Page MenuHome
Differential D17044 Diff 59641 intern/cycles/kernel/closure/bsdf_microfacet.h

Changeset View

Standalone View

View Options

intern/cycles/kernel/closure/bsdf_microfacet.h

Show All 10 Lines
#include "kernel/closure/bsdf_util.h" #include "kernel/closure/bsdf_util.h"
#include "kernel/sample/pattern.h" #include "kernel/sample/pattern.h"
#include "kernel/util/lookup_table.h" #include "kernel/util/lookup_table.h"
CCL_NAMESPACE_BEGIN CCL_NAMESPACE_BEGIN
enum MicrofacetType {
BECKMANN,
GGX,
};
typedef struct MicrofacetExtra { typedef struct MicrofacetExtra {
Spectrum color, cspec0; Spectrum color, cspec0;
Spectrum fresnel_color; Spectrum fresnel_color;
float clearcoat; float clearcoat;
} MicrofacetExtra; } MicrofacetExtra;
typedef struct MicrofacetBsdf { typedef struct MicrofacetBsdf {
SHADER_CLOSURE_BASE; SHADER_CLOSURE_BASE;
▲ Show 20 Lines • Show All 143 Lines • ▼ Show 20 Lines else {
randv = 2.0f * (0.5f - randv); randv = 2.0f * (0.5f - randv);
} }
const float z = (randv * (randv * (randv * 0.27385f - 0.73369f) + 0.46341f)) / const float z = (randv * (randv * (randv * 0.27385f - 0.73369f) + 0.46341f)) /
(randv * (randv * (randv * 0.093073f + 0.309420f) - 1.000000f) + 0.597999f); (randv * (randv * (randv * 0.093073f + 0.309420f) - 1.000000f) + 0.597999f);
*slope_y = S * z * safe_sqrtf(1.0f + (*slope_x) * (*slope_x)); *slope_y = S * z * safe_sqrtf(1.0f + (*slope_x) * (*slope_x));
} }
template<MicrofacetType m_type>
ccl_device_forceinline float3 microfacet_sample_stretched(KernelGlobals kg, ccl_device_forceinline float3 microfacet_sample_stretched(KernelGlobals kg,
const float3 wi, const float3 wi,
const float alpha_x, const float alpha_x,
const float alpha_y, const float alpha_y,
const float randu, const float randu,
const float randv, const float randv,
bool beckmann,
ccl_private float *G1i) ccl_private float *G1i)
{ {
/* 1. stretch wi */ /* 1. stretch wi */
float3 wi_ = make_float3(alpha_x * wi.x, alpha_y * wi.y, wi.z); float3 wi_ = make_float3(alpha_x * wi.x, alpha_y * wi.y, wi.z);
wi_ = normalize(wi_); wi_ = normalize(wi_);
/* Compute polar coordinates of wi_. */ /* Compute polar coordinates of wi_. */
float costheta_ = 1.0f; float costheta_ = 1.0f;
float sintheta_ = 0.0f; float sintheta_ = 0.0f;
float cosphi_ = 1.0f; float cosphi_ = 1.0f;
float sinphi_ = 0.0f; float sinphi_ = 0.0f;
if (wi_.z < 0.99999f) { if (wi_.z < 0.99999f) {
costheta_ = wi_.z; costheta_ = wi_.z;
sintheta_ = safe_sqrtf(1.0f - costheta_ * costheta_); sintheta_ = safe_sqrtf(1.0f - costheta_ * costheta_);
float invlen = 1.0f / sintheta_; float invlen = 1.0f / sintheta_;
cosphi_ = wi_.x * invlen; cosphi_ = wi_.x * invlen;
sinphi_ = wi_.y * invlen; sinphi_ = wi_.y * invlen;
} }
/* 2. sample P22_{wi}(x_slope, y_slope, 1, 1) */ /* 2. sample P22_{wi}(x_slope, y_slope, 1, 1) */
float slope_x, slope_y; float slope_x, slope_y;
if (beckmann) { if constexpr (m_type == MicrofacetType::BECKMANN) {
microfacet_beckmann_sample_slopes( microfacet_beckmann_sample_slopes(
kg, costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i); kg, costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i);
} }
else { else {
microfacet_ggx_sample_slopes(costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i); microfacet_ggx_sample_slopes(costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i);
} }
/* 3. rotate */ /* 3. rotate */
▲ Show 20 Lines • Show All 45 Lines • ▼ Show 20 Lines if (alpha2 >= 1.0f) {
return M_1_PI_F; return M_1_PI_F;
} }
const float t = 1.0f + (alpha2 - 1.0f) * cos_NH * cos_NH; const float t = 1.0f + (alpha2 - 1.0f) * cos_NH * cos_NH;
return (alpha2 - 1.0f) / (M_PI_F * logf(alpha2) * t); return (alpha2 - 1.0f) / (M_PI_F * logf(alpha2) * t);
} }
/* Monodirectional shadowing-masking term. */ /* Monodirectional shadowing-masking term. */
template<bool beckmann> ccl_device_inline float bsdf_G1_from_sqr_alpha_tan_n(float sqr_alpha_tan_n) template<MicrofacetType m_type>
ccl_device_inline float bsdf_G1_from_sqr_alpha_tan_n(float sqr_alpha_tan_n)
{ {
if (!beckmann) { /* GGX. */ if constexpr (m_type == MicrofacetType::GGX) {
return 2.0f / (1.0f + sqrtf(1.0f + sqr_alpha_tan_n)); return 2.0f / (1.0f + sqrtf(1.0f + sqr_alpha_tan_n));
} }
/* m_type == MicrofacetType::BECKMANN */
const float a = inversesqrtf(sqr_alpha_tan_n); const float a = inversesqrtf(sqr_alpha_tan_n);
return (a > 1.6f) ? 1.0f : ((2.181f * a + 3.535f) * a) / ((2.577f * a + 2.276f) * a + 1.0f); return (a > 1.6f) ? 1.0f : ((2.181f * a + 3.535f) * a) / ((2.577f * a + 2.276f) * a + 1.0f);
} }
template<bool beckmann> ccl_device_inline float bsdf_G1(float alpha2, float cos_N) template<MicrofacetType m_type> ccl_device_inline float bsdf_G1(float alpha2, float cos_N)
{ {
return bsdf_G1_from_sqr_alpha_tan_n<beckmann>(alpha2 * return bsdf_G1_from_sqr_alpha_tan_n<m_type>(alpha2 * fmaxf(1.0f / (cos_N * cos_N) - 1.0f, 0.0f));
fmaxf(1.0f / (cos_N * cos_N) - 1.0f, 0.0f));
} }
template<bool beckmann> template<MicrofacetType m_type>
ccl_device_inline float bsdf_aniso_G1(float alpha_x, float alpha_y, float3 V) ccl_device_inline float bsdf_aniso_G1(float alpha_x, float alpha_y, float3 V)
{ {
return bsdf_G1_from_sqr_alpha_tan_n<beckmann>((sqr(alpha_x * V.x) + sqr(alpha_y * V.y)) / return bsdf_G1_from_sqr_alpha_tan_n<m_type>((sqr(alpha_x * V.x) + sqr(alpha_y * V.y)) /
sqr(V.z)); sqr(V.z));
} }
/* Smith's separable shadowing-masking term. */ /* Smith's separable shadowing-masking term. */
template<bool beckmann> ccl_device_inline float bsdf_G(float alpha2, float cos_NI, float cos_NO) template<MicrofacetType m_type>
ccl_device_inline float bsdf_G(float alpha2, float cos_NI, float cos_NO)
{ {
return bsdf_G1<beckmann>(alpha2, cos_NI) * bsdf_G1<beckmann>(alpha2, cos_NO); return bsdf_G1<m_type>(alpha2, cos_NI) * bsdf_G1<m_type>(alpha2, cos_NO);
} }
/* Normal distribution function. */ /* Normal distribution function. */
template<bool beckmann> ccl_device_inline float bsdf_D(float alpha2, float cos_NH) template<MicrofacetType m_type> ccl_device_inline float bsdf_D(float alpha2, float cos_NH)
{ {
const float cos_NH2 = sqr(cos_NH); const float cos_NH2 = sqr(cos_NH);
return beckmann ? expf((1.0f - 1.0f / cos_NH2) / alpha2) / (M_PI_F * alpha2 * sqr(cos_NH2)) : if constexpr (m_type == MicrofacetType::BECKMANN) {
alpha2 / (M_PI_F * sqr(1.0f + (alpha2 - 1.0f) * cos_NH2)); return expf((1.0f - 1.0f / cos_NH2) / alpha2) / (M_PI_F * alpha2 * sqr(cos_NH2));
}
/* m_type == MicrofacetType::GGX */
return alpha2 / (M_PI_F * sqr(1.0f + (alpha2 - 1.0f) * cos_NH2));
} }
template<bool beckmann> template<MicrofacetType m_type>
ccl_device_inline float bsdf_aniso_D(float alpha_x, float alpha_y, float3 H) ccl_device_inline float bsdf_aniso_D(float alpha_x, float alpha_y, float3 H)
{ {
H /= make_float3(alpha_x, alpha_y, 1.0f); H /= make_float3(alpha_x, alpha_y, 1.0f);
const float cos_NH2 = sqr(H.z); const float cos_NH2 = sqr(H.z);
const float alpha2 = alpha_x * alpha_y; const float alpha2 = alpha_x * alpha_y;
return beckmann ? expf(-(sqr(H.x) + sqr(H.y)) / cos_NH2) / (M_PI_F * alpha2 * sqr(cos_NH2)) : if constexpr (m_type == MicrofacetType::BECKMANN) {
M_1_PI_F / (alpha2 * sqr(len_squared(H))); return expf(-(sqr(H.x) + sqr(H.y)) / cos_NH2) / (M_PI_F * alpha2 * sqr(cos_NH2));
}
/* m_type == MicrofacetType::GGX */
return M_1_PI_F / (alpha2 * sqr(len_squared(H)));
} }
ccl_device_forceinline void bsdf_microfacet_fresnel_color(ccl_private const ShaderData *sd, ccl_device_forceinline void bsdf_microfacet_fresnel_color(ccl_private const ShaderData *sd,
ccl_private MicrofacetBsdf *bsdf) ccl_private MicrofacetBsdf *bsdf)
{ {
kernel_assert(CLOSURE_IS_BSDF_MICROFACET_FRESNEL(bsdf->type)); kernel_assert(CLOSURE_IS_BSDF_MICROFACET_FRESNEL(bsdf->type));
float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
bsdf->extra->fresnel_color = interpolate_fresnel_color( bsdf->extra->fresnel_color = interpolate_fresnel_color(
sd->wi, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0); sd->wi, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0);
if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) {
bsdf->extra->fresnel_color *= 0.25f * bsdf->extra->clearcoat; bsdf->extra->fresnel_color *= 0.25f * bsdf->extra->clearcoat;
} }
bsdf->sample_weight *= average(bsdf->extra->fresnel_color); bsdf->sample_weight *= average(bsdf->extra->fresnel_color);
} }
template<bool beckmann> template<MicrofacetType m_type>
ccl_device Spectrum bsdf_microfacet_eval(ccl_private const ShaderClosure *sc, ccl_device Spectrum bsdf_microfacet_eval(ccl_private const ShaderClosure *sc,
const float3 Ng, const float3 Ng,
const float3 wi, const float3 wi,
const float3 wo, const float3 wo,
ccl_private float *pdf) ccl_private float *pdf)
{ {
ccl_private const MicrofacetBsdf *bsdf = (ccl_private const MicrofacetBsdf *)sc; ccl_private const MicrofacetBsdf *bsdf = (ccl_private const MicrofacetBsdf *)sc;
const bool m_refractive = (bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID) || const bool m_refractive = (bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID) ||
Show All 28 Lines if (alpha_x == alpha_y || m_refractive) { /* Isotropic. */
if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) {
D = bsdf_clearcoat_D(alpha2, cos_NH); D = bsdf_clearcoat_D(alpha2, cos_NH);
/* The masking-shadowing term for clearcoat has a fixed alpha of 0.25 /* The masking-shadowing term for clearcoat has a fixed alpha of 0.25
* => alpha2 = 0.25 * 0.25 */ * => alpha2 = 0.25 * 0.25 */
alpha2 = 0.0625f; alpha2 = 0.0625f;
} }
else { else {
D = bsdf_D<beckmann>(alpha2, cos_NH); D = bsdf_D<m_type>(alpha2, cos_NH);
} }
G1i = bsdf_G1<beckmann>(alpha2, cos_NI); G1i = bsdf_G1<m_type>(alpha2, cos_NI);
G1o = bsdf_G1<beckmann>(alpha2, cos_NO); G1o = bsdf_G1<m_type>(alpha2, cos_NO);
} }
else { /* Anisotropic. */ else { /* Anisotropic. */
float3 X, Y; float3 X, Y;
make_orthonormals_tangent(N, bsdf->T, &X, &Y); make_orthonormals_tangent(N, bsdf->T, &X, &Y);
const float3 local_H = make_float3(dot(X, H), dot(Y, H), cos_NH); const float3 local_H = make_float3(dot(X, H), dot(Y, H), cos_NH);
const float3 local_I = make_float3(dot(X, wi), dot(Y, wi), cos_NI); const float3 local_I = make_float3(dot(X, wi), dot(Y, wi), cos_NI);
const float3 local_O = make_float3(dot(X, wo), dot(Y, wo), cos_NO); const float3 local_O = make_float3(dot(X, wo), dot(Y, wo), cos_NO);
D = bsdf_aniso_D<beckmann>(alpha_x, alpha_y, local_H); D = bsdf_aniso_D<m_type>(alpha_x, alpha_y, local_H);
G1i = bsdf_aniso_G1<beckmann>(alpha_x, alpha_y, local_I); G1i = bsdf_aniso_G1<m_type>(alpha_x, alpha_y, local_I);
G1o = bsdf_aniso_G1<beckmann>(alpha_x, alpha_y, local_O); G1o = bsdf_aniso_G1<m_type>(alpha_x, alpha_y, local_O);
} }
const float common = G1i * D / cos_NI * const float common = G1i * D / cos_NI *
(m_refractive ? (m_refractive ?
sqr(bsdf->ior * inv_len_H) * fabsf(dot(H, wi) * dot(H, wo)) : sqr(bsdf->ior * inv_len_H) * fabsf(dot(H, wi) * dot(H, wo)) :
0.25f); 0.25f);
*pdf = common; *pdf = common;
const Spectrum F = m_refractive ? one_spectrum() : reflection_color(bsdf, wo, H); const Spectrum F = m_refractive ? one_spectrum() : reflection_color(bsdf, wo, H);
return F * G1o * common; return F * G1o * common;
} }
template<bool beckmann> template<MicrofacetType m_type>
ccl_device int bsdf_microfacet_sample(KernelGlobals kg, ccl_device int bsdf_microfacet_sample(KernelGlobals kg,
ccl_private const ShaderClosure *sc, ccl_private const ShaderClosure *sc,
float3 Ng, float3 Ng,
float3 wi, float3 wi,
float randu, float randu,
float randv, float randv,
ccl_private Spectrum *eval, ccl_private Spectrum *eval,
ccl_private float3 *wo, ccl_private float3 *wo,
Show All 23 Linesccl_device int bsdf_microfacet_sample(KernelGlobals kg,
else { else {
make_orthonormals_tangent(N, bsdf->T, &X, &Y); make_orthonormals_tangent(N, bsdf->T, &X, &Y);
} }
/* Importance sampling with distribution of visible normals. Vectors are transformed to local /* Importance sampling with distribution of visible normals. Vectors are transformed to local
* space before and after sampling. */ * space before and after sampling. */
float G1i; float G1i;
const float3 local_I = make_float3(dot(X, wi), dot(Y, wi), cos_NI); const float3 local_I = make_float3(dot(X, wi), dot(Y, wi), cos_NI);
const float3 local_H = microfacet_sample_stretched( const float3 local_H = microfacet_sample_stretched<m_type>(
kg, local_I, alpha_x, alpha_y, randu, randv, beckmann, &G1i); kg, local_I, alpha_x, alpha_y, randu, randv, &G1i);
const float3 H = X * local_H.x + Y * local_H.y + N * local_H.z; const float3 H = X * local_H.x + Y * local_H.y + N * local_H.z;
const float cos_NH = local_H.z; const float cos_NH = local_H.z;
const float cos_HI = dot(H, wi); const float cos_HI = dot(H, wi);
bool valid = beckmann; bool valid = false;
if (m_refractive) { if (m_refractive) {
float3 R, T; float3 R, T;
bool inside; bool inside;
float fresnel = fresnel_dielectric(m_eta, H, wi, &R, &T, &inside); float fresnel = fresnel_dielectric(m_eta, H, wi, &R, &T, &inside);
*wo = T; *wo = T;
valid = !inside && fresnel != 1.0f; valid = !inside && fresnel != 1.0f;
Show All 36 Lines if (alpha_x == alpha_y || m_refractive) { /* Isotropic. */
if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) {
D = bsdf_clearcoat_D(alpha2, cos_NH); D = bsdf_clearcoat_D(alpha2, cos_NH);
/* The masking-shadowing term for clearcoat has a fixed alpha of 0.25 /* The masking-shadowing term for clearcoat has a fixed alpha of 0.25
* => alpha2 = 0.25 * 0.25 */ * => alpha2 = 0.25 * 0.25 */
alpha2 = 0.0625f; alpha2 = 0.0625f;
/* Recalculate G1i. */ /* Recalculate G1i. */
G1i = bsdf_G1<beckmann>(alpha2, cos_NI); G1i = bsdf_G1<m_type>(alpha2, cos_NI);
} }
else { else {
D = bsdf_D<beckmann>(alpha2, cos_NH); D = bsdf_D<m_type>(alpha2, cos_NH);
} }
G1o = bsdf_G1<beckmann>(alpha2, cos_NO); G1o = bsdf_G1<m_type>(alpha2, cos_NO);
} }
else { /* Anisotropic. */ else { /* Anisotropic. */
const float3 local_O = make_float3(dot(X, *wo), dot(Y, *wo), cos_NO); const float3 local_O = make_float3(dot(X, *wo), dot(Y, *wo), cos_NO);
D = bsdf_aniso_D<beckmann>(alpha_x, alpha_y, local_H); D = bsdf_aniso_D<m_type>(alpha_x, alpha_y, local_H);
G1o = bsdf_aniso_G1<beckmann>(alpha_x, alpha_y, local_O); G1o = bsdf_aniso_G1<m_type>(alpha_x, alpha_y, local_O);
} }
const float cos_HO = dot(H, *wo); const float cos_HO = dot(H, *wo);
const float common = G1i * D / cos_NI * const float common = G1i * D / cos_NI *
(m_refractive ? fabsf(cos_HI * cos_HO) / sqr(cos_HO + cos_HI / m_eta) : (m_refractive ? fabsf(cos_HI * cos_HO) / sqr(cos_HO + cos_HI / m_eta) :
0.25f); 0.25f);
*pdf = common; *pdf = common;
▲ Show 20 Lines • Show All 93 Lines • ▼ Show 20 Lines
} }
ccl_device Spectrum bsdf_microfacet_ggx_eval(ccl_private const ShaderClosure *sc, ccl_device Spectrum bsdf_microfacet_ggx_eval(ccl_private const ShaderClosure *sc,
const float3 Ng, const float3 Ng,
const float3 wi, const float3 wi,
const float3 wo, const float3 wo,
ccl_private float *pdf) ccl_private float *pdf)
{ {
return bsdf_microfacet_eval<false>(sc, Ng, wi, wo, pdf); return bsdf_microfacet_eval<MicrofacetType::GGX>(sc, Ng, wi, wo, pdf);
} }
ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals kg, ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals kg,
ccl_private const ShaderClosure *sc, ccl_private const ShaderClosure *sc,
float3 Ng, float3 Ng,
float3 wi, float3 wi,
float randu, float randu,
float randv, float randv,
ccl_private Spectrum *eval, ccl_private Spectrum *eval,
ccl_private float3 *wo, ccl_private float3 *wo,
ccl_private float *pdf, ccl_private float *pdf,
ccl_private float2 *sampled_roughness, ccl_private float2 *sampled_roughness,
ccl_private float *eta) ccl_private float *eta)
{ {
return bsdf_microfacet_sample<false>( return bsdf_microfacet_sample<MicrofacetType::GGX>(
kg, sc, Ng, wi, randu, randv, eval, wo, pdf, sampled_roughness, eta); kg, sc, Ng, wi, randu, randv, eval, wo, pdf, sampled_roughness, eta);
} }
/* Beckmann microfacet with Smith shadow-masking from: /* Beckmann microfacet with Smith shadow-masking from:
* *
* Microfacet Models for Refraction through Rough Surfaces * Microfacet Models for Refraction through Rough Surfaces
* B. Walter, S. R. Marschner, H. Li, K. E. Torrance, EGSR 2007 */ * B. Walter, S. R. Marschner, H. Li, K. E. Torrance, EGSR 2007 */
Show All 32 Lines
} }
ccl_device Spectrum bsdf_microfacet_beckmann_eval(ccl_private const ShaderClosure *sc, ccl_device Spectrum bsdf_microfacet_beckmann_eval(ccl_private const ShaderClosure *sc,
const float3 Ng, const float3 Ng,
const float3 wi, const float3 wi,
const float3 wo, const float3 wo,
ccl_private float *pdf) ccl_private float *pdf)
{ {
return bsdf_microfacet_eval<true>(sc, Ng, wi, wo, pdf); return bsdf_microfacet_eval<MicrofacetType::BECKMANN>(sc, Ng, wi, wo, pdf);
} }
ccl_device int bsdf_microfacet_beckmann_sample(KernelGlobals kg, ccl_device int bsdf_microfacet_beckmann_sample(KernelGlobals kg,
ccl_private const ShaderClosure *sc, ccl_private const ShaderClosure *sc,
float3 Ng, float3 Ng,
float3 wi, float3 wi,
float randu, float randu,
float randv, float randv,
ccl_private Spectrum *eval, ccl_private Spectrum *eval,
ccl_private float3 *wo, ccl_private float3 *wo,
ccl_private float *pdf, ccl_private float *pdf,
ccl_private float2 *sampled_roughness, ccl_private float2 *sampled_roughness,
ccl_private float *eta) ccl_private float *eta)
{ {
return bsdf_microfacet_sample<true>( return bsdf_microfacet_sample<MicrofacetType::BECKMANN>(
kg, sc, Ng, wi, randu, randv, eval, wo, pdf, sampled_roughness, eta); kg, sc, Ng, wi, randu, randv, eval, wo, pdf, sampled_roughness, eta);
} }
CCL_NAMESPACE_END CCL_NAMESPACE_END