纹理映射-TextureMapping

纹理映射

Shader "Unlit/TextureMapping"
{
    
    Properties
    {
    
        _MainTex ("MainTexture", 2D) = "white" {
    }
        _BaseColor("BaseColor",Color) = (1.0,1.0,1.0,1.0)
    }
    SubShader{
    
        
        Pass{
    
            Tags{
     "LightModel" = "ForwardBase"}
            CGPROGRAM
            #include "Lighting.cginc"
            #pragma vertex Vertex
            #pragma fragment Fragment
            struct a2v {
    
                float4 vertex : POSITION;
                float3 normal : NORMAL;
                float4 texcoord : TEXCOORD0;
            };
            struct v2f{
    
                float4 pos : SV_POSITION;
                float3 worldNormal : TEXCOORD0;
                float2 uv : TEXCOORD1;
            };
            //ST = Scale And Translation 缩放和偏移 _MainTex_ST.xy存储的缩放的值 _MainTex_ST.zw存储的偏移的值
            float4 _MainTex_ST;
            sampler2D _MainTex;
            float4 _BaseColor;
            v2f Vertex(a2v v) {
    
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.worldNormal = UnityObjectToWorldNormal(v.normal);
                //下面两行代码是等价的一个是通过自己计算 一个是通过内置宏来计算 不过都需要声明变量_MainTex.ST
                //o.uv = v.texcoord.xy * MainTex_ST.xy * MainTex_ST.zw;
                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                return o;
            }
            fixed4 Fragment(v2f i) : SV_TARGET{
    
                fixed3 worldNormal = normalize(i.worldNormal);
                fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);
                fixed3 albedo = tex2D(_MainTex,i.uv).xyz * _BaseColor.xyz;
                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
                fixed3 diffuse = _LightColor0.xyz * albedo * saturate(dot(worldNormal,worldLightDir));
                return fixed4(ambient + diffuse,1.0);
            }
            ENDCG
        }
    }
}