// TODO CLEANUP and put in proper define above
// Also, note that we have lobe-indexed arrays,
// and vlayer indexed for the generic vlayer
// and vlayer indexed for the generic vlayer
//#define INTERFACE_TOP_IDX 0
//#define INTERFACE_TOP_IDX 0
//#define INTERFACE_BASE_IDX 1
// Use these to index vLayerEnergyCoeff[] !
return (HasFeatureFlag(bsdfData.materialFeatures, MATERIALFEATUREFLAGS_STACK_LIT_COAT));
}
float3 ComputeDiffuseColor(float3 baseColor, float metallic)
{
return baseColor * (1.0 - metallic);
}
float3 ComputeFresnel0(float3 baseColor, float metallic, float dielectricF0)
{
return lerp(dielectricF0.xxx, baseColor, metallic);
}
// Assume bsdfData.normalWS is init
void FillMaterialAnisotropy(float anisotropy, float3 tangentWS, float3 bitangentWS, inout BSDFData bsdfData)
{
float CalculateEnergyCompensationFromSpecularReflectivity(float specularReflectivity)
{
// Ref: Practical multiple scattering compensation for microfacet models.
// Ref: Practical multiple scattering compensation for microfacet models.
// We only apply the formulation for metals.
// For dielectrics, the change of reflectance is negligible.
// We deem the intensity difference of a couple of percent for high values of roughness
// Note that using this factor for all specular lighting assumes all
// Note that using this factor for all specular lighting assumes all
// Make it roughly usable with a lerp factor with - 1.0, see ApplyEnergyCompensationToSpecularLighting()
// Make it roughly usable with a lerp factor with - 1.0, see ApplyEnergyCompensationToSpecularLighting()
// The "lerp factor" will be fresnel0
float energyCompensation = 1.0 / specularReflectivity - 1.0;
return energyCompensation;
void ApplyDebugToSurfaceData(float3x3 worldToTangent, inout SurfaceData surfaceData)
{
#ifdef DEBUG_DISPLAY
// NOTE: THe _Debug* uniforms come from /HDRP/Debug/DebugDisplay.hlsl
// Override value if requested by user
// this can be use also in case of debug lighting mode like diffuse only
bool overrideAlbedo = _DebugLightingAlbedo.x != 0.0;
if (overrideSmoothness)
{
//NEWLITTODO
//float overrideSmoothnessValue = _DebugLightingSmoothness.y;
//surfaceData.perceptualSmoothness = overrideSmoothnessValue;
float overrideSmoothnessValue = _DebugLightingSmoothness.y;
surfaceData.perceptualSmoothnessA = overrideSmoothnessValue;
surfaceData.perceptualSmoothnessB = overrideSmoothnessValue;
surfaceData.coatPerceptualSmoothness = overrideSmoothnessValue;
}
if (overrideNormal)
surfaceData.coatIor, surfaceData.coatThickness, surfaceData.coatExtinction, bsdfData);
// vlayering:
// We can't calculate final roughnesses including anisotropy right away in this case: we will either do it
// one time at GetPreLightData or for each light depending on the configuration for accuracy of BSDF
// We can't calculate final roughnesses including anisotropy right away in this case: we will either do it
// one time at GetPreLightData or for each light depending on the configuration for accuracy of BSDF
// We have a coat top layer: change the base fresnel0 accordingdly:
// We have a coat top layer: change the base fresnel0 accordingdly:
bsdfData.fresnel0 = ConvertF0ForAirInterfaceToF0ForNewTopIor(bsdfData.fresnel0, bsdfData.coatIor);
// We just dont clamp the roughnesses for now, but after the ComputeAdding() which will use those:
{
// roughnessT and roughnessB are clamped, and are meant to be used with punctual and directional lights.
// perceptualRoughness is not clamped, and is meant to be used for IBL.
// TODO: add ui inputs, +tangent map for anisotropy;
// TODO: add ui inputs, +tangent map for anisotropy;
bsdfData.ambientOcclusion = surfaceData.ambientOcclusion;
ApplyDebugToBSDFData(bsdfData);
return bsdfData;
float3 iblR[TOTAL_NB_LOBES]; // Dominant specular direction, used for IBL in EvaluateBSDF_Env()
float iblPerceptualRoughness[TOTAL_NB_LOBES];
// IBL precalculation code modifies the perceptual roughnesses, so we need those too.
// For analytical lights, clamping is needed (epsilon instead of 0 roughness, which
// would be troublesome to use for perfectly smooth IBL reflections, and roughness
// For analytical lights, clamping is needed (epsilon instead of 0 roughness, which
// would be troublesome to use for perfectly smooth IBL reflections, and roughness
// is split by anisotropy, while IBL anisotropy is delt with a hack on the used iblR
// vector, with the non-anisotropic roughness).
// cf with Lit.hlsl: originally, it has a coat section with its own
// iblR, iblF, PartLambdaV: this is due to the fact that it was the only
// extra lobe, and simplified: we didn't want to pay the cost of an FGD fetch
// for it (hence the name iblF in Lit). Here, we will fold all data into
// for it (hence the name iblF in Lit). Here, we will fold all data into
// For clarity, we will dump the base layer lobes roughnesses used by analytical lights
// For clarity, we will dump the base layer lobes roughnesses used by analytical lights
// We don't reuse the BSDFData roughnessAT/AB/BT/BB because we might need the original
// values per light (ie not only once at GetPreLightData time) to recompute new roughnesses
// We don't reuse the BSDFData roughnessAT/AB/BT/BB because we might need the original
// values per light (ie not only once at GetPreLightData time) to recompute new roughnesses
// For consistency with nonperceptual anisotropic and clamped roughnessAT/AB/BT/BB
// For consistency with nonperceptual anisotropic and clamped roughnessAT/AB/BT/BB
// which are stored in BSDFData, coatRoughness (for analytical lights) will
// also be stored in BSDFData.
// (ComputeAdding changing roughness per light is what will make them change).
//
// This used to be strictly done in GetPreLightData, but since this is NOT useful
// for IBLs, if vlayering is enabled and we want the vlayer stats recomputation
// per analytical light, we must NOT do it in GetPreLightData (will be wasted) and
// for IBLs, if vlayering is enabled and we want the vlayer stats recomputation
// per analytical light, we must NOT do it in GetPreLightData (will be wasted) and
//
//
float coatIeta;
float vLayerPerceptualRoughness[NB_VLAYERS];
// We will duplicate one entry to simplify the IBL loop
// (In general it's either that or we add branches (if lobe from bottom interface or
// top inteface) in the loop and make sure the compiler [unroll] - should be automatic
// on a static loop - as then the compiler will remove these known branches as it unrolls.
// All our loops for lobes are static so either way it should unroll and remove either
// We will duplicate one entry to simplify the IBL loop
// (In general it's either that or we add branches (if lobe from bottom interface or
// top inteface) in the loop and make sure the compiler [unroll] - should be automatic
// on a static loop - as then the compiler will remove these known branches as it unrolls.
// All our loops for lobes are static so either way it should unroll and remove either
// PostEvaluateBSDF time, and for the vlayered case, fold compensation into FGD
// PostEvaluateBSDF time, and for the vlayered case, fold compensation into FGD
// terms during ComputeAdding (ie FGD becomes FGDinf) (but the approximation depends on f0,
// our FGD is scalar, not rgb, see GetEnergyCompensationFactor.)
float3 energyFactor[TOTAL_NB_LOBES];
float3 energyFactor[TOTAL_NB_LOBES];
//See VLAYERED_DIFFUSE_ENERGY_HACKED_TERM
float3 diffuseEnergy;
//-----------------------------------------------------------------------------
// About layered BSDF statistical lobe data calculations:
//
//
//
//
// use the angle of directions at the interface that generated the output lobe
// use the angle of directions at the interface that generated the output lobe
// -(Point B) By symmetry of refractions top/down -> bottom/up, lobe directional
// stats stay the same for lighting calculations (so use original top interface
// -(Point B) By symmetry of refractions top/down -> bottom/up, lobe directional
// stats stay the same for lighting calculations (so use original top interface
// -If we use energy coefficients for IBL, use FGD terms during ComputeAdding
// (FGDinf in fact, TODOENERGY) for all adding-equation operators. FGD is fetched
// during the algo, at the right angle.
// -If we use energy coefficients for IBL, use FGD terms during ComputeAdding
// (FGDinf in fact, TODOENERGY) for all adding-equation operators. FGD is fetched
// during the algo, at the right angle.
// correct is a (1-FGD) term at the top), ie, for everything below the first interface,
// but use the actual Fresnel term for that light for R12 at the start
// correct is a (1-FGD) term at the top), ie, for everything below the first interface,
// but use the actual Fresnel term for that light for R12 at the start
// If you recompute everything per light, FGD fetches per light might be expensive,
// so could use the FGD used for IBLs, angle used will be more or less incorrect
// If you recompute everything per light, FGD fetches per light might be expensive,
// so could use the FGD used for IBLs, angle used will be more or less incorrect
// -Right now the method uses Fresnel terms for everything.
// -Right now the method uses Fresnel terms for everything.
// of points A and B. In particular, IBL fetches are light sample (ie don't refract
// of points A and B. In particular, IBL fetches are light sample (ie don't refract
// doing the FGD fetches directly during ComputeAdding. Then the output energy terms
// doing the FGD fetches directly during ComputeAdding. Then the output energy terms
//
//
//
//
//
//
//
// If the energy coefficients are intended to be used solely in a split sum IBL context,
//
// If the energy coefficients are intended to be used solely in a split sum IBL context,
//
// If they are going to be used for analytical lights also, this gets a bit more tricky
// (see details below), as the first R12 need not be an average but can be the actual
//
// If they are going to be used for analytical lights also, this gets a bit more tricky
// (see details below), as the first R12 need not be an average but can be the actual
// The application of analytical lights seems more natural as you could use your full
// The application of analytical lights seems more natural as you could use your full
//
// (Also ComputeAdding in that case (for every analytical lights) can be done with
// LdotH ie in a half-vector reference frame for the adding calculations but still use
//
// (Also ComputeAdding in that case (for every analytical lights) can be done with
// LdotH ie in a half-vector reference frame for the adding calculations but still use
// If in ComputeAdding() you use FGD for reflection, you need to be aware that you are
// targeting more a split sum formulation for eg IBL, and the other part of the sum is
// integral(L) (or importance sampled L, ie integral(LD), the later is the one we use).
// This would mean using D_GGX() (for the equivalent of preLD) directly in analytical
// light evaluations instead of the full BSDF. However, test empirically, might still be
// better to use the full BSDF even then.
// (Using FGD means accounting an average omnidirectional-outgoing / unidirectional-incoming
// energy transfer, “directional albedo” form. But in analytical lights, dirac vanishes
// the first FGD integral, and the "LD" part will be very sparse and punctual, hence this
// If in ComputeAdding() you use FGD for reflection, you need to be aware that you are
// targeting more a split sum formulation for eg IBL, and the other part of the sum is
// integral(L) (or importance sampled L, ie integral(LD), the later is the one we use).
// This would mean using D_GGX() (for the equivalent of preLD) directly in analytical
// light evaluations instead of the full BSDF. However, test empirically, might still be
// better to use the full BSDF even then.
// (Using FGD means accounting an average omnidirectional-outgoing / unidirectional-incoming
// energy transfer, “directional albedo” form. But in analytical lights, dirac vanishes
// the first FGD integral, and the "LD" part will be very sparse and punctual, hence this
//
//
//
// However, if like done now ComputeAdding uses Fresnel terms directly, then IBLs
// need to fetch FGD using the Fresnel term chain (energy coefficients) as an F0
//
// However, if like done now ComputeAdding uses Fresnel terms directly, then IBLs
// need to fetch FGD using the Fresnel term chain (energy coefficients) as an F0
// (eg through fake refraction) would have computed when having reached the interface that
// generated that output lobe*
// The reason is that the FGD term would have been fetched at that point, and accounted
// (eg through fake refraction) would have computed when having reached the interface that
// generated that output lobe*
// The reason is that the FGD term would have been fetched at that point, and accounted
//
//
// Another point: since ComputeAdding( ) uses angles for Fresnel energy terms, if we
// recalculate per light, we must use a parametrization (reference frame) according to H
// and NOT N. This also means we are making different assumptions about the way the
// propagation operators work: eg see p9 the Symmetric Model: it is as if roughness is not
// "injected" in the direction of the macrosurface but in the H direction. Although
// different, empirical results show that it is as valid. Note however that again, this
// Another point: since ComputeAdding( ) uses angles for Fresnel energy terms, if we
// recalculate per light, we must use a parametrization (reference frame) according to H
// and NOT N. This also means we are making different assumptions about the way the
// propagation operators work: eg see p9 the Symmetric Model: it is as if roughness is not
// "injected" in the direction of the macrosurface but in the H direction. Although
// different, empirical results show that it is as valid. Note however that again, this
//
// Offspecular effects:
// Since the ComputeAdding() method doesn’t really track mean directions but assume symmetry in
// the incidence plane (perpendicular to the “up” vector of the parametrization - either N or H
// depending on the given cti param - cos theta incident), only elevation angles are used, but
// output lobe directions (by symmetry of reflection and symmetry of transmission top-to-bottom
// Offspecular effects:
//
// Since the ComputeAdding() method doesn’t really track mean directions but assume symmetry in
// the incidence plane (perpendicular to the “up” vector of the parametrization - either N or H
// depending on the given cti param - cos theta incident), only elevation angles are used, but
// output lobe directions (by symmetry of reflection and symmetry of transmission top-to-bottom
// and thus do not impose a deviation on the w_i_fake value we need to conceptually use when
// instantiating a BSDF from our statistical representation of a lobe (so we just need to use
// and thus do not impose a deviation on the w_i_fake value we need to conceptually use when
// instantiating a BSDF from our statistical representation of a lobe (so we just need to use
//
// Offspecular effects are also ignored in the computations (which would break symmetry of
//
// Offspecular effects are also ignored in the computations (which would break symmetry of
// interfaces of *different* roughnesses), but, in the end, it is assumed (and can be seen as an
// approximation to correct a bit for that) that the output lobes increase of roughness should
// indeed tilt the resulting instantiated BSDF lobe a bit toward the normal (ie an offspecular
// tilt still happens but after and based on the whole layered stack stats that have been
// interfaces of *different* roughnesses), but, in the end, it is assumed (and can be seen as an
// approximation to correct a bit for that) that the output lobes increase of roughness should
// indeed tilt the resulting instantiated BSDF lobe a bit toward the normal (ie an offspecular
// tilt still happens but after and based on the whole layered stack stats that have been
//
// Again, since we don’t change w_i when instantiating an analytic BSDF, the change in roughness
// will incur that additional offspecular deviation naturally.
// For IBLs however, we take the resulting output (vlayer) roughness and calculate a correction
// to fetch through the dominant (central direction of the lobe) through GetSpecularDominantDir( )
// as usual, but using the refracted angle for the bottom interface because that is what specifies
//
// Again, since we don’t change w_i when instantiating an analytic BSDF, the change in roughness
// will incur that additional offspecular deviation naturally.
// For IBLs however, we take the resulting output (vlayer) roughness and calculate a correction
// to fetch through the dominant (central direction of the lobe) through GetSpecularDominantDir( )
// as usual, but using the refracted angle for the bottom interface because that is what specifies
//
// (Note also that offspecular effects are also outside the plane of reflection, as the later is
// defined by coplanar L, N and V while the tilt of the lobe is towards N. This adds to the
//
// (Note also that offspecular effects are also outside the plane of reflection, as the later is
// defined by coplanar L, N and V while the tilt of the lobe is towards N. This adds to the
//
//
// EnergyCompensation: This term can no longer be used alone in our vlayered BSDF framework as it
// was applied only one time indiscriminately at PostEvaluateBSDF( ) on the specular lighting which
// would be wrong in our case, since the correction terms depend on the interface the lobe
// corresponds to and compensation must happen at each FGD use in ComputeAdding. However, our
// framework is exactly designed to handle that problem, in that if we calculate and apply proper
// energy coefficient terms (should be calculated from FGDinf) and modulate each specular calculations
// EnergyCompensation: This term can no longer be used alone in our vlayered BSDF framework as it
// was applied only one time indiscriminately at PostEvaluateBSDF( ) on the specular lighting which
// would be wrong in our case, since the correction terms depend on the interface the lobe
// corresponds to and compensation must happen at each FGD use in ComputeAdding. However, our
// framework is exactly designed to handle that problem, in that if we calculate and apply proper
// energy coefficient terms (should be calculated from FGDinf) and modulate each specular calculations
// This creates another performance option: when in VLAYERED_RECOMPUTE_PERLIGHT mode, we
// don’t recompute for IBLs, but the coefficients for energy compensation would need to get FGD,
// and will require FGD fetches for each analytical light. (ie ComputeAdding( ) ideally should
// always do calculations with FGD and do the fetches, so that even in GetPreLightData, nothing
// would be done there). For now, and for performance reasons, we don’t provide the option.
//
// However, when VLAYERED_RECOMPUTE_PERLIGHT is not used, we actually get usable terms that we
// will apply to the specular lighting, but these are different, we have one per real interface
// This creates another performance option: when in VLAYERED_RECOMPUTE_PERLIGHT mode, we
// don’t recompute for IBLs, but the coefficients for energy compensation would need to get FGD,
// and will require FGD fetches for each analytical light. (ie ComputeAdding( ) ideally should
// always do calculations with FGD and do the fetches, so that even in GetPreLightData, nothing
// would be done there). For now, and for performance reasons, we don’t provide the option.
//
// However, when VLAYERED_RECOMPUTE_PERLIGHT is not used, we actually get usable terms that we
// will apply to the specular lighting, but these are different, we have one per real interface
// (so 2 vs the 3 “virtual” layer structure here).
// (FGDinf can be obtained from our FGD)
//
///Helper function that parses the BSDFData object to generate the current layer's
// statistics.
//
//
// T12 should be multiplied by TIR.
// T12 should be multiplied by TIR.
//
//
void ComputeStatistics(in float cti, in int i, in BSDFData bsdfData,
out float ctt,
out float3 R12, out float3 T12, out float3 R21, out float3 T21,
//
out float s_r21, out float s_t21, out float j21)
out float s_r21, out float s_t21, out float j21)
{
// Case of the dielectric coating
float sti = sqrt(1.0 - Sq(cti));
float stt = sti / n12;
if(stt <= 1.0f) {
// Hack: as roughness -> 1, remove the effect of changing angle also note: we never track means per se
// because of symmetry, we have no azimuth, and don't consider offspecular effect as well as never
// Hack: as roughness -> 1, remove the effect of changing angle also note: we never track means per se
// because of symmetry, we have no azimuth, and don't consider offspecular effect as well as never
// We just track cosines of angles for energy transfer calculations (should do with FGD but depends,
// We just track cosines of angles for energy transfer calculations (should do with FGD but depends,
// see comments above).
const float alpha = bsdfData.coatRoughness;
const float scale = clamp((1.0-alpha)*(sqrt(1.0-alpha) + alpha), 0.0, 1.0);
} else {
// TER, flip sign: directions either reflected or transmitted always leave
// TER, flip sign: directions either reflected or transmitted always leave
// the surface. So here we have ctt instead of cti, we reverse dir by flipping sign.
// Not accounted for though check implications of ctt = -1.0
// TODO
//
// HACK: we will not propagate all needed last values, as we have 4,
// but the adding cycle for the last layer can be shortcircuited for
// the last lobes we need without computing the whole state of the
// current stack (ie the i0 and 0i terms).
// the last lobes we need without computing the whole state of the
// current stack (ie the i0 and 0i terms).
//
// We're only interested in _s_r0m and m_R0i.
s_r12 = 0.0;
// Variables for the adding step
float3 R12, T12, R21, T21;
s_r12=0.0;
s_r12=0.0;
float s_r21=0.0, s_t12=0.0, s_t21=0.0, j12=1.0, j21=1.0, ctt;
// Layer specific evaluation of the transmittance, reflectance, variance
float3 denom = (float3(1.0, 1.0, 1.0) - Ri0*R12); //i = new layer, 0 = cumulative top (llab3.1 to 3.4)
float3 m_R0i = (mean(denom) <= 0.0f)? float3(0.0, 0.0, 0.0) : (T0i*R12*Ti0) / denom; //(llab3.1)
float3 m_Ri0 = (mean(denom) <= 0.0f)? float3(0.0, 0.0, 0.0) : (T21*Ri0*T12) / denom; //(llab3.2)
float3 m_Rr = (mean(denom) <= 0.0f)? float3(0.0, 0.0, 0.0) : (Ri0*R12) / denom;
float3 m_Rr = (mean(denom) <= 0.0f)? float3(0.0, 0.0, 0.0) : (Ri0*R12) / denom;
float m_r0i = mean(m_R0i);
float m_ri0 = mean(m_Ri0);
m_rr = mean(m_Rr);
// Update mean
cti = ctt;
// We need to escape this update on the last vlayer iteration,
// as we will use a hack to compute all needed bottom layer
// We need to escape this update on the last vlayer iteration,
// as we will use a hack to compute all needed bottom layer
if( i < (NB_VLAYERS-1) )
if( i < (NB_VLAYERS-1) )
{
// Update variance
s_r0i = _s_r0i;
// Works because we're the last "layer" and all variables touched
// above are in a state where these calculations will be valid:
//
// We have 6 roughnesses to process;
// We have 6 roughnesses to process;
// We need both bottom lobes
// We need both bottom lobes
// Then we need anisotropic roughness updates again for the 2
// Then we need anisotropic roughness updates again for the 2
// bottom lobes, for analytical lights.
//
// TODO: VLAYERED_RECOMPUTE_PERLIGHT and calledPerLight bool
// (note that vLayer*[0] and vLayer*[2] contains useful data,
// (note that vLayer*[0] and vLayer*[2] contains useful data,
//
//
//preLightData.iblPerceptualRoughness[COAT_LOBE_IDX] = preLightData.vLayerPerceptualRoughness[TOP_VLAYER_IDX];
#ifdef VLAYERED_RECOMPUTE_PERLIGHT
#endif
bool haveAnisotropy = HasFeatureFlag(bsdfData.materialFeatures, MATERIALFEATUREFLAGS_STACK_LIT_ANISOTROPY);
// calledPerLight and all of the bools above are static time known.
// calledPerLight and all of the bools above are static time known.
// and our calling context here is per light, we shouldn't deal with the perceptual roughnesses
// for IBLs, nor with their anisotropy parameter recalculation. So we only deal with the roughness
// and our calling context here is per light, we shouldn't deal with the perceptual roughnesses
// for IBLs, nor with their anisotropy parameter recalculation. So we only deal with the roughness
// Otherwise, depending on if we have anisotropy or not, we might still have to deal with
// Otherwise, depending on if we have anisotropy or not, we might still have to deal with
// That hack adds complexity because IBLs they can't use the T and B roughnesses but at the
// same time we can't just update their scalar roughness because then it will only give them more
// roughness in the anisotropic direction.
// That hack adds complexity because IBLs they can't use the T and B roughnesses but at the
// same time we can't just update their scalar roughness because then it will only give them more
// roughness in the anisotropic direction.
// There's no anisotropy and we haven't clamped the roughness in the T and B fields, so
// that we can use directly bsdfData.roughness?T == bsdfData.roughness?B
// == PerceptualRoughnessToRoughness(bsdfData.perceptualRoughnessA)) :
// There's no anisotropy and we haven't clamped the roughness in the T and B fields, so
// that we can use directly bsdfData.roughness?T == bsdfData.roughness?B
// == PerceptualRoughnessToRoughness(bsdfData.perceptualRoughnessA)) :
//s_r12 = RoughnessToLinearVariance(PerceptualRoughnessToRoughness(bsdfData.perceptualRoughnessA));
s_r12 = RoughnessToLinearVariance(bsdfData.roughnessAT);
_s_r0m = s_ti0 + j0i*(s_t0i + s_r12 + m_rr*(s_r12+s_ri0));
if( !calledPerLight && haveAnisotropy)
{
// We're in GetPreLightData context so we need to deal with IBL precalc, and
// regardless of if we had the VLAYERED_RECOMPUTE_PERLIGHT option or not, we
// still need to compute the full anistropic modification of variances.
// We're in GetPreLightData context so we need to deal with IBL precalc, and
// regardless of if we had the VLAYERED_RECOMPUTE_PERLIGHT option or not, we
// still need to compute the full anistropic modification of variances.
// We proceed as follow: Convert T & B roughnesses to variance, propagate the effect of layers,
// infer back a new anisotropy parameter and roughness from them:
_s_r0m = s_ti0 + j0i*(s_t0i + s_r12 + m_rr*(s_r12+s_ri0));
float roughnessB = LinearVarianceToRoughness(_s_r0m);
//preLightData.iblAnisotropy[0] = RoughnessToAnisotropy(roughnessT, roughnessB );
//ConvertRoughnessToAnisotropy(roughnessT, roughnessB, preLightData.iblAnisotropy[0] );
if( !perLightOption )
if( !perLightOption )
// LOBEA T and B part:
// LOBEA T and B part:
// We do the same for LOBEB:
// We do the same for LOBEB:
// -------------------------
// LOBEB roughness for analytical lights (T part)
_s_r0m = s_ti0 + j0i*(s_t0i + s_r12 + m_rr*(s_r12+s_ri0));
roughnessB = LinearVarianceToRoughness(_s_r0m);
//preLightData.iblAnisotropy[1] = RoughnessToAnisotropy(roughnessT, roughnessB );
// ConvertRoughnessToAnisotropy(roughnessT, roughnessB, preLightData.iblAnisotropy[1] );
if( !perLightOption )
if( !perLightOption )
// LOBEB T and B part:
// LOBEB T and B part:
preLightData.layeredRoughnessT[1] = ClampRoughnessForAnalyticalLights(roughnessT);
preLightData.layeredRoughnessB[1] = ClampRoughnessForAnalyticalLights(roughnessB);
}
preLightData.NdotV = dot(N, V);
float NdotV = ClampNdotV(preLightData.NdotV);
// For eval IBL lights, we need:
// For eval IBL lights, we need:
// iblPerceptualRoughness for FGD, mip, etc
// iblPerceptualRoughness for FGD, mip, etc
// energyCompensation (for all light, apply everytime since with layering it becomes
// energyCompensation (for all light, apply everytime since with layering it becomes
// We also need for analytical lights:
// We also need for analytical lights:
// coatRoughness, roughnessAT/AB/BT/BB (anisotropic, all are nonperceptual and *clamped*)
// coatRoughness, roughnessAT/AB/BT/BB (anisotropic, all are nonperceptual and *clamped*)
// The later are done here only if we're not using VLAYERED_RECOMPUTE_PERLIGHT.
// The later are done here only if we're not using VLAYERED_RECOMPUTE_PERLIGHT.
// TODO this can now be refactored instead of having mostly duped code down here,
// TODO this can now be refactored instead of having mostly duped code down here,
//
// Use loops and special case with IsVLayeredEnabled(bsdfData) which is statically known.
// First thing we need is compute the energy coefficients and new roughnesses.
// Even if configured to do it also per analytical light, we need it for IBLs too.
ComputeAdding(NdotV, bsdfData, preLightData, false);
// After ComputeAdding, these are done for all lobes:
// After ComputeAdding, these are done for all lobes:
// preLightData.iblPerceptualRoughness[]
// preLightData.iblPerceptualRoughness[]
// If we're not using VLAYERED_RECOMPUTE_PERLIGHT we also have calculated
// If we're not using VLAYERED_RECOMPUTE_PERLIGHT we also have calculated
// preLightData.layeredRoughnessT and B[],
// preLightData.layeredCoatRoughness
// Otherwise, the calculation of these is done for each light
// Handle IBL pre calculated data + GGX multiscattering energy loss compensation term
// Here, we will fetch our actual FGD terms, see ComputeAdding for details: the F0 params
// will be replaced by our energy coefficients. Note that the way to do it depends on the
// will be replaced by our energy coefficients. Note that the way to do it depends on the
// at the top interface, for the FGD terms (in fact, for all angle dependent BSDF
// at the top interface, for the FGD terms (in fact, for all angle dependent BSDF
// because our ComputeAdding formulation is with "energy" coefficients calculated with a
// because our ComputeAdding formulation is with "energy" coefficients calculated with a
baseLayerNdotV = sqrt(1 + Sq(preLightData.coatIeta)*(Sq(NdotV) - 1));
baseLayerNdotV = sqrt(1 + Sq(preLightData.coatIeta)*(Sq(NdotV) - 1));
GetPreIntegratedFGDGGXAndDisneyDiffuse(NdotV,
preLightData.iblPerceptualRoughness[COAT_LOBE_IDX],
preLightData.vLayerEnergyCoeff[TOP_VLAYER_IDX],
preLightData.specularFGD[COAT_LOBE_IDX],
diffuseFGDTmp,
GetPreIntegratedFGDGGXAndDisneyDiffuse(NdotV,
preLightData.iblPerceptualRoughness[COAT_LOBE_IDX],
preLightData.vLayerEnergyCoeff[TOP_VLAYER_IDX],
preLightData.specularFGD[COAT_LOBE_IDX],
diffuseFGDTmp,
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX],
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX],
preLightData.specularFGD[BASE_LOBEA_IDX],
diffuseFGD[0],
preLightData.specularFGD[BASE_LOBEA_IDX],
diffuseFGD[0],
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEB_IDX],
preLightData.vLayerEnergyCoeff[BOTTOM_VLAYER_IDX],
preLightData.specularFGD[BASE_LOBEB_IDX],
diffuseFGD[1],
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEB_IDX],
preLightData.vLayerEnergyCoeff[BOTTOM_VLAYER_IDX],
preLightData.specularFGD[BASE_LOBEB_IDX],
diffuseFGD[1],
specularReflectivity[BASE_LOBEB_IDX]);
iblR[0] = reflect(-V, iblN[0]);
// Correction of reflected direction for better handling of rough material
// Notice again that the roughness and iblR properly use the output lobe statistics, but baseLayerNdotV
// is used for the offspecular correction because the true original offspecular tilt is parametrized by
// is used for the offspecular correction because the true original offspecular tilt is parametrized by
// the angle at the base layer and the correction itself is influenced by that. See comments above.
preLightData.iblR[COAT_LOBE_IDX] = GetSpecularDominantDir(N, iblR[COAT_LOBE_IDX], preLightData.iblPerceptualRoughness[COAT_LOBE_IDX], NdotV);
preLightData.iblR[BASE_LOBEA_IDX] = GetSpecularDominantDir(N, iblR[BASE_LOBEA_IDX], preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX], baseLayerNdotV);
// TODOENERGY:
// This is actually changing FGD to FGDinf in the vlayering framework but this needs to be folded in the energy calculations
// This is actually changing FGD to FGDinf in the vlayering framework but this needs to be folded in the energy calculations
// See TODOENERGY [eg: (a1*ef)(1-(a2*ef)) != ef (a1)(1-a2) ]
// See TODOENERGY [eg: (a1*ef)(1-(a2*ef)) != ef (a1)(1-a2) ]
float specularReflectivityBase = lerp(specularReflectivity[BASE_LOBEA_IDX], specularReflectivity[BASE_LOBEB_IDX], bsdfData.lobeMix);
#else
//preLightData.energyCompensation[COAT_LOBE_IDX] =
//preLightData.energyCompensation[BASE_LOBEA_IDX] =
//preLightData.energyCompensation[COAT_LOBE_IDX] =
//preLightData.energyCompensation[BASE_LOBEA_IDX] =
preLightData.energyFactor[BASE_LOBEA_IDX] =
preLightData.energyFactor[BASE_LOBEB_IDX] =
preLightData.energyFactor[BASE_LOBEA_IDX] =
preLightData.energyFactor[BASE_LOBEB_IDX] =
preLightData.energyFactor[COAT_LOBE_IDX] = 1.0;
#endif
// NO VLAYERING:
// NO VLAYERING:
// To make BSDF( ) evaluation more generic, even if we're not vlayered,
// we will use these:
// Handle IBL pre calculated data + GGX multiscattering energy loss compensation term
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV, // just NdotV here...
preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX],
bsdfData.fresnel0,
preLightData.specularFGD[BASE_LOBEA_IDX],
diffuseFGD[0],
preLightData.iblPerceptualRoughness[BASE_LOBEA_IDX],
bsdfData.fresnel0,
preLightData.specularFGD[BASE_LOBEA_IDX],
diffuseFGD[0],
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEB_IDX],
bsdfData.fresnel0,
preLightData.specularFGD[BASE_LOBEB_IDX],
diffuseFGD[1],
GetPreIntegratedFGDGGXAndDisneyDiffuse(baseLayerNdotV,
preLightData.iblPerceptualRoughness[BASE_LOBEB_IDX],
bsdfData.fresnel0,
preLightData.specularFGD[BASE_LOBEB_IDX],
diffuseFGD[1],
specularReflectivity[BASE_LOBEB_IDX]);
preLightData.iblR[1] = GetSpecularDominantDir(N, iblR[1], preLightData.iblPerceptualRoughness[1], NdotV);
#ifdef LIT_USE_GGX_ENERGY_COMPENSATION
// Here, since this compensation term is already an average applied to a sum
// Here, since this compensation term is already an average applied to a sum
// When in vlayering, the same split approximation idea is embedded in the whole aggregate statistical
// When in vlayering, the same split approximation idea is embedded in the whole aggregate statistical
// formulation. ie Compensation corresponds to using FGDinf instead of FGD.
float specR = lerp(specularReflectivity[0], specularReflectivity[1], bsdfData.lobeMix);
//preLightData.energyCompensation[0] = CalculateEnergyCompensationFromSpecularReflectivity(specR);
// This function require the 3 structure surfaceData, builtinData, bsdfData because it may require both the engine side data, and data that will not be store inside the gbuffer.
float3 GetBakedDiffuseLighting(SurfaceData surfaceData, BuiltinData builtinData, BSDFData bsdfData, PreLightData preLightData)
{
//NEWLITTODO
// TODO: Handle SSS
#ifdef DEBUG_DISPLAY
if (_DebugLightingMode == DEBUGLIGHTINGMODE_LUX_METER)
}
#endif
//NEWLITTODO
// Premultiply bake diffuse lighting information with DisneyDiffuse pre-integration
//return builtinData.bakeDiffuseLighting * preLightData.diffuseFGD * surfaceData.ambientOcclusion * bsdfData.diffuseColor + builtinData.emissiveColor;
return builtinData.bakeDiffuseLighting * bsdfData.diffuseColor; //...todo, just to return something for now, .bakeDiffuseLighting is bogus for now anyway.
// Premultiply bake diffuse lighting information
return builtinData.bakeDiffuseLighting * surfaceData.ambientOcclusion * bsdfData.diffuseColor + builtinData.emissiveColor;
}
// TODO: Refraction
// There is no coat handling in Lit for refractions.
// Here handle one lobe instead of all the others basically, or we could want it all.
// Could use proper transmission term T0i when vlayered and a total refraction lobe
// Could use proper transmission term T0i when vlayered and a total refraction lobe
// variance (need to get it in ComputeAdding, TODOTODO)
#if !HAS_REFRACTION
// -Fudge the sampling direction to dampen boundary artefacts.
// -Do early discard for planar reflections.
// -Fetch samples of preintegrated environment lighting
// -Fetch samples of preintegrated environment lighting
// -Use the BSDF preintegration terms we pre-fetched in preLightData
// -Use the BSDF preintegration terms we pre-fetched in preLightData
// (second part of the split-sum approx.,
// and common to all Env. Lights. using the same BSDF and
// we only have GGX thus only one FGD map for now)
// TODOENERGY: should be done in ComputeAdding with FGD formulation for IBL.
// Note that when we're not vlayered, we apply it not at each light sample but at the end,
// at PostEvaluateBSDF.
// Incorrect, but just for now:
// Incorrect, but just for now:
//L = ApplyEnergyCompensationToSpecularLighting(L, preLightData.fresnel0[i], preLightData.energyCompensation[i]);
L *= preLightData.energyFactor[i];
}
PreLightData preLightData, BSDFData bsdfData, BakeLightingData bakeLightingData, AggregateLighting lighting,
out float3 diffuseLighting, out float3 specularLighting)
{
// TODO: AO, SO, SSS, Refraction
float3 bakeDiffuseLighting = bakeLightingData.bakeDiffuseLighting;
AmbientOcclusionFactor aoFactor;
// Use GTAOMultiBounce approximation for ambient occlusion (allow to get a tint from the baseColor)
GetScreenSpaceAmbientOcclusionMultibounce(posInput.positionSS, preLightData.NdotV, lerp(bsdfData.perceptualRoughnessA, bsdfData.perceptualRoughnessB, bsdfData.lobeMix), bsdfData.ambientOcclusion, 1.0, bsdfData.diffuseColor, bsdfData.fresnel0, aoFactor);
// Add indirect diffuse + emissive (if any) - Ambient occlusion is multiply by emissive which is wrong but not a big deal
bakeDiffuseLighting *= aoFactor.indirectAmbientOcclusion;
lighting.direct.diffuse *= aoFactor.directAmbientOcclusion;
diffuseLighting = bsdfData.diffuseColor * lighting.direct.diffuse + bakeLightingData.bakeDiffuseLighting;
diffuseLighting = bsdfData.diffuseColor * lighting.direct.diffuse + bakeDiffuseLighting;
if( !IsVLayeredEnabled(bsdfData) )
if (!IsVLayeredEnabled(bsdfData))
//specularLighting = ApplyEnergyCompensationToSpecularLighting(specularLighting, bsdfData.fresnel0, preLightData.energyCompensation[0]);
#ifdef DEBUG_DISPLAY
break;
case DEBUGLIGHTINGMODE_INDIRECT_DIFFUSE_OCCLUSION:
// diffuseLighting = aoFactor.indirectAmbientOcclusion;
diffuseLighting = aoFactor.indirectAmbientOcclusion;
break;
case DEBUGLIGHTINGMODE_INDIRECT_SPECULAR_OCCLUSION:
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