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#ifndef LIGHTWEIGHT_LIGHTING_INCLUDED
#define LIGHTWEIGHT_LIGHTING_INCLUDED
#include "LightweightCore.cginc"
#include "LightweightShadows.cginc"
#define PI 3.14159265359f
#define kDieletricSpec half4(0.04, 0.04, 0.04, 1.0 - 0.04) // standard dielectric reflectivity coef at incident angle (= 4%)
#define MAX_VISIBLE_LIGHTS 16
#ifndef UNITY_SPECCUBE_LOD_STEPS
#define UNITY_SPECCUBE_LOD_STEPS 6
#endif
#ifdef NO_ADDITIONAL_LIGHTS
#undef _ADDITIONAL_LIGHTS
#endif
// If lightmap is not defined than we evaluate GI (ambient + probes) from SH
// We might do it fully or partially in vertex to save shader ALU
#if !defined(LIGHTMAP_ON)
#if SHADER_TARGET < 30
// Evaluates SH fully in vertex
#define EVALUATE_SH_VERTEX
#else
// Evaluates L2 SH in vertex and L0L1 in pixel
#define EVALUATE_SH_MIXED
#endif
#endif
// Main light initialized without indexing
#define INITIALIZE_MAIN_LIGHT(light) \
light.pos = _MainLightPosition; \
light.color = _MainLightColor; \
light.distanceAttenuation = _MainLightDistanceAttenuation; \
light.spotDirection = _MainLightSpotDir; \
light.spotAttenuation = _MainLightSpotAttenuation
// Indexing might have a performance hit for old mobile hardware
#define INITIALIZE_LIGHT(light, i) \
half4 indices = (i < 4) ? unity_4LightIndices0 : unity_4LightIndices1; \
int index = (i < 4) ? i : i - 4; \
int lightIndex = indices[index]; \
light.pos = _AdditionalLightPosition[lightIndex]; \
light.color = _AdditionalLightColor[lightIndex]; \
light.distanceAttenuation = _AdditionalLightDistanceAttenuation[lightIndex]; \
light.spotDirection = _AdditionalLightSpotDir[lightIndex]; \
light.spotAttenuation = _AdditionalLightSpotAttenuation[lightIndex]
CBUFFER_START(_PerObject)
half4 unity_LightIndicesOffsetAndCount;
half4 unity_4LightIndices0;
half4 unity_4LightIndices1;
CBUFFER_END
CBUFFER_START(_PerCamera)
sampler2D _MainLightCookie;
float4 _MainLightPosition;
half4 _MainLightColor;
half4 _MainLightDistanceAttenuation;
half4 _MainLightSpotDir;
half4 _MainLightSpotAttenuation;
float4x4 _WorldToLight;
half4 _AdditionalLightCount;
float4 _AdditionalLightPosition[MAX_VISIBLE_LIGHTS];
half4 _AdditionalLightColor[MAX_VISIBLE_LIGHTS];
half4 _AdditionalLightDistanceAttenuation[MAX_VISIBLE_LIGHTS];
half4 _AdditionalLightSpotDir[MAX_VISIBLE_LIGHTS];
half4 _AdditionalLightSpotAttenuation[MAX_VISIBLE_LIGHTS];
CBUFFER_END
CBUFFER_START(_PerFrame)
half4 _GlossyEnvironmentColor;
CBUFFER_END
// Must match Lightweigth ShaderGraph master node
struct SurfaceData
{
half3 albedo;
half3 specular;
half metallic;
half smoothness;
half3 normal;
half3 emission;
half occlusion;
half alpha;
};
struct LightInput
{
float4 pos;
half4 color;
half4 distanceAttenuation;
half4 spotDirection;
half4 spotAttenuation;
};
struct BRDFData
{
half3 diffuse;
half3 specular;
half perceptualRoughness;
half roughness;
half grazingTerm;
};
half ReflectivitySpecular(half3 specular)
{
#if (SHADER_TARGET < 30)
// SM2.0: instruction count limitation
return specular.r; // Red channel - because most metals are either monocrhome or with redish/yellowish tint
#else
return max(max(specular.r, specular.g), specular.b);
#endif
}
half OneMinusReflectivityMetallic(half metallic)
{
// We'll need oneMinusReflectivity, so
// 1-reflectivity = 1-lerp(dielectricSpec, 1, metallic) = lerp(1-dielectricSpec, 0, metallic)
// store (1-dielectricSpec) in kDieletricSpec.a, then
// 1-reflectivity = lerp(alpha, 0, metallic) = alpha + metallic*(0 - alpha) =
// = alpha - metallic * alpha
half oneMinusDielectricSpec = kDieletricSpec.a;
return oneMinusDielectricSpec - metallic * oneMinusDielectricSpec;
}
inline void InitializeBRDFData(half3 albedo, half metallic, half3 specular, half smoothness, half alpha, out BRDFData outBRDFData)
{
#ifdef _SPECULAR_SETUP
half reflectivity = ReflectivitySpecular(specular);
half oneMinusReflectivity = 1.0 - reflectivity;
outBRDFData.diffuse = albedo * (half3(1.0h, 1.0h, 1.0h) - specular);
outBRDFData.specular = specular;
#else
half oneMinusReflectivity = OneMinusReflectivityMetallic(metallic);
half reflectivity = 1.0 - oneMinusReflectivity;
outBRDFData.diffuse = albedo * oneMinusReflectivity;
outBRDFData.specular = lerp(kDieletricSpec.rgb, albedo, metallic);
#endif
outBRDFData.grazingTerm = saturate(smoothness + reflectivity);
outBRDFData.perceptualRoughness = 1.0h - smoothness;
outBRDFData.roughness = outBRDFData.perceptualRoughness * outBRDFData.perceptualRoughness;
#ifdef _ALPHAPREMULTIPLY_ON
outBRDFData.diffuse *= alpha;
alpha = alpha * oneMinusReflectivity + reflectivity;
#endif
}
half3 GlossyEnvironment(half3 reflectVector, half perceptualRoughness)
{
#if !defined(_GLOSSYREFLECTIONS_OFF)
half roughness = perceptualRoughness * (1.7 - 0.7 * perceptualRoughness);
half mip = roughness * UNITY_SPECCUBE_LOD_STEPS;
half4 rgbm = UNITY_SAMPLE_TEXCUBE_LOD(unity_SpecCube0, reflectVector, mip);
return DecodeHDR(rgbm, unity_SpecCube0_HDR);
#endif
return _GlossyEnvironmentColor;
}
half3 LightweightEnvironmentBRDF(BRDFData brdfData, half3 indirectDiffuse, half3 indirectSpecular, half roughness2, half fresnelTerm)
{
half3 c = indirectDiffuse * brdfData.diffuse;
float surfaceReduction = 1.0 / (roughness2 + 1.0);
c += surfaceReduction * indirectSpecular * lerp(brdfData.specular, brdfData.grazingTerm, fresnelTerm);
return c;
}
// Based on Minimalist CookTorrance BRDF
// Implementation is slightly different from original derivation: http://www.thetenthplanet.de/archives/255
//
// * NDF [Modified] GGX
// * Modified Kelemen and Szirmay-​Kalos for Visibility term
// * Fresnel approximated with 1/LdotH
half3 LightweightBDRF(BRDFData brdfData, half roughness2, half3 normal, half3 lightDirection, half3 viewDir)
{
#ifndef _SPECULARHIGHLIGHTS_OFF
half3 halfDir = SafeNormalize(lightDirection + viewDir);
half NoH = saturate(dot(normal, halfDir));
half LoH = saturate(dot(lightDirection, halfDir));
// GGX Distribution multiplied by combined approximation of Visibility and Fresnel
// See "Optimizing PBR for Mobile" from Siggraph 2015 moving mobile graphics course
// https://community.arm.com/events/1155
half d = NoH * NoH * (roughness2 - 1.h) + 1.00001h;
half LoH2 = LoH * LoH;
half specularTerm = roughness2 / ((d * d) * max(0.1h, LoH2) * (brdfData.roughness + 0.5h) * 4);
// on mobiles (where half actually means something) denominator have risk of overflow
// clamp below was added specifically to "fix" that, but dx compiler (we convert bytecode to metal/gles)
// sees that specularTerm have only non-negative terms, so it skips max(0,..) in clamp (leaving only min(100,...))
#if defined (SHADER_API_MOBILE)
specularTerm = specularTerm - 1e-4h;
#endif
#if defined (SHADER_API_MOBILE)
specularTerm = clamp(specularTerm, 0.0, 100.0); // Prevent FP16 overflow on mobiles
#endif
half3 color = specularTerm * brdfData.specular + brdfData.diffuse;
return color;
#else
return brdfData.diffuse;
#endif
}
half3 LightingLambert(half3 lightColor, half3 lightDir, half3 normal)
{
half NdotL = saturate(dot(normal, lightDir));
return lightColor * NdotL;
}
half3 LightingSpecular(half3 lightColor, half3 lightDir, half3 normal, half3 viewDir, half4 specularGloss, half shininess)
{
half3 halfVec = SafeNormalize(lightDir + viewDir);
half NdotH = saturate(dot(normal, halfVec));
half3 specularReflection = specularGloss.rgb * pow(NdotH, shininess) * specularGloss.a;
return lightColor * specularReflection;
}
half CookieAttenuation(float3 worldPos)
{
#ifdef _MAIN_LIGHT_COOKIE
#ifdef _MAIN_DIRECTIONAL_LIGHT
float2 cookieUV = mul(_WorldToLight, float4(worldPos, 1.0)).xy;
return tex2D(_MainLightCookie, cookieUV).a;
#elif defined(_MAIN_SPOT_LIGHT)
float4 projPos = mul(_WorldToLight, float4(worldPos, 1.0));
float2 cookieUV = projPos.xy / projPos.w + 0.5;
return tex2D(_MainLightCookie, cookieUV).a;
#endif // POINT LIGHT cookie not supported
#endif
return 1;
}
// Matches Unity Vanila attenuation
half DistanceAttenuation(half3 distanceSqr, half4 distanceAttenuation)
{
// We use a shared distance attenuation for additional directional and puctual lights
// for directional lights attenuation will be 1
half quadFalloff = distanceAttenuation.x;
half denom = distanceSqr * quadFalloff + 1.0;
half lightAtten = 1.0 / denom;
// We need to smoothly fade attenuation to light range. We start fading linearly at 80% of light range
// Therefore:
// fadeDistance = (0.8 * 0.8 * lightRangeSq)
// smoothFactor = (lightRangeSqr - distanceSqr) / (lightRangeSqr - fadeDistance)
// We can rewrite that to fit a MAD by doing
// distanceSqr * (1.0 / (fadeDistanceSqr - lightRangeSqr)) + (-lightRangeSqr / (fadeDistanceSqr - lightRangeSqr)
// distanceSqr * distanceAttenuation.y + distanceAttenuation.z
half smoothFactor = saturate(distanceSqr * distanceAttenuation.y + distanceAttenuation.z);
return lightAtten * smoothFactor;
}
half SpotAttenuation(half3 spotDirection, half3 lightDirection, half4 spotAttenuation)
{
// Spot Attenuation with a linear falloff can be defined as
// (SdotL - cosOuterAngle) / (cosInnerAngle - cosOuterAngle)
// This can be rewritten as
// invAngleRange = 1.0 / (cosInnerAngle - cosOuterAngle)
// SdotL * invAngleRange + (-cosOuterAngle * invAngleRange)
// SdotL * spotAttenuation.x + spotAttenuation.y
// If we precompute the terms in a MAD instruction
half SdotL = dot(spotDirection, lightDirection);
return saturate(SdotL * spotAttenuation.x + spotAttenuation.y);
}
// Attenuation smoothly decreases to light range.
inline half ComputeLightAttenuation(LightInput lightInput, half3 normal, float3 worldPos, out half3 lightDirection)
{
float3 posToLightVec = lightInput.pos.xyz - worldPos * lightInput.pos.w;
float distanceSqr = max(dot(posToLightVec, posToLightVec), 0.001);
// normalized light dir
lightDirection = half3(posToLightVec * rsqrt(distanceSqr));
half lightAtten = DistanceAttenuation(distanceSqr, lightInput.distanceAttenuation);
lightAtten *= SpotAttenuation(lightInput.spotDirection.xyz, lightDirection, lightInput.spotAttenuation);
return lightAtten;
}
inline half ComputeMainLightAttenuation(LightInput lightInput, half3 normalWS, float3 positionWS, out half3 lightDirection)
{
#ifdef _MAIN_DIRECTIONAL_LIGHT
// Light pos holds normalized light dir
lightDirection = lightInput.pos;
half attenuation = 1.0;
#else
half attenuation = ComputeLightAttenuation(lightInput, normalWS, positionWS, lightDirection);
#endif
// Cookies and shadows are only computed for main light
attenuation *= CookieAttenuation(positionWS);
attenuation *= LIGHTWEIGHT_SHADOW_ATTENUATION(positionWS, normalWS, lightDirection);
return attenuation;
}
half3 VertexLighting(float3 positionWS, half3 normalWS)
{
half3 vertexLightColor = half3(0.0, 0.0, 0.0);
#if defined(_VERTEX_LIGHTS)
int vertexLightStart = _AdditionalLightCount.x;
int vertexLightEnd = min(_AdditionalLightCount.y, unity_LightIndicesOffsetAndCount.y);
for (int lightIter = vertexLightStart; lightIter < vertexLightEnd; ++lightIter)
{
LightInput light;
INITIALIZE_LIGHT(light, lightIter);
half3 lightDirection;
half atten = ComputeLightAttenuation(light, normalWS, positionWS, lightDirection);
half3 lightColor = light.color * atten;
vertexLightColor += LightingLambert(lightColor, lightDirection, normalWS);
}
#endif
return vertexLightColor;
}
half4 LightweightFragmentPBR(float3 positionWS, half3 normalWS, half3 viewDirectionWS, half3 indirectDiffuse, half3 vertexLighting, half3 albedo, half metallic, half3 specular, half smoothness, half occlusion, half3 emission, half alpha)
{
BRDFData brdfData;
InitializeBRDFData(albedo, metallic, specular, smoothness, alpha, brdfData);
half3 reflectVec = reflect(-viewDirectionWS, normalWS);
half roughness2 = brdfData.roughness * brdfData.roughness;
indirectDiffuse *= occlusion;
half3 indirectSpecular = GlossyEnvironment(reflectVec, brdfData.perceptualRoughness) * occlusion;
// PBS
half fresnelTerm = _Pow4(1.0 - saturate(dot(normalWS, viewDirectionWS)));
half3 color = LightweightEnvironmentBRDF(brdfData, indirectDiffuse, indirectSpecular, roughness2, fresnelTerm);
half3 lightDirectionWS;
LightInput light;
INITIALIZE_MAIN_LIGHT(light);
half lightAtten = ComputeMainLightAttenuation(light, normalWS, positionWS, lightDirectionWS);
half NdotL = saturate(dot(normalWS, lightDirectionWS));
half3 radiance = light.color * (lightAtten * NdotL);
color += LightweightBDRF(brdfData, roughness2, normalWS, lightDirectionWS, viewDirectionWS) * radiance;
color += vertexLighting * brdfData.diffuse;
#ifdef _ADDITIONAL_LIGHTS
int pixelLightCount = min(_AdditionalLightCount.x, unity_LightIndicesOffsetAndCount.y);
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
{
LightInput light;
INITIALIZE_LIGHT(light, lightIter);
half lightAtten = ComputeLightAttenuation(light, normalWS, positionWS, lightDirectionWS);
half NdotL = saturate(dot(normalWS, lightDirectionWS));
half3 radiance = light.color * (lightAtten * NdotL);
color += LightweightBDRF(brdfData, roughness2, normalWS, lightDirectionWS, viewDirectionWS) * radiance;
}
#endif
color += emission;
return half4(color, alpha);
}
half4 LightweightFragmentLambert(float3 positionWS, half3 normalWS, half3 viewDirectionWS, half fogFactor, half3 diffuseGI, half3 diffuse, half3 emission, half alpha)
{
half3 lightDirection;
half3 diffuseColor = diffuseGI;
LightInput mainLight;
INITIALIZE_MAIN_LIGHT(mainLight);
half lightAtten = ComputeMainLightAttenuation(mainLight, normalWS, positionWS, lightDirection);
half3 lightColor = mainLight.color * lightAtten;
diffuseColor += LightingLambert(lightColor, lightDirection, normalWS);
#ifdef _ADDITIONAL_LIGHTS
int pixelLightCount = min(_AdditionalLightCount.x, unity_LightIndicesOffsetAndCount.y);
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
{
LightInput lightData;
INITIALIZE_LIGHT(lightData, lightIter);
lightAtten = ComputeLightAttenuation(lightData, normalWS, positionWS, lightDirection);
lightColor = lightData.color * lightAtten;
diffuseColor += LightingLambert(lightColor, lightDirection, normalWS);
}
#endif // _ADDITIONAL_LIGHTS
half3 finalColor = diffuseColor * diffuse + emission;
// Computes Fog Factor per vextex
ApplyFog(finalColor, fogFactor);
half4 color = half4(finalColor, alpha);
return OUTPUT_COLOR(color);
}
half4 LightweightFragmentBlinnPhong(float3 positionWS, half3 normalWS, half3 viewDirectionWS, half fogFactor, half3 diffuseGI, half3 diffuse, half4 specularGloss, half shininess, half3 emission, half alpha)
{
half3 lightDirection;
half3 diffuseColor = diffuseGI;
half3 specularColor;
LightInput mainLight;
INITIALIZE_MAIN_LIGHT(mainLight);
half lightAtten = ComputeMainLightAttenuation(mainLight, normalWS, positionWS, lightDirection);
half3 lightColor = mainLight.color * lightAtten;
diffuseColor += LightingLambert(lightColor, lightDirection, normalWS);
specularColor = LightingSpecular(lightColor, lightDirection, normalWS, viewDirectionWS, specularGloss, shininess);
#ifdef _ADDITIONAL_LIGHTS
int pixelLightCount = min(_AdditionalLightCount.x, unity_LightIndicesOffsetAndCount.y);
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
{
LightInput lightData;
INITIALIZE_LIGHT(lightData, lightIter);
lightAtten = ComputeLightAttenuation(lightData, normalWS, positionWS, lightDirection);
lightColor = lightData.color * lightAtten;
diffuseColor += LightingLambert(lightColor, lightDirection, normalWS);
specularColor += LightingSpecular(lightColor, lightDirection, normalWS, viewDirectionWS, specularGloss, shininess);
}
#endif // _ADDITIONAL_LIGHTS
half3 finalColor = diffuseColor * diffuse + emission;
finalColor += specularColor;
// Computes Fog Factor per vextex
ApplyFog(finalColor, fogFactor);
half4 color = half4(finalColor, alpha);
return OUTPUT_COLOR(color);
}
#endif