【Unity Shader】切线空间下计算凹凸映射

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'Shader "Unlit/NormalTangent"
{Properties{_Color("Color Tint", Color) = (1, 1, 1, 1)_MainTex("Main Tex", 2D) = "While"{}//法线纹理_BumpMap("Normal Map", 2D) = "bump"{}//控制凹凸程度，为0时意味该法线纹理不会对光照产生任何影响_BumpScale("Bump Scale", Float) = 1.0_Specular("Specular", Color) = (1,1,1,1)_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;float4 _MainTex_ST;sampler2D _BumpMap;float4 _BumpMap_ST;float _BumpScale;fixed4 _Specular;float _Gloss;struct a2v{float4 vertex : POSITION;float3 normal : NORMAL;float4 tangent : TANGENT;float4 texcoord : TEXCOORD0;};struct v2f{float4 pos : SV_POSITION;float4 uv : TEXCOORD0;float3 lightDir : TEXCOORD1;float3 viewDir : TEXCOORD2;};v2f vert(a2v v){v2f o;o.pos = UnityObjectToClipPos(v.vertex);o.uv.xy = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw;o.uv.zw = v.texcoord.xy * _BumpMap_ST.xy + _BumpMap_ST.zw;TANGENT_SPACE_ROTATION;//将光照方向从模型空间转换到切线空间中，ObjSpaceLightDir是内置函数，得到模型空间中的光照o.lightDir = mul(rotation, ObjSpaceLightDir(v.vertex)).xyz;//将视角方向从模型空间转换到切线空间中，ObjSpaceViewDir是内置函数，得到模型空间中的视角方向o.viewDir = mul(rotation, ObjSpaceViewDir(v.vertex)).xyz;return o;}fixed4 frag(v2f i) : SV_Target{fixed3 tangentLightDir = normalize(i.lightDir);fixed3 tangentViewDir = normalize(i.viewDir);fixed4 packedNormal = tex2D(_BumpMap, i.uv.zw);fixed3 tangentNormal;//如果没有在Unity中把该法线纹理类型设置成Normal map//tangentNormal.xy = (packedNormal.xy * 2 - 1) * _BumpScale;//tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));//如果设置了Normal maptangentNormal = UnpackNormal(packedNormal);tangentNormal.xy *= _BumpScale;tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));fixed3 albedo = tex2D(_MainTex, i.uv).rgb * _Color.rgb;fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(tangentNormal, tangentLightDir));fixed3 halfDir = normalize(tangentLightDir + tangentViewDir);fixed3 specular = _LightColor0.rgb * _Specular * pow(max(0, dot(tangentNormal, halfDir)), _Gloss);return fixed4(ambient + diffuse +specular, 1.0);}ENDCG}}Fallback "Specular"
}