Ox00 Surface Shader Syntax
常用的三种输出数据格式:
//Standard output structure of surface shaders is this:
struct SurfaceOutput
{
fixed3 Albedo; // diffuse color
fixed3 Normal; // tangent space normal, if written
fixed3 Emission;
half Specular; // specular power in 0..1 range
fixed Gloss; // specular intensity
fixed Alpha; // alpha for transparencies
};
//Unity 5版本以上, 支持physically based lighting models.
struct SurfaceOutputStandard
{
fixed3 Albedo; // base (diffuse or specular) color
fixed3 Normal; // tangent space normal, if written
half3 Emission;
half Metallic; // 0=non-metal, 1=metal
half Smoothness; // 0=rough, 1=smooth
half Occlusion; // occlusion (default 1)
fixed Alpha; // alpha for transparencies
};
//镜面高光输出
struct SurfaceOutputStandardSpecular
{
fixed3 Albedo; // diffuse color
fixed3 Specular; // specular color
fixed3 Normal; // tangent space normal, if written
half3 Emission;
half Smoothness; // 0=rough, 1=smooth
half Occlusion; // occlusion (default 1)
fixed Alpha; // alpha for transparencies
};
0x01 Surface Shader compile directives
Surface shader编码在CGPROGRAM...ENDCG块内,
- 必须在Subshader块内而不能在pass内部,Surface shader将自己编译成多个通道.
- 必须使用#pragma surface surfaceFunction lightModel [optionalparams] 指令来表明这是surface shader.
拆分#pragma surface surfaceFunction lightModel [optionalparams]
必要参数:
surfaceFunction |
格式void surf (Input IN, inout SurfaceOutput o),Input自定义结构常必须包含纹理坐标和其他自需变量 |
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lightModel |
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surfaceFunction 中Input参数纹理坐标必须带uv或uv2前缀
struct Input
{
float2 uv_MainTex;
floatX 其他变量;
}
其他变量 |
说明 |
float3 viewDir |
视图方向为了计算时差、边缘光照等效果,Input需要包含视图方向 |
float4 color |
每个顶点颜色值 |
float4 screenPos |
屏幕空间位置,为了获得反射效果 |
float3 worldPos |
世界坐标空间 |
float3 worldRefl |
世界空间反射向量,surface shader不能写入o.Normal参数 |
float3 worldNormal |
世界空间法向量,surface shader不能写入o.Normal参数 |
float3 worldRefl;INTERNAL_DATA |
世界坐标反射向量,surface shader必须写入o.Normal参数。基于逐像素法线贴图获得反射向量,请使用WorldReflectionVector(IN,o.Normal) |
float3 worldNormal;INTERNAL_DATA |
世界坐标法线向量,surface shader必须写入o.Normal参数。基于逐像素法线贴图获得反射向量,请使用WorldReflectionVector(IN,o.Normal) |
可选参数:optionalparams
Transparency and alpha testing 使用alpha and alphatest指令 |
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Custom modifier functions用于计算更改输入的顶点数据,或更改最终计算的片元色 |
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Shadows and Tessellation 阴影和网格细分 |
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Code generation options 调整生成着色器代码选项,使得shader更小加载更快 |
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Miscellaneous options 各种其他选项 |
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表面着色器的工作原理
0x02 Surface Shader Light Model
Lighting.cginc
UnityLambertLight |
基于非物理的漫反射 |
LightingLambert |
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LightingLambert_Deferred |
//.. |
LightingLambert_PrePass |
//.. |
UnityBlinnPhongLight |
基于非物理的镜面高光 |
LightingBlinnPhong |
//.. |
LightingBlinnPhong_Deferred |
//.. |
LightingBlinnPhong_PrePass |
//.. |
LightingLambert_GI |
//.. |
LightingBlinnPhong_GI |
//.. |
half4 Lighting<Name> (SurfaceOutput s, UnityGI gi);forward path,不依赖视图方向
half4 Lighting<Name> (SurfaceOutput s, half3 viewDir, UnityGI gi); forward path,依赖视图方向
half4 Lighting<Name>_Deferred (SurfaceOutput s, UnityGI gi, out half4 outDiffuseOcclusion, out half4 outSpecSmoothness, out half4 outNormal); deferred lighting paths
half4 Lighting<Name>_PrePass (SurfaceOutput s, half4 light); Use this in light prepass (legacy deferred) lighting paths. in light prepass (legacy deferred) lighting paths
half4 Lighting<Name>_GI (SurfaceOutput s, UnityGIInput data, inout UnityGI gi);自定义GI解析光照贴图和探针数据
自定义光照函数:
0x03 Example