Shader自学笔记 3.3.1 采样渐变纹理应用于BlinnPhong光照模型

Shader "Custom/texture/test1" {//  定义纹理属性    Properties {        _Color ("Color", Color) = (1,1,1,1)        _MainTex ("Main Tex", 2D) = "white" {}        _Specular("Specular",Color)=(1,1,1)        _Gloss ("Gloss", Range(8.0,256)) = 20        }    SubShader {    Pass{        Tags { "LightMode"="ForwardBase" }        CGPROGRAM        #pragma vertex vert        #pragma fragment frag        #include "Lighting.cginc"        fixed4 _Color;        sampler2D _MainTex;//      纹理缩放平移属性        float4 _MainTex_ST;        fixed4 _Specular;        float _Gloss;        struct a2v{        float4 vertex: POSITION;        float3 normal:NORMAL;//      语义指定第一个纹理        float4 texcoord:TEXCOORD0;        };        struct v2f{        float4 pos:SV_POSITION;        float3 worldNormal:TEXCOORD0;        float3 worldPos:TEXCOORD1;        float2 uv:TEXCOORD2;        };        v2f vert(a2v v){        v2f o;        o.pos=mul(UNITY_MATRIX_MVP,v.vertex);        o.worldNormal=UnityObjectToWorldNormal(v.normal);        o.worldPos=mul(unity_ObjectToWorld,v.vertex).xyz;//      _MainTex_ST xy为缩放，zw为偏移        o.uv=v.texcoord.xy*_MainTex_ST.xy+_MainTex_ST.zw;//      也可以直接用内建函数//      o.uv=TRANSFORM_TEX(v.texcoord,_MainTex);        return o;        }        fixed4 frag(v2f i):SV_Target{        fixed3 worldNormal=normalize(i.worldNormal);        fixed3 worldLightDir=normalize(UnityWorldSpaceLightDir(i.worldPos));//      使用纹理采样漫反射颜色        fixed halfLambert=0.5*dot(worldNormal,worldLightDir)+0.5;        fixed3 diffuseColor=tex2D(_MainTex,fixed2(halfLambert,halfLambert)).rgb*_Color.rgb;        fixed3 ambient=UNITY_LIGHTMODEL_AMBIENT.xyz;//      fixed3 diffuse=_LightColor0.rgb*diffuseColor;//      fixed3 albedo=tex2D(_MainTex,i.uv).rgb*_Color.rgb;//      fixed3 ambient=UNITY_LIGHTMODEL_AMBIENT.xyz*albedo;//      fixed3 diffuse=_LightColor0.rgb*albedo*max(0,dot(worldNormal,worldLightDir));        fixed3 viewDir=normalize(UnityWorldSpaceViewDir(i.worldPos));        fixed3 halfDir=normalize(worldLightDir+viewDir);//      BlinnPhon光照模型        fixed3 specular=_LightColor0.rgb*_Specular.rgb*pow(max(0,dot(worldNormal,halfDir)),_Gloss);        return fixed4(ambient+diffuseColor+specular,1.0);        }        ENDCG        }    }    FallBack "Specular"}