Skyshop代码解析

Posted 2020-11-22 sifenkesi

MarmosetInput.cginc：

Input结构定义：

struct Input
{
       #if defined(MARMO_PACKED_UV) || defined(MARMO_PACKED_VERTEX_OCCLUSION) ||  defined(MARMO_PACKED_VERTEX_COLOR)
              float4 texcoord;
       #else
              float2 texcoord;
       #endif
       
       float3 worldNormal;
       
       #if defined(MARMO_SPECULAR_DIRECT) || defined(MARMO_SPECULAR_IBL)
              float3 viewDir;
       #endif
       
       #if defined(MARMO_COMPUTE_WORLD_POS)
              #ifdef MARMO_U5_WORLD_POS
              float3 worldPos;     //this is free in Unity 5
              #endif
       #else
              float4 worldP;             //lets write our own
       #endif
       #if defined(MARMO_VERTEX_COLOR) || defined(MARMO_VERTEX_LAYER_MASK)
              half4 color : COLOR;
       #elif defined(MARMO_VERTEX_OCCLUSION)
              half2 color : COLOR;
       #endif
       
       #ifdef MARMO_DIFFUSE_VERTEX_IBL
              float3 vertexIBL;
       #endif
       INTERNAL_DATA
};

 

Output结构定义：

struct MarmosetOutput
{
       half3 Albedo; //diffuse map RGB
       half Alpha;          //diffuse map A
       half3 Normal; //world-space normal
       half3 Emission;      //contains IBL contribution
       half Specular;       //specular exponent (required by Unity)
       #ifdef MARMO_SPECULAR_DIRECT
              half3 SpecularRGB;   //specular mask
       #endif
};

Unity自带的Output结构定义：

struct SurfaceOutput
{
    fixed3 Albedo;
    fixed3 Normal;
    fixed3 Emission;
    half Specular;
    fixed Gloss;
    fixed Alpha;
};

// Metallic workflow
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
    // Smoothness is the user facing name, it should be perceptual smoothness but user should not have to deal with it.
    // Everywhere in the code you meet smoothness it is perceptual smoothness
    half Smoothness;    // 0=rough, 1=smooth
    half Occlusion;     // occlusion (default 1)
    fixed Alpha;        // alpha for transparencies
};

// Specular workflow
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
};

 

MarmosetDirect.cginc：

直接光照的主要代码，去掉deferred lighting相关的代码。

#ifndef MARMOSET_DIRECT_CGINC
#define MARMOSET_DIRECT_CGINC
// Core
inline float3 wrapLighting(float DP, float3 scatter)
{
    scatter *= 0.5;
    float3 integral = float3(1.0,1.0,1.0)-scatter;
    float3 light = saturate(DP * integral + scatter);
    float shadow = (DP*0.5+0.5);
    shadow *= shadow;
    return light * integral * shadow;
}
// NOTE: some intricacy in shader compiler on some GLES2.0 platforms (ios) needs ‘viewDir‘ & ‘h‘
// to be mediump instead of lowp, otherwise specular highlight becomes too bright.
inline half4 marmosetLighting (MarmosetOutput s, half3 viewDir, half3 lightDir, half3 lightColor)
{
    half4 frag = half4(0.0,0.0,0.0,s.Alpha);        
    #if defined(MARMO_DIFFUSE_DIRECT) || defined(MARMO_SPECULAR_DIRECT)
        half3 L = lightDir;
        half3 N = s.Normal;
        #ifdef MARMO_HQ
            L = normalize(L);
        #endif
    #endif
        
    #ifdef MARMO_DIFFUSE_DIRECT
        half dp = saturate(dot(N,L));
        
        #ifdef MARMO_DIFFUSE_SCATTER
            float4 scatter = _Scatter * _ScatterColor;
            half3 diff = wrapLighting(dp, scatter.rgb);
            diff *= 2.0 * s.Albedo.rgb; //*2.0 to match Unity
        #else
            half3 diff = (2.0 * dp) * s.Albedo.rgb; //*2.0 to match Unity
        #endif
        frag.rgb = diff * lightColor;
    #endif
    
    #ifdef MARMO_SPECULAR_DIRECT
        half3 H = normalize(viewDir+L);
        float specRefl = saturate(dot(N,H));
        half3 spec = pow(specRefl, s.Specular*512.0);
        #ifdef MARMO_HQ
            //self-shadowing blinn
            #ifdef MARMO_DIFFUSE_DIRECT
                spec *= saturate(10.0*dp);
            #else
                spec *= saturate(10.0*dot(N,L));
            #endif
        #endif
        spec *= lightColor;
        frag.rgb += (0.5 * spec) * s.SpecularRGB; //*0.5 to match Unity
    #endif
    return frag;
}
//forward lighting
inline half4 LightingMarmosetDirect( MarmosetOutput s, half3 lightDir, half3 viewDir, half atten )
{
    return marmosetLighting( s, viewDir, lightDir, _LightColor0 * atten);
}
inline half4 LightingMarmosetDirect( MarmosetOutput s, half3 viewDir, UnityGI gi )
{
    fixed4 c;
    c = marmosetLighting (s, viewDir, gi.light.dir, gi.light.color);
    
    #ifdef UNITY_LIGHT_FUNCTION_APPLY_INDIRECT
        c.rgb += s.Albedo * gi.indirect.diffuse;
    #endif
    return c;
}
inline void LightingMarmosetDirect_GI (MarmosetOutput s, UnityGIInput giInput, inout UnityGI gi)
{
    gi = UnityGlobalIllumination(giInput, 1.0, s.Normal);
}
#endif

 

MarmosetSurf.cginc：

旧版本的surf代码：

#ifndef MARMOSET_SURF_CGINC
#define MARMOSET_SURF_CGINC
void MarmosetSurf(Input IN, inout MarmosetOutput OUT)
{
       #define uv_diff IN.uv_MainTex
       #define uv_spec IN.uv_MainTex
       #define uv_bump IN.uv_MainTex
       #define uv_glow IN.uv_MainTex
       //DIFFUSE
       #if defined(MARMO_DIFFUSE_DIRECT) || defined(MARMO_DIFFUSE_IBL)
              half4 diff = tex2D( _MainTex, uv_diff );
              diff *= _Color;
              //camera exposure is built into OUT.Albedo
              diff.rgb *= _ExposureIBL.w;
              OUT.Albedo = diff.rgb;
              OUT.Alpha = diff.a;
              #ifdef MARMO_PREMULT_ALPHA
                     OUT.Albedo *= diff.a;
              #endif
       #else
              OUT.Albedo = half3(0.0,0.0,0.0);
              OUT.Alpha = 1.0;
       #endif
       
       //NORMALS
       #ifdef MARMO_NORMALMAP
              float3 N = UnpackNormal(tex2D(_BumpMap,uv_bump));
              #ifdef MARMO_HQ
                     N = normalize(N);
              #endif
              OUT.Normal = N; //N is in tangent-space
       #else
              //OUT.Normal is not modified when not normalmapping
              float3 N = OUT.Normal; //N is in world-space
              #ifdef MARMO_HQ
                     N = normalize(N);
              #endif
       #endif
       
       //SPECULAR
       #if defined(MARMO_SPECULAR_DIRECT) || defined(MARMO_SPECULAR_IBL)
              half4 spec = tex2D(_SpecTex, uv_spec);
              float3 E = IN.viewDir; //E is in whatever space N is
              #ifdef MARMO_HQ
                     E = normalize(E);
                     half fresnel = splineFresnel(N, E, _SpecInt, _Fresnel);
              #else
                     half fresnel = fastFresnel(N, E, _SpecInt, _Fresnel);         
              #endif
              
              //camera exposure is built into OUT.Specular
              spec.rgb *= _SpecColor.rgb * fresnel * _ExposureIBL.w;
              OUT.Specular = spec.rgb;
              half glossLod = glossLOD(spec.a, _Shininess);
              OUT.Gloss = glossExponent(glossLod);
              //conserve energy by dividing out specular integral
              OUT.Specular *= specEnergyScalar(OUT.Gloss);
       #endif
       
       //SPECULAR IBL
       #ifdef MARMO_SPECULAR_IBL
              #ifdef MARMO_NORMALMAP
                     float3 R = WorldReflectionVector(IN, OUT.Normal);
              #else
                     float3 R = IN.worldRefl;
              #endif
              #ifdef MARMO_SKY_ROTATION
                     R = mulVec3(_SkyMatrix,R); //per-fragment matrix multiply,  expensive
              #endif
              #ifdef MARMO_MIP_GLOSS
                     half3 specIBL = glossCubeLookup(_SpecCubeIBL, R, glossLod);
              #else
                     half3 specIBL = specCubeLookup(_SpecCubeIBL, R)*spec.a;
              #endif
              OUT.Emission += specIBL.rgb * spec.rgb * _ExposureIBL.y;
       #endif
       
       //DIFFUSE IBL
       #ifdef MARMO_DIFFUSE_IBL
              N = WorldNormalVector(IN,N); //N is in world-space
              #ifdef MARMO_SKY_ROTATION
                     N = mulVec3(_SkyMatrix,N); //per-fragment matrix multiply,  expensive
              #endif
              half3 diffIBL = diffCubeLookup(_DiffCubeIBL, N);
              OUT.Emission += diffIBL * diff.rgb * _ExposureIBL.x;
       #endif
       
       
       //GLOW
       #ifdef MARMO_GLOW
              half4 glow = tex2D(_Illum, uv_glow);
              glow.rgb *= _GlowColor.rgb;
              glow.rgb *= _GlowStrength;
              glow.a *= _EmissionLM;
              glow.rgb += OUT.Albedo * glow.a;
              OUT.Emission += glow.rgb * _ExposureIBL.w;
       #endif
}
#endif

IBL实现的两个关键函数：

half3 diffCubeLookup(samplerCUBE diffCube, float3 worldNormal)
{
       half4 diff = texCUBE(diffCube, worldNormal);
       return fromRGBM(diff);
}
half3 specCubeLookup(samplerCUBE specCube, float3 worldRefl)
{
       half4 spec = texCUBE(specCube, worldRefl);
       return fromRGBM(spec);
}

    IBL.diffuse使用world normal查询，IBL.specular使用world reflection查询。

 

宏定义解析：

MARMO_DIFFUSE_SPECULAR_COMBINED 

    Diffuse/Specular合并

    _MainTex.RGBA = RGB表示Diffuse，A表示Specular强度和Gloss

MARMO_PACKED_UV

    UV打包

#ifdef MARMO_PACKED_UV
    o.texcoord.zw = v.texcoord1.xy;
#endif

MARMO_PACKED_VERTEX_COLOR

    顶点色打包

#ifdef MARMO_PACKED_VERTEX_COLOR            
    o.texcoord.zw = v.color.rg;
    o.worldP.w = v.color.b;
#endif