catlikecoding笔记一：My First Lighting

ObjectSpaceNormal：受DynamicBatching影响，自动合并后法线改变；

WorldSpaceNormal： 法线由ObjectSpace到WorldSpace转换的方法（保持法线的垂直性）：

1.若只包含旋转变换：

i.normal =mul((float3x3)unity_ObjectToWorld,v.normal);

2.若包含旋转和统一缩放（系数k）：

i.normal =mul(（1/k）(float3x3)unity_ObjectToWorld,v.normal);

3.一般：

i.normal=mul(transpose(float3x3)unity_WorldToObject),v.normal);

i.normal=UnityObjectToWorldNormal(v.normal);

Diffuse Shading：

1.Light Source

M199sangeyi05L

worldLight=normalize(_WorldSpaceLightPos0.xyz);

2.Clamped Lighting

dot(worldLight,i.normal);

max(0,dot(worldLight,i.normal));

saturate(0,dot(worldLight,i.normal));

#include "UnityStandardBRDF.cginc"

DotClamped(worldLight,i.normal);

3.LightColor _LightColor0.rgb

4.LightMode LightMode=ForwardBase

5.Albedo

albedo=tex2D(_MainTex,uv).rbg*_Tint.rgb;

diffuse=albedo*lightColor*DotClamped(lightDir,i.normal);

Specular Shading

Phong:

viewDir=normalize(_WorldSpaceCameraPos-i.worldPos);

reflectionDir=reflect(-lightDir,i.normal);

_Gloss：表面光滑度度量，越光滑，高光范围越小[0,100]

specular=_SpecularTint.rgb*lightColor*pow(DotClamped(viewDir,reflectionDir),_Gloss);

Blinn-Phong

halfVec=normalize(lightDir+viewDir);

specular=_SpecularTint.rgb*lightColor*pow(DotClamped(halfVec,i.normal),_Gloss);

Energy Conservation

1.根据高光颜色rgb分量 ;

albedo*=1-_SpecularTint.rgb;

2.根据高光颜色最大分量(monochrome)

albedo*=1-max(_SpecularTint.r,max(_Specular.g,_SpecularTint.b));

3.内置函数

#include "UnityStandardUtils.cginc"

float oneMinusRlflectivity;(用于monochrome)

albedo=EnergyConservationBetweenDiffuseAndSpecular(albedo,_SpecularTint.rgb,oneMinusRlflectivity);

这个函数默认monochrome模式，返回albedo*oneMinusReflectivity;

Metallic Workflow

1.simple

_Metallic

_SpecularTint=albedo*_Metallic;

albedo*=(1-_Metallic);

2.内置

DiffuseAndSpecularFromMetallic(albedo, _Metallic, _SpecularTint, oneMinusReflectivity);

PhysicallyBased Shading

#include "UnityPBSLighting.cginc"

UnityLight light;

light.color = _LightColor0.rgb;

light.dir = lightDir;

light.ndotl = DotClamped(i.normal, lightDir);

UnityIndirect indirectLight;

indirectLight.diffuse = 0;

indirectLight.specular = 0;

UNITY_BRDF_PBS(albedo,_SpecularTint,oneMinusReflectivity,_Gloss,i.normal,viewDir,light,in directLight);