光照模型

Shader "LitSphere"{    Properties    {        _MainTex("MainTex", 2D) = "white" {}        _MianTint("MainTint", Color) = (1, 1, 1, 1)        _NormalMap("NormalMap", 2D) = "bump" {}    }    SubShader    {        Tags        {            "RenderType" = "Opaque"        }        LOD 200        CGPROGRAM        #pragma surface surf Unlit vertex : vert        inline half4 LightingUnlit(SurfaceOutput s, fixed3 lightDir, fixed atten)        {            half4 c = half4(1, 1, 1, 1);            c.rgb = s.Albedo;            c.a = s.Alpha;            return c;        }        sampler2D _MainTex;        float4 _MainTint;        sampler2D _NormalMap;        struct Input        {            float2 uv_MainTex;            float2 uv_NormalMap;            float3 tan1;            float3 tan2;        };        void vert(inout appdata_full v, out Input o)        {            UNITY_INITIALIZE_OUTPUT(Input, o);            TANGENT_SPACE_ROTATION;            o.tan1 = mul(rotation, UNITY_MATRIX_IT_MV[0].xyz);            o.tan2 = mul(rotation, UNITY_MATRIX_IT_MV[1].xyz);        }        void surf(Input IN, inout SurfaceOutput o)        {            float3 normals = UnpackNormal(tex2D(_NormalMap, IN.uv_NormalMap));            o.Normal = normals;            float2 litSphereUV;            litSphereUV.x = dot(IN.tan1, o.Normal);            litSphereUV.y = dot(IN.tan2, o.Normal);             half4 c = tex2D(_MainTex, litSphereUV * 0.5 + 0.5);             o.Albedo = c.rgb * _MainTint;             o.Alpha = c.a;        }        ENDCG    }}