接收阴影时可调阴影颜色

Shader "DiffuseEmission" {
    Properties{
        _MainTex("Base (RGB)", 2D) = "white" {}
        _Color("MainColor", Color) = (0.9,0.9,0.9,0)
        _ShadowColor("ShadowColor", Color) = (0.15,0.15,0.15,0)
        _Emission("Emission", Range(0, 1)) = 0
        _ShadowStrength("ShadowStrength",Range(0, 1)) = 0.5
    }
        SubShader{
            Tags { "RenderType" = "Opaque" "Queue"="Geometry"}
            LOD 150
            pass{
            Tags { "LightMode"="ForwardBase" }
        CGPROGRAM
        
        #pragma multi_compile_fwdbase
        #pragma vertex vert
        #pragma fragment frag
        #include "Lighting.cginc"
        #include "AutoLight.cginc"
        #include "UnityCG.cginc"
    
        
        sampler2D _MainTex;
        half4 _MainTex_ST;
        float _Emission;
        float4 _Color;
        half _ShadowStrength;
        float3 _ShadowColor;
            struct a2v {
                half4 vertex : POSITION;
                half4 texcoord : TEXCOORD0;
                float3 normal : NORMAL;
                    };
            
            struct v2f {
                half4 pos : SV_POSITION;
                half4 uv : TEXCOORD0;
                float3 worldNormal : TEXCOORD2;
                float3 worldPos : TEXCOORD1;
                SHADOW_COORDS(3)
            };
            v2f vert(a2v v) {
                v2f o;
                UNITY_INITIALIZE_OUTPUT(v2f, o);
                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw; 
                o.worldNormal = UnityObjectToWorldNormal(v.normal);
                o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
                TRANSFER_SHADOW(o);
                
                return o;
            }


            fixed4 frag(v2f i) : SV_Target {
                fixed3 worldNormal = normalize(i.worldNormal);
                fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
                fixed4 c = tex2D(_MainTex, i.uv.xy) * _Color + _Emission;
                fixed3 diffuse =  c * max(0, dot(worldNormal, worldLightDir)) + _ShadowColor *  (1- dot(worldNormal, worldLightDir));
                fixed atten = SHADOW_ATTENUATION(i);
             
                                                                
             // return   half4(diffuse * (1 - (1 - atten) *  _ShadowStrength ),1.0);
            return half4(diffuse * (1 - (1 - atten) *  _ShadowStrength ) /*+ _ShadowColor*/,1.0);
                }
        ENDCG
        }
        }
        Fallback "Diffuse"