Updated SG include with metalness

BakeryDecodeLightmap.hlsl

#define BAKERY_INV_PI        0.31830988618f

sampler2D _RNM0, _RNM1, _RNM2;

void LightmapUV_float(float2 uv, out float2 lightmapUV)
{
    lightmapUV = uv * unity_LightmapST.xy + unity_LightmapST.zw;
}

void DecodeLightmap(float4 lightmap, out float3 result)
{

#ifdef UNITY_LIGHTMAP_FULL_HDR
    float4 decodeInstructions = float4(0.0, 0.0, 0.0, 0.0); // Never used but needed for the interface since it supports gamma lightmaps
#else
    #if defined(UNITY_LIGHTMAP_RGBM_ENCODING)
        float4 decodeInstructions = float4(34.493242, 2.2, 0.0, 0.0); // range^2.2 = 5^2.2, gamma = 2.2
    #else
        float4 decodeInstructions = float4(2.0, 2.2, 0.0, 0.0); // range = 2.0^2.2 = 4.59
    #endif
#endif

	result = DecodeLightmap(lightmap, decodeInstructions);
}

void SampleRNM0_float(float2 lightmapUV, out float3 result)
{
    DecodeLightmap(tex2D(_RNM0, lightmapUV), result);
}

void SampleRNM1_float(float2 lightmapUV, out float3 result)
{
    DecodeLightmap(tex2D(_RNM1, lightmapUV), result);
}

void SampleRNM2_float(float2 lightmapUV, out float3 result)
{
    DecodeLightmap(tex2D(_RNM2, lightmapUV), result);
}

void SampleL1x_float(float2 lightmapUV, out float3 result)
{
    result = tex2D(_RNM0, lightmapUV);
}

void SampleL1y_float(float2 lightmapUV, out float3 result)
{
    result = tex2D(_RNM1, lightmapUV);
}

void SampleL1z_float(float2 lightmapUV, out float3 result)
{
    result = tex2D(_RNM2, lightmapUV);
}

float shEvaluateDiffuseL1Geomerics(float L0, float3 L1, float3 n)
{
    // average energy
    float R0 = L0;

    // avg direction of incoming light
    float3 R1 = 0.5f * L1;

    // directional brightness
    float lenR1 = length(R1);

    // linear angle between normal and direction 0-1
    //float q = 0.5f * (1.0f + dot(R1 / lenR1, n));
    //float q = dot(R1 / lenR1, n) * 0.5 + 0.5;
    float q = dot(normalize(R1), n) * 0.5 + 0.5;

    // power for q
    // lerps from 1 (linear) to 3 (cubic) based on directionality
    float p = 1.0f + 2.0f * lenR1 / R0;

    // dynamic range constant
    // should vary between 4 (highly directional) and 0 (ambient)
    float a = (1.0f - lenR1 / R0) / (1.0f + lenR1 / R0);

    return R0 * (a + (1.0f - a) * (p + 1.0f) * pow(q, p));
}

void BakerySH_float(float3 L0, float3 normalWorld, float2 lightmapUV, out float3 sh)
{
    float3 nL1x = tex2D(_RNM0, lightmapUV) * 2 - 1;
    float3 nL1y = tex2D(_RNM1, lightmapUV) * 2 - 1;
    float3 nL1z = tex2D(_RNM2, lightmapUV) * 2 - 1;
    float3 L1x = nL1x * L0 * 2;
    float3 L1y = nL1y * L0 * 2;
    float3 L1z = nL1z * L0 * 2;

    float lumaL0 = dot(L0, 1);
    float lumaL1x = dot(L1x, 1);
    float lumaL1y = dot(L1y, 1);
    float lumaL1z = dot(L1z, 1);
    float lumaSH = shEvaluateDiffuseL1Geomerics(lumaL0, float3(lumaL1x, lumaL1y, lumaL1z), normalWorld);

    sh = L0 + normalWorld.x * L1x + normalWorld.y * L1y + normalWorld.z * L1z;
    float regularLumaSH = dot(sh, 1);

    sh *= lerp(1, lumaSH / regularLumaSH, saturate(regularLumaSH*16));
}

// Following two functions are copied from the original Unity standard shader for compatibility
// -----
float SmoothnessToPerceptualRoughness(float smoothness)
{
    return (1 - smoothness);
}
float BakeryPerceptualRoughnessToRoughness(float perceptualRoughness)
{
    return perceptualRoughness * perceptualRoughness;
}
float GGXTerm (half NdotH, half roughness)
{
    half a2 = roughness * roughness;
    half d = (NdotH * a2 - NdotH) * NdotH + 1.0f; // 2 mad
    return BAKERY_INV_PI * a2 / (d * d + 1e-7f); // This function is not intended to be running on Mobile,
                                            // therefore epsilon is smaller than what can be represented by half
}
// -----

void DirectionalSpecular_float(float2 lightmapUV, float3 normalWorld, float3 viewDir, float smoothness, out float3 color)
{
#ifdef LIGHTMAP_ON
#ifdef DIRLIGHTMAP_COMBINED
    float4 lmColor = SAMPLE_TEXTURE2D(TEXTURE2D_ARGS(unity_Lightmap, samplerunity_Lightmap), lightmapUV);
    float3 lmDir = SAMPLE_TEXTURE2D(TEXTURE2D_ARGS(unity_LightmapInd, samplerunity_Lightmap), lightmapUV) * 2 - 1;
    float3 halfDir = normalize(normalize(lmDir) + viewDir);
    float nh = saturate(dot(normalWorld, halfDir));
    float perceptualRoughness = SmoothnessToPerceptualRoughness(smoothness);
    float roughness = BakeryPerceptualRoughnessToRoughness(perceptualRoughness);
    float spec = GGXTerm(nh, roughness);
    color = lmColor * spec;
    return;
#endif
#endif
    color = 0;
}

// albedo is only used if metalness > 0
void BakerySpecSH_float(float3 L0, float3 normalWorld, float2 lightmapUV, float3 viewDir, float smoothness, float3 albedo, float metalness,
                                                                                                    out float3 diffuseSH, out float3 specularSH)
{
    float3 nL1x = tex2D(_RNM0, lightmapUV) * 2 - 1;
    float3 nL1y = tex2D(_RNM1, lightmapUV) * 2 - 1;
    float3 nL1z = tex2D(_RNM2, lightmapUV) * 2 - 1;
    float3 L1x = nL1x * L0 * 2;
    float3 L1y = nL1y * L0 * 2;
    float3 L1z = nL1z * L0 * 2;

    float lumaL0 = dot(L0, 1);
    float lumaL1x = dot(L1x, 1);
    float lumaL1y = dot(L1y, 1);
    float lumaL1z = dot(L1z, 1);
    float lumaSH = shEvaluateDiffuseL1Geomerics(lumaL0, float3(lumaL1x, lumaL1y, lumaL1z), normalWorld);

    diffuseSH = L0 + normalWorld.x * L1x + normalWorld.y * L1y + normalWorld.z * L1z;
    float regularLumaSH = dot(diffuseSH, 1);

    diffuseSH *= lerp(1, lumaSH / regularLumaSH, saturate(regularLumaSH*16));
    diffuseSH = max(diffuseSH, 0.0);

    const float3 lumaConv = float3(0.2125f, 0.7154f, 0.0721f);

    float3 dominantDir = float3(dot(nL1x, lumaConv), dot(nL1y, lumaConv), dot(nL1z, lumaConv));
    float focus = saturate(length(dominantDir));
    float3 halfDir = normalize(normalize(dominantDir) - -viewDir);
    float nh = saturate(dot(normalWorld, halfDir));
    float perceptualRoughness = SmoothnessToPerceptualRoughness(smoothness);
    float roughness = BakeryPerceptualRoughnessToRoughness(perceptualRoughness);
    float spec = GGXTerm(nh, roughness);

    specularSH = L0 + dominantDir.x * L1x + dominantDir.y * L1y + dominantDir.z * L1z;

    specularSH = max(spec * specularSH, 0.0);

    // Convert metalness to specular and "oneMinusReflectivity"
    float3 specularColor = lerp(float3(0.04, 0.04, 0.04), albedo, metalness);
    float oneMinusDielectricSpec = 1.0 - 0.04;
    float oneMinusReflectivity = oneMinusDielectricSpec - metalness * oneMinusDielectricSpec;

    // Note: HDRP ShaderGraph will remove metallic parts from diffuse by itself, so we don't do it here

    // Directly apply fresnel and smoothness-dependent grazing term
    float nv = 1.0f - saturate(dot(normalWorld, viewDir));
    float nv2 = nv * nv;
    float fresnel = nv * nv2 * nv2;

    float reflectivity = max(max(specularColor.r, specularColor.g), specularColor.b); // hack, but consistent with Unity code
    float grazingTerm = saturate(smoothness + reflectivity);
    float3 fresnel3 = lerp(specularColor, float3(grazingTerm, grazingTerm, grazingTerm), fresnel);

    specularSH *= fresnel3;
}

void BakerySpecSHFull_float(float3 L0, float3 normalWorld, float2 lightmapUV, float3 viewDir, float smoothness, float3 albedo, float metalness,
                                                                                                    out float3 diffuseSH, out float3 specularSH)
{
    float3 nL1x = tex2D(_RNM0, lightmapUV) * 2 - 1;
    float3 nL1y = tex2D(_RNM1, lightmapUV) * 2 - 1;
    float3 nL1z = tex2D(_RNM2, lightmapUV) * 2 - 1;
    float3 L1x = nL1x * L0 * 2;
    float3 L1y = nL1y * L0 * 2;
    float3 L1z = nL1z * L0 * 2;

    float lumaL0 = dot(L0, 1);
    float lumaL1x = dot(L1x, 1);
    float lumaL1y = dot(L1y, 1);
    float lumaL1z = dot(L1z, 1);
    float lumaSH = shEvaluateDiffuseL1Geomerics(lumaL0, float3(lumaL1x, lumaL1y, lumaL1z), normalWorld);

    diffuseSH = L0 + normalWorld.x * L1x + normalWorld.y * L1y + normalWorld.z * L1z;
    float regularLumaSH = dot(diffuseSH, 1);

    diffuseSH *= lerp(1, lumaSH / regularLumaSH, saturate(regularLumaSH*16));
    diffuseSH = max(diffuseSH, 0.0);

    const float3 lumaConv = float3(0.2125f, 0.7154f, 0.0721f);

    float3 dominantDir = float3(dot(nL1x, lumaConv), dot(nL1y, lumaConv), dot(nL1z, lumaConv));
    float focus = saturate(length(dominantDir));
    float3 halfDir = normalize(normalize(dominantDir) - -viewDir);
    float nh = saturate(dot(normalWorld, halfDir));
    float perceptualRoughness = SmoothnessToPerceptualRoughness(smoothness);
    float roughness = BakeryPerceptualRoughnessToRoughness(perceptualRoughness);
    float spec = GGXTerm(nh, roughness);

    specularSH = L0 + dominantDir.x * L1x + dominantDir.y * L1y + dominantDir.z * L1z;

    specularSH = max(spec * specularSH, 0.0);

    // Convert metalness to specular and "oneMinusReflectivity"
    float3 specularColor = lerp(float3(0.04, 0.04, 0.04), albedo, metalness);
    float oneMinusDielectricSpec = 1.0 - 0.04;
    float oneMinusReflectivity = oneMinusDielectricSpec - metalness * oneMinusDielectricSpec;

    // Directly apply fresnel and smoothness-dependent grazing term
    float nv = 1.0f - saturate(dot(normalWorld, viewDir));
    float nv2 = nv * nv;
    float fresnel = nv * nv2 * nv2;

    float reflectivity = max(max(specularColor.r, specularColor.g), specularColor.b); // hack, but consistent with Unity code
    float grazingTerm = saturate(smoothness + reflectivity);
    float3 fresnel3 = lerp(specularColor, float3(grazingTerm, grazingTerm, grazingTerm), fresnel);

    diffuseSH *= oneMinusReflectivity; // no baked GI override: modify diffuse
    specularSH *= fresnel3;
}