//基础纹理
//凹凸映射：使用一张纹理来修改模型表面的法线
//世界空间中的计算
Shader "Unity shader book/Chapter 7/NormalMapWorldSpace" {
Properties {
_Color("Color Tint",Color)=(1,1,1,1)
_MainTex("Main Tex",2D) = "white"{}
_BumpMap("Normal Map",2D) = "bump"{}//bump内置的法线纹理，当没有提供任何法线纹理时，对应模型自带的法线信息
_BumpScale("Bump Scale",Float) = 1.0//控制凹凸程度
_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" //包含文件，为了使用一些变量 如_LightColor0
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;//tanget.w福切线方向
float4 texcoord:TEXCOORD0;
};
struct v2f {
float4 pos:SV_POSITION;
float4 uv:TEXCOORD0;
float4 TtoW0:TEXCOORD1;
float4 TtoW1:TEXCOORD2;
float4 TtoW2:TEXCOORD3;
};
//修改顶点着色器 计算从切线空间到世界空间的变化
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.xy = TRANSFORM_TEX(v.texcoord,_MainTex);
o.uv.zw = v.texcoord.xy*_BumpMap_ST.xy + _BumpMap_ST.zw;
//o.uv.zw=TRANSFORM_TEX(v.texcoord,_BumpMap);
float3 worldPos = mul(unity_ObjectToWorld,v.vertex).xyz;
fixed3 worldNormal = UnityObjectToWorldNormal(v.normal);
fixed3 worldTangent = UnityObjectToWorldDir(v.tangent.xyz);
fixed3 worldBinormal = cross(worldNormal, worldTangent)*v.tangent.w;//
//把他们按列放到从切线空间到世界空间的变换矩阵，然后分别存储在3个变量中。
o.TtoW0 = float4(worldTangent.x,worldBinormal.x,worldNormal.x,worldPos.x);
o.TtoW1 = float4(worldTangent.y, worldBinormal.y, worldNormal.y, worldPos.y);
o.TtoW2 = float4(worldTangent.z, worldBinormal.z, worldNormal.z, worldPos.z);
return o;
}
fixed4 frag(v2f i) :SV_Target{
float3 worldPos = float3(i.TtoW0.w,i.TtoW1.w,i.TtoW2.w);
fixed3 lightDir = normalize(UnityWorldSpaceLightDir(worldPos));
fixed3 viewDir = normalize(UnityWorldSpaceViewDir(worldPos));
fixed3 bump = UnpackNormal(tex2D(_BumpMap,i.uv.zw));
bump.xy *= _BumpScale;
bump.z = sqrt(1.0-saturate(dot(bump.xy,bump.xy)));
bump = normalize(half3(dot(i.TtoW0.xyz,bump),dot(i.TtoW1.xyz,bump),dot(i.TtoW2.xy,bump)));
fixed3 albedo = tex2D(_MainTex,i.uv).rgb * _Color.rgb;
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;
fixed3 diffuse = _LightColor0.rgb * albedo * max(0,dot(bump, lightDir));
fixed3 halfDir = normalize(lightDir+ viewDir);
fixed3 specular = _LightColor0.rgb *_Specular.rgb*pow(max(0,dot(bump,halfDir)), _Gloss);
return fixed4(ambient + diffuse + specular, 1.0);
}
ENDCG
}
}
FallBack "Specular"
}