local _PARALLAXMAP
            #pragma shader_feature_local _ _DETAIL_MULX2 _DETAIL_SCALED
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A

            // -------------------------------------
            // Unity defined keywords
            #pragma multi_compile_fragment _ LOD_FADE_CROSSFADE

            // -------------------------------------
            // Universal Pipeline keywords
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/RenderingLayers.hlsl"

            //--------------------------------------
            // GPU Instancing
            #pragma multi_compile_instancing
            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitDepthNormalsPass.hlsl"
            ENDHLSL
        }

        // This pass it not used during regular rendering, only for lightmap baking.
        Pass
        {
            Name "Meta"
            Tags
            {
                "LightMode" = "Meta"
            }

            // -------------------------------------
            // Render State Commands
            Cull Off

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex UniversalVertexMeta
            #pragma fragment UniversalFragmentMetaLit

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local_fragment _SPECULAR_SETUP
            #pragma shader_feature_local_fragment _EMISSION
            #pragma shader_feature_local_fragment _METALLICSPECGLOSSMAP
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
            #pragma shader_feature_local _ _DETAIL_MULX2 _DETAIL_SCALED
            #pragma shader_feature_local_fragment _SPECGLOSSMAP
            #pragma shader_feature EDITOR_VISUALIZATION

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitMetaPass.hlsl"

            ENDHLSL
        }

        Pass
        {
            Name "Universal2D"
            Tags
            {
                "LightMode" = "Universal2D"
            }

            // -------------------------------------
            // Render State Commands
            Blend[_SrcBlend][_DstBlend]
            ZWrite[_ZWrite]
            Cull[_Cull]

            HLSLPROGRAM
            #pragma target 2.0

            // -------------------------------------
            // Shader Stages
            #pragma vertex vert
            #pragma fragment frag

            // -------------------------------------
            // Material Keywords
            #pragma shader_feature_local_fragment _ALPHATEST_ON
            #pragma shader_feature_local_fragment _ALPHAPREMULTIPLY_ON

            #include_with_pragmas "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DOTS.hlsl"

            // -------------------------------------
            // Includes
            #include "Packages/com.unity.render-pipelines.universal/Shaders/LitInput.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/Shaders/Utils/Universal2D.hlsl"
            ENDHLSL
        }
    }

    FallBack "Hidden/Universal Render Pipeline/FallbackError"
    CustomEditor "UnityEditor.Rendering.Universal.ShaderGUI.LitShader"
}

‌RenderFeature配置要点‌：

  • 需创建URP Renderer Feature
  • 设置Layer Mask匹配目标层级
  • 在后处理前添加Pass

三、其他实现方式

‌多Pass深度测试法‌：

c 复制代码 
Pass {
    ZTest Greater
    ZWrite On
    ColorMask 0
}
Pass {
    ZTest LEqual
    // 正常渲染...
}

‌UGUI Mask混合方案‌：

  • 使用RectTransform确定遮罩区域
  • 通过第二摄像机渲染3D物体
  • 结合UI Mask组件控制显示范围

‌RenderTexture遮罩‌：

  • 创建临时RenderTexture
  • 使用特定Shader渲染遮罩通道
  • 通过后期处理合成最终效果

四、方案对比

方案类型 优点 适用场景
模板测试 高性能，精确控制 角色轮廓/固定形状遮罩
多Pass 无需额外纹理 简单遮挡提示
UGUI混合 可结合UI系统 HUD元素遮罩
RenderTexture 效果最灵活 复杂动态遮罩

模板测试适合需要精确控制像素级显示的场景，而多Pass方案更适合简单的遮挡提示效果

【从UnityURP开始探索游戏渲染】专栏-直达

（欢迎点赞留言探讨，更多人加入进来能更加完善这个探索的过程，🙏）

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