工程截图

Shader

Shader "Custom/SimpleURP_2D"
{
    Properties
    {
        //属性特性参见 ShaderPropertyFlags
        [PerRendererData] [MainTexture] [HideInInspector]
        _MainTex ("Base Texture", 2D) = "white" {}
        _Cutoff ("Cutoff", Range(0, 1)) = 0
    }
    SubShader
    {
        Tags
        {
            "Queue" = "Transparent"
            "RenderType" = "Transparent"
            "RenderPipeline" = "UniversalPipeline"
        }

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

            Blend SrcAlpha OneMinusSrcAlpha
            ZWrite Off
            Cull Off

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma shader_feature _ALPHATEST_ON
            #pragma shader_feature _ALPHAPREMULTIPLY_ON

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

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv         : TEXCOORD0;
                //UGUI将组件的color值传递到这里(例如 Image.color)
                float4 color      : COLOR;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct Varyings
            {
                float2 uv     : TEXCOORD0;
                float4 vertex : SV_POSITION;
                float4 color  : COLOR;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            CBUFFER_START(UnityPerMaterial)
                float4 _MainTex_ST;
                half4 _Color;
                half _Cutoff;
            CBUFFER_END

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);

            Varyings vert(Attributes input)
            {
                Varyings output = (Varyings)0;
                output.color = input.color;

                UNITY_SETUP_INSTANCE_ID(input);
                UNITY_TRANSFER_INSTANCE_ID(input, output);

                VertexPositionInputs vertexInput = GetVertexPositionInputs(input.positionOS.xyz);
                output.vertex = vertexInput.positionCS;
                output.uv = TRANSFORM_TEX(input.uv, _MainTex);

                return output;
            }

            half4 frag(Varyings input) : SV_Target
            {
                UNITY_SETUP_INSTANCE_ID(input);
                half2 uv = input.uv;
                half4 texColor = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, uv);
                half3 color = texColor.rgb * input.color.rgb;
                half alpha = texColor.a * input.color.a;
                AlphaDiscard(alpha, _Cutoff);

            #ifdef _ALPHAPREMULTIPLY_ON
                color *= alpha;
            #endif
                return half4(color, alpha);
            }
            ENDHLSL
        }
    }
}

效果