# Shader-基础纹理-凹凸映射

### 法线纹理

#### 实现在切线空间下的凹凸纹理

```Shader "Unlit/SingleTexture"
{
Properties{
_Color("Color Tint",Color) = (1,1,1,1)
_MainMap("Main Tex", 2D) = "white"{}
_BumpMap("NormalMap",2D) = "bump"{}
_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 = mul(UNITY_MATRIX_MVP, 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;
o.lightDir = mul(rotation, ObjSpaceLightDir(v.vertex)).xyz;
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;

tangentNormal.xy = (packedNormal.xy * 2 - 1)* _BumpScale;
tangentNormal.z = sqrt(1.0 - saturate(dot(tangentNormal.xy, tangentNormal.xy)));

/*tangentnormal = 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 * albedo;
fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(tangentNormal, tangentLightDir));
fixed3 halfDir = normalize(tangentLightDir + tangentViewDir);

float temp = max(0, dot(tangentNormal, halfDir));
fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(temp, _Gloss);
return fixed4(ambient + diffuse + specular, 1.0);
}
ENDCG
}
}
}```

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