## 基本光照模型实现-高光反射

#### 高光反射计算公式

Phong模型

cspecular=(clightmspecular)max(0,v^r^)mgloss

r^=l^2(n^l^)n^

Blinn-Phong模型

cspecular=(clightmspecular)max(0,n^h^)mgloss

h^=v^+l^|v^+l^|

#### 源码-逐顶点

Shader "Custom/SpecularVertexLevel" {
Properties {
_Diffuse ("Diffuse", Color) = (1, 1, 1, 1)
_Specular ("Specular", Color) = (1, 1, 1, 1)
_Gloss ("Gloss", Range(8.0, 256)) = 20
}
Pass {
Tags { "LightMode"="ForwardBase" }

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"

fixed4 _Diffuse;
fixed4 _Specular;
float _Gloss;

struct a2v{
float4 vertex : POSITION;
float3 normal : NORMAL;
};

struct v2f{
float4 pos : SV_POSITION;
float3 color : COLOR;
};

v2f vert(a2v v){
v2f o;

o.pos = UnityObjectToClipPos(v.vertex);

fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;

fixed3 worldNormal = normalize(mul(v.normal, (float3x3)unity_WorldToObject));

fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);

fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));

fixed3 reflectDir = normalize(reflect(-worldLightDir, worldNormal));

fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - mul(unity_ObjectToWorld, v.vertex).xyz);

fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(reflectDir, viewDir)), _Gloss);

o.color = ambient + diffuse + specular;

return o;
}

fixed4 frag(v2f i): SV_Target{
return fixed4(i.color, 1.0);
}

ENDCG
}
}
FallBack "Speculr"
}

#### 源码-逐像素

Shader "Custom/SpecularPixelLevel" {
Properties {
_Diffuse ("Diffuse", Color) = (1, 1, 1, 1)
_Specular ("Specular", Color) = (1, 1, 1, 1)
_Gloss ("Gloss", Range(8.0, 256)) = 20
}
Pass {
Tags { "LightMode"="ForwardBase" }

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"

fixed4 _Diffuse;
fixed4 _Specular;
float _Gloss;

struct a2v{
float4 vertex : POSITION;
float3 normal : NORMAL;
};

struct v2f{
float4 pos : SV_POSITION;
float3 worldNormal : TEXCOORD0;
float3 worldPos : TEXCOORD1;
};

v2f vert(a2v v){
v2f o;

o.pos = UnityObjectToClipPos(v.vertex);

o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);

o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;

return o;

}

fixed4 frag(v2f i): SV_Target{
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;

fixed3 worldNormal = normalize(i.worldNormal);

fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);

fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));

fixed3 reflectDir = normalize(reflect(-worldLightDir, worldNormal));

fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos.xyz);

fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(reflectDir, viewDir)), _Gloss);

return fixed4(ambient + diffuse + specular, 1.0);
}

ENDCG
}
}
FallBack "Speculr"
}


#### Blin-Phong逐像素

Shader "Custom/BlinnPhong" {
Properties {
_Diffuse ("Diffuse", Color) = (1, 1, 1, 1)
_Specular ("Specular", Color) = (1, 1, 1, 1)
_Gloss ("Gloss", Range(8.0, 256)) = 20
}
Pass {
Tags { "LightMode"="ForwardBase" }

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"

fixed4 _Diffuse;
fixed4 _Specular;
float _Gloss;

struct a2v{
float4 vertex : POSITION;
float3 normal : NORMAL;
};

struct v2f{
float4 pos : SV_POSITION;
float3 worldNormal : TEXCOORD0;
float3 worldPos : TEXCOORD1;
};

v2f vert(a2v v){
v2f o;

o.pos = UnityObjectToClipPos(v.vertex);

o.worldNormal = mul(v.normal, (float3x3)unity_WorldToObject);

o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;

return o;

}

fixed4 frag(v2f i): SV_Target{
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;

fixed3 worldNormal = normalize(i.worldNormal);

fixed3 worldLightDir = normalize(_WorldSpaceLightPos0.xyz);

fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, worldLightDir));

//fixed3 reflectDir = normalize(reflect(-worldLightDir, worldNormal));

fixed3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldPos.xyz);

fixed3 halfDir = normalize(worldLightDir + viewDir);

fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(saturate(dot(worldNormal, halfDir)), _Gloss);

return fixed4(ambient + diffuse + specular, 1.0);
}

ENDCG
}
}
FallBack "Speculr"
}