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@ -13,11 +13,7 @@ CCL_NAMESPACE_BEGIN
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typedef struct PrincipledHairExtra {
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/* Geometry data. */
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float3 Y, Z;
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float gamma_o, gamma_t;
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/* Precomputed Transmission and Fresnel term */
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Spectrum T;
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float f;
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float4 geom;
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} PrincipledHairExtra;
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typedef struct PrincipledHairBSDF {
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@ -25,16 +21,16 @@ typedef struct PrincipledHairBSDF {
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/* Absorption coefficient. */
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Spectrum sigma;
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/* Variance of the underlying logistic distribution, based on longitudinal roughness. */
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/* Variance of the underlying logistic distribution. */
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float v;
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/* Scale factor of the underlying logistic distribution, based on azimuthal roughness. */
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/* Scale factor of the underlying logistic distribution. */
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float s;
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/* Alternative value for v, used for the R lobe. */
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float v_R;
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/* Cuticle tilt angle. */
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float alpha;
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/* IOR. */
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float eta;
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/* Effective variance for the diffuse bounce only. */
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float m0_roughness;
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/* Extra closure. */
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ccl_private PrincipledHairExtra *extra;
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@ -135,9 +131,6 @@ ccl_device_inline float sample_trimmed_logistic(float u, float s)
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ccl_device_inline float azimuthal_scattering(
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float phi, int p, float s, float gamma_o, float gamma_t)
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{
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if (p == 3) {
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return M_1_2PI_F;
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}
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float phi_o = wrap_angle(phi - delta_phi(p, gamma_o, gamma_t));
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float val = trimmed_logistic(phi_o, s);
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return val;
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@ -162,45 +155,27 @@ ccl_device_inline float longitudinal_scattering(
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}
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}
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ccl_device_forceinline float hair_get_lobe_v(const ccl_private PrincipledHairBSDF *bsdf,
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const int lobe)
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{
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if (lobe == 0) {
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return bsdf->v_R;
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}
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else if (lobe == 1) {
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return 0.25f * bsdf->v;
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}
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else {
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return 4.0f * bsdf->v;
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}
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}
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#ifdef __HAIR__
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/* Set up the hair closure. */
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ccl_device int bsdf_principled_hair_setup(ccl_private ShaderData *sd,
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ccl_private PrincipledHairBSDF *bsdf,
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float u_rough,
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float u_coat_rough,
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float v_rough)
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ccl_private PrincipledHairBSDF *bsdf)
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{
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u_rough = clamp(u_rough, 0.001f, 1.0f);
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v_rough = clamp(v_rough, 0.001f, 1.0f);
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/* u_coat_rough is a multiplier that modifies u_rough for the R lobe. */
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float u_R_roughness = clamp(u_coat_rough * u_rough, 0.001f, 1.0f);
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bsdf->type = CLOSURE_BSDF_HAIR_PRINCIPLED_ID;
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bsdf->v = clamp(bsdf->v, 0.001f, 1.0f);
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bsdf->s = clamp(bsdf->s, 0.001f, 1.0f);
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/* Apply Primary Reflection Roughness modifier. */
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bsdf->m0_roughness = clamp(bsdf->m0_roughness * bsdf->v, 0.001f, 1.0f);
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/* Map from the azimuthal and the two longitudinal roughnesses to variance and scale factor. */
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bsdf->v = sqr(0.726f * u_rough + 0.812f * sqr(u_rough) + 3.700f * pow20(u_rough));
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bsdf->v_R = sqr(0.726f * u_R_roughness + 0.812f * sqr(u_R_roughness) +
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3.700f * pow20(u_R_roughness));
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bsdf->s = (0.265f * v_rough + 1.194f * sqr(v_rough) + 5.372f * pow22(v_rough)) * M_SQRT_PI_8_F;
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/* Map from roughness_u and roughness_v to variance and scale factor. */
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bsdf->v = sqr(0.726f * bsdf->v + 0.812f * sqr(bsdf->v) + 3.700f * pow20(bsdf->v));
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bsdf->s = (0.265f * bsdf->s + 1.194f * sqr(bsdf->s) + 5.372f * pow22(bsdf->s)) * M_SQRT_PI_8_F;
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bsdf->m0_roughness = sqr(0.726f * bsdf->m0_roughness + 0.812f * sqr(bsdf->m0_roughness) +
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3.700f * pow20(bsdf->m0_roughness));
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/* Compute local frame, aligned to curve tangent and ray direction. */
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float3 X = safe_normalize(sd->dPdu);
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bsdf->extra->Y = safe_normalize(cross(X, sd->wi));
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bsdf->extra->Z = safe_normalize(cross(X, bsdf->extra->Y));
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float3 Y = safe_normalize(cross(X, sd->wi));
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float3 Z = safe_normalize(cross(X, Y));
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/* h -1..0..1 means the rays goes from grazing the hair, to hitting it at
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* the center, to grazing the other edge. This is the sine of the angle
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@ -208,28 +183,13 @@ ccl_device int bsdf_principled_hair_setup(ccl_private ShaderData *sd,
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/* TODO: we convert this value to a cosine later and discard the sign, so
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* we could probably save some operations. */
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float h = (sd->type & PRIMITIVE_CURVE_RIBBON) ? -sd->v : dot(cross(sd->Ng, X), bsdf->extra->Z);
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float h = (sd->type & PRIMITIVE_CURVE_RIBBON) ? -sd->v : dot(cross(sd->Ng, X), Z);
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kernel_assert(fabsf(h) < 1.0f + 1e-4f);
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kernel_assert(isfinite_safe(Y));
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kernel_assert(isfinite_safe(h));
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const float sin_theta_o = dot(sd->wi, X);
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const float cos_theta_o = cos_from_sin(sin_theta_o);
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const float sin_theta_t = sin_theta_o / bsdf->eta;
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const float cos_theta_t = cos_from_sin(sin_theta_t);
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const float sin_gamma_o = h;
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const float cos_gamma_o = cos_from_sin(sin_gamma_o);
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bsdf->extra->gamma_o = safe_asinf(sin_gamma_o);
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const float sin_gamma_t = sin_gamma_o * cos_theta_o / sqrtf(sqr(bsdf->eta) - sqr(sin_theta_o));
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const float cos_gamma_t = cos_from_sin(sin_gamma_t);
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bsdf->extra->gamma_t = safe_asinf(sin_gamma_t);
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bsdf->extra->T = exp(-bsdf->sigma * (2.0f * cos_gamma_t / cos_theta_t));
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bsdf->extra->f = fresnel_dielectric_cos(cos_theta_o * cos_gamma_o, bsdf->eta);
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bsdf->extra->geom = make_float4(Y.x, Y.y, Y.z, h);
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return SD_BSDF | SD_BSDF_HAS_EVAL | SD_BSDF_NEEDS_LCG | SD_BSDF_HAS_TRANSMISSION;
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}
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@ -238,35 +198,35 @@ ccl_device int bsdf_principled_hair_setup(ccl_private ShaderData *sd,
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/* Given the Fresnel term and transmittance, generate the attenuation terms for each bounce. */
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ccl_device_inline void hair_attenuation(
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KernelGlobals kg, float f, Spectrum T, ccl_private Spectrum *Ap, ccl_private float *lobe_pdf)
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KernelGlobals kg, float f, Spectrum T, ccl_private Spectrum *Ap, ccl_private float *Ap_energy)
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{
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/* Primary specular (R). */
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Ap[0] = make_spectrum(f);
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lobe_pdf[0] = f;
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Ap_energy[0] = f;
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/* Transmission (TT). */
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Spectrum col = sqr(1.0f - f) * T;
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Ap[1] = col;
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lobe_pdf[1] = spectrum_to_gray(kg, col);
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Ap_energy[1] = spectrum_to_gray(kg, col);
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/* Secondary specular (TRT). */
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col *= T * f;
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Ap[2] = col;
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lobe_pdf[2] = spectrum_to_gray(kg, col);
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Ap_energy[2] = spectrum_to_gray(kg, col);
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/* Residual component (TRRT+). */
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col *= safe_divide(T * f, one_spectrum() - T * f);
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Ap[3] = col;
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lobe_pdf[3] = spectrum_to_gray(kg, col);
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Ap_energy[3] = spectrum_to_gray(kg, col);
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/* Normalize sampling weights. */
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float totweight = lobe_pdf[0] + lobe_pdf[1] + lobe_pdf[2] + lobe_pdf[3];
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float totweight = Ap_energy[0] + Ap_energy[1] + Ap_energy[2] + Ap_energy[3];
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float fac = safe_divide(1.0f, totweight);
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lobe_pdf[0] *= fac;
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lobe_pdf[1] *= fac;
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lobe_pdf[2] *= fac;
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lobe_pdf[3] *= fac;
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Ap_energy[0] *= fac;
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Ap_energy[1] *= fac;
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Ap_energy[2] *= fac;
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Ap_energy[3] *= fac;
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}
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/* Given the tilt angle, generate the rotated theta_i for the different bounces. */
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@ -288,120 +248,91 @@ ccl_device_inline void hair_alpha_angles(float sin_theta_i,
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angles[3] = fabsf(cos_theta_i * cos_1alpha + sin_theta_i * sin_1alpha);
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angles[4] = sin_theta_i * cos_4alpha - cos_theta_i * sin_4alpha;
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angles[5] = fabsf(cos_theta_i * cos_4alpha + sin_theta_i * sin_4alpha);
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angles[6] = sin_theta_i;
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angles[7] = cos_theta_i;
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}
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/* Since most of the implementation is the same between sampling and evaluation,
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* this shared function implements both.
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* For evaluation, wo is an input, and randu/randv are ignored.
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* For sampling, wo is an output, and randu/randv are used to pick it.
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*/
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template<bool do_sample>
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ccl_device int bsdf_principled_hair_impl(KernelGlobals kg,
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ccl_private const PrincipledHairBSDF *bsdf,
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ccl_private ShaderData *sd,
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ccl_private float3 *wo,
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ccl_private Spectrum *F,
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ccl_private float *pdf,
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float randu,
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float randv)
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{
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const float3 X = safe_normalize(sd->dPdu);
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const float3 Y = bsdf->extra->Y;
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const float3 Z = bsdf->extra->Z;
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kernel_assert(fabsf(dot(X, Y)) < 1e-3f);
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const float gamma_o = bsdf->extra->gamma_o;
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const float gamma_t = bsdf->extra->gamma_t;
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const float3 local_O = make_float3(dot(sd->wi, X), dot(sd->wi, Y), dot(sd->wi, Z));
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const float sin_theta_o = local_O.x;
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const float cos_theta_o = cos_from_sin(sin_theta_o);
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const float phi_o = atan2f(local_O.z, local_O.y);
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Spectrum Ap[4];
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float lobe_pdf[4];
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hair_attenuation(kg, bsdf->extra->f, bsdf->extra->T, Ap, lobe_pdf);
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float sin_theta_i, cos_theta_i, phi;
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int sampled_p = 0;
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if (do_sample) {
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/* Pick lobe for sampline */
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for (; sampled_p < 3; sampled_p++) {
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if (randu < lobe_pdf[sampled_p]) {
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break;
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}
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randu -= lobe_pdf[sampled_p];
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}
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/* Sample incoming direction */
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float v = hair_get_lobe_v(bsdf, sampled_p);
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float randw = lcg_step_float(&sd->lcg_state), randx = lcg_step_float(&sd->lcg_state);
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randw = max(randw, 1e-5f);
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const float fac = 1.0f + v * logf(randw + (1.0f - randw) * expf(-2.0f / v));
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sin_theta_i = -fac * sin_theta_o + cos_from_sin(fac) * cosf(M_2PI_F * randx) * cos_theta_o;
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cos_theta_i = cos_from_sin(sin_theta_i);
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if (sampled_p < 3) {
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float angles[8];
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hair_alpha_angles(sin_theta_i, cos_theta_i, -bsdf->alpha, angles);
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sin_theta_i = angles[2 * sampled_p];
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cos_theta_i = angles[2 * sampled_p + 1];
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phi = delta_phi(sampled_p, gamma_o, gamma_t) + sample_trimmed_logistic(randv, bsdf->s);
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}
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else {
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phi = M_2PI_F * randv;
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}
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const float phi_i = phi_o + phi;
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*wo = X * sin_theta_i + Y * cos_theta_i * cosf(phi_i) + Z * cos_theta_i * sinf(phi_i);
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}
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else {
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const float3 local_I = make_float3(dot(*wo, X), dot(*wo, Y), dot(*wo, Z));
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sin_theta_i = local_I.x;
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cos_theta_i = cos_from_sin(sin_theta_i);
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const float phi_i = atan2f(local_I.z, local_I.y);
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phi = phi_i - phi_o;
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}
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/* Evaluate throughput. */
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float angles[8];
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hair_alpha_angles(sin_theta_i, cos_theta_i, bsdf->alpha, angles);
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*F = zero_spectrum();
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*pdf = 0.0f;
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for (int p = 0; p < 4; p++) {
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const float Mp = longitudinal_scattering(
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angles[2 * p], angles[2 * p + 1], sin_theta_o, cos_theta_o, hair_get_lobe_v(bsdf, p));
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const float Np = azimuthal_scattering(phi, p, bsdf->s, gamma_o, gamma_t);
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*F += Ap[p] * Mp * Np;
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*pdf += lobe_pdf[p] * Mp * Np;
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kernel_assert(isfinite_safe(*F) && isfinite_safe(*pdf));
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|
|
|
}
|
|
|
|
|
|
|
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|
return sampled_p;
|
|
|
|
|
}
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|
/* Evaluation function for our shader. */
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ccl_device Spectrum bsdf_principled_hair_eval(KernelGlobals kg,
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|
ccl_private ShaderData *sd,
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|
ccl_private const ShaderData *sd,
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|
ccl_private const ShaderClosure *sc,
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|
float3 wo,
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|
const float3 wo,
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|
ccl_private float *pdf)
|
|
|
|
|
{
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|
kernel_assert(isfinite_safe(sd->P) && isfinite_safe(sd->ray_length));
|
|
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ccl_private const PrincipledHairBSDF *bsdf = (ccl_private const PrincipledHairBSDF *)sc;
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const float3 Y = float4_to_float3(bsdf->extra->geom);
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Spectrum eval;
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bsdf_principled_hair_impl<false>(kg, bsdf, sd, &wo, &eval, pdf, 0.0f, 0.0f);
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return eval;
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const float3 X = safe_normalize(sd->dPdu);
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kernel_assert(fabsf(dot(X, Y)) < 1e-3f);
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const float3 Z = safe_normalize(cross(X, Y));
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/* local_I is the illumination direction. */
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const float3 local_O = make_float3(dot(sd->wi, X), dot(sd->wi, Y), dot(sd->wi, Z));
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const float3 local_I = make_float3(dot(wo, X), dot(wo, Y), dot(wo, Z));
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const float sin_theta_o = local_O.x;
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const float cos_theta_o = cos_from_sin(sin_theta_o);
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const float phi_o = atan2f(local_O.z, local_O.y);
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const float sin_theta_t = sin_theta_o / bsdf->eta;
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const float cos_theta_t = cos_from_sin(sin_theta_t);
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const float sin_gamma_o = bsdf->extra->geom.w;
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const float cos_gamma_o = cos_from_sin(sin_gamma_o);
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const float gamma_o = safe_asinf(sin_gamma_o);
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const float sin_gamma_t = sin_gamma_o * cos_theta_o / sqrtf(sqr(bsdf->eta) - sqr(sin_theta_o));
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|
const float cos_gamma_t = cos_from_sin(sin_gamma_t);
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|
const float gamma_t = safe_asinf(sin_gamma_t);
|
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const Spectrum T = exp(-bsdf->sigma * (2.0f * cos_gamma_t / cos_theta_t));
|
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|
|
|
Spectrum Ap[4];
|
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|
|
|
float Ap_energy[4];
|
|
|
|
|
hair_attenuation(
|
|
|
|
|
kg, fresnel_dielectric_cos(cos_theta_o * cos_gamma_o, bsdf->eta), T, Ap, Ap_energy);
|
|
|
|
|
|
|
|
|
|
const float sin_theta_i = local_I.x;
|
|
|
|
|
const float cos_theta_i = cos_from_sin(sin_theta_i);
|
|
|
|
|
const float phi_i = atan2f(local_I.z, local_I.y);
|
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|
|
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|
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|
|
const float phi = phi_i - phi_o;
|
|
|
|
|
|
|
|
|
|
float angles[6];
|
|
|
|
|
hair_alpha_angles(sin_theta_i, cos_theta_i, bsdf->alpha, angles);
|
|
|
|
|
|
|
|
|
|
Spectrum F = zero_spectrum();
|
|
|
|
|
float F_energy = 0.0f;
|
|
|
|
|
|
|
|
|
|
/* Primary specular (R), Transmission (TT) and Secondary Specular (TRT). */
|
|
|
|
|
for (int i = 0; i < 3; i++) {
|
|
|
|
|
const float Mp = longitudinal_scattering(angles[2 * i],
|
|
|
|
|
angles[2 * i + 1],
|
|
|
|
|
sin_theta_o,
|
|
|
|
|
cos_theta_o,
|
|
|
|
|
(i == 0) ? bsdf->m0_roughness :
|
|
|
|
|
(i == 1) ? 0.25f * bsdf->v :
|
|
|
|
|
4.0f * bsdf->v);
|
|
|
|
|
const float Np = azimuthal_scattering(phi, i, bsdf->s, gamma_o, gamma_t);
|
|
|
|
|
F += Ap[i] * Mp * Np;
|
|
|
|
|
F_energy += Ap_energy[i] * Mp * Np;
|
|
|
|
|
kernel_assert(isfinite_safe(F) && isfinite_safe(F_energy));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Residual component (TRRT+). */
|
|
|
|
|
{
|
|
|
|
|
const float Mp = longitudinal_scattering(
|
|
|
|
|
sin_theta_i, cos_theta_i, sin_theta_o, cos_theta_o, 4.0f * bsdf->v);
|
|
|
|
|
const float Np = M_1_2PI_F;
|
|
|
|
|
F += Ap[3] * Mp * Np;
|
|
|
|
|
F_energy += Ap_energy[3] * Mp * Np;
|
|
|
|
|
kernel_assert(isfinite_safe(F) && isfinite_safe(F_energy));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
*pdf = F_energy;
|
|
|
|
|
return F;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Sampling function for the hair shader. */
|
|
|
|
|
ccl_device int bsdf_principled_hair_sample(KernelGlobals kg,
|
|
|
|
|
ccl_private const ShaderClosure *sc,
|
|
|
|
|
ccl_private ShaderData *sd,
|
|
|
|
@ -413,13 +344,118 @@ ccl_device int bsdf_principled_hair_sample(KernelGlobals kg,
|
|
|
|
|
ccl_private float2 *sampled_roughness,
|
|
|
|
|
ccl_private float *eta)
|
|
|
|
|
{
|
|
|
|
|
ccl_private const PrincipledHairBSDF *bsdf = (ccl_private const PrincipledHairBSDF *)sc;
|
|
|
|
|
ccl_private PrincipledHairBSDF *bsdf = (ccl_private PrincipledHairBSDF *)sc;
|
|
|
|
|
|
|
|
|
|
int p = bsdf_principled_hair_impl<true>(kg, bsdf, sd, wo, eval, pdf, randu, randv);
|
|
|
|
|
|
|
|
|
|
*sampled_roughness = make_float2(bsdf->v_R, bsdf->v_R);
|
|
|
|
|
*sampled_roughness = make_float2(bsdf->m0_roughness, bsdf->m0_roughness);
|
|
|
|
|
*eta = bsdf->eta;
|
|
|
|
|
|
|
|
|
|
const float3 Y = float4_to_float3(bsdf->extra->geom);
|
|
|
|
|
|
|
|
|
|
const float3 X = safe_normalize(sd->dPdu);
|
|
|
|
|
kernel_assert(fabsf(dot(X, Y)) < 1e-3f);
|
|
|
|
|
const float3 Z = safe_normalize(cross(X, Y));
|
|
|
|
|
|
|
|
|
|
const float3 local_O = make_float3(dot(sd->wi, X), dot(sd->wi, Y), dot(sd->wi, Z));
|
|
|
|
|
|
|
|
|
|
float2 u[2];
|
|
|
|
|
u[0] = make_float2(randu, randv);
|
|
|
|
|
u[1].x = lcg_step_float(&sd->lcg_state);
|
|
|
|
|
u[1].y = lcg_step_float(&sd->lcg_state);
|
|
|
|
|
|
|
|
|
|
const float sin_theta_o = local_O.x;
|
|
|
|
|
const float cos_theta_o = cos_from_sin(sin_theta_o);
|
|
|
|
|
const float phi_o = atan2f(local_O.z, local_O.y);
|
|
|
|
|
|
|
|
|
|
const float sin_theta_t = sin_theta_o / bsdf->eta;
|
|
|
|
|
const float cos_theta_t = cos_from_sin(sin_theta_t);
|
|
|
|
|
|
|
|
|
|
const float sin_gamma_o = bsdf->extra->geom.w;
|
|
|
|
|
const float cos_gamma_o = cos_from_sin(sin_gamma_o);
|
|
|
|
|
const float gamma_o = safe_asinf(sin_gamma_o);
|
|
|
|
|
|
|
|
|
|
const float sin_gamma_t = sin_gamma_o * cos_theta_o / sqrtf(sqr(bsdf->eta) - sqr(sin_theta_o));
|
|
|
|
|
const float cos_gamma_t = cos_from_sin(sin_gamma_t);
|
|
|
|
|
const float gamma_t = safe_asinf(sin_gamma_t);
|
|
|
|
|
|
|
|
|
|
const Spectrum T = exp(-bsdf->sigma * (2.0f * cos_gamma_t / cos_theta_t));
|
|
|
|
|
Spectrum Ap[4];
|
|
|
|
|
float Ap_energy[4];
|
|
|
|
|
hair_attenuation(
|
|
|
|
|
kg, fresnel_dielectric_cos(cos_theta_o * cos_gamma_o, bsdf->eta), T, Ap, Ap_energy);
|
|
|
|
|
|
|
|
|
|
int p = 0;
|
|
|
|
|
for (; p < 3; p++) {
|
|
|
|
|
if (u[0].x < Ap_energy[p]) {
|
|
|
|
|
break;
|
|
|
|
|
}
|
|
|
|
|
u[0].x -= Ap_energy[p];
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
float v = bsdf->v;
|
|
|
|
|
if (p == 1) {
|
|
|
|
|
v *= 0.25f;
|
|
|
|
|
}
|
|
|
|
|
if (p >= 2) {
|
|
|
|
|
v *= 4.0f;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
u[1].x = max(u[1].x, 1e-5f);
|
|
|
|
|
const float fac = 1.0f + v * logf(u[1].x + (1.0f - u[1].x) * expf(-2.0f / v));
|
|
|
|
|
float sin_theta_i = -fac * sin_theta_o +
|
|
|
|
|
cos_from_sin(fac) * cosf(M_2PI_F * u[1].y) * cos_theta_o;
|
|
|
|
|
float cos_theta_i = cos_from_sin(sin_theta_i);
|
|
|
|
|
|
|
|
|
|
float angles[6];
|
|
|
|
|
if (p < 3) {
|
|
|
|
|
hair_alpha_angles(sin_theta_i, cos_theta_i, -bsdf->alpha, angles);
|
|
|
|
|
sin_theta_i = angles[2 * p];
|
|
|
|
|
cos_theta_i = angles[2 * p + 1];
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
float phi;
|
|
|
|
|
if (p < 3) {
|
|
|
|
|
phi = delta_phi(p, gamma_o, gamma_t) + sample_trimmed_logistic(u[0].y, bsdf->s);
|
|
|
|
|
}
|
|
|
|
|
else {
|
|
|
|
|
phi = M_2PI_F * u[0].y;
|
|
|
|
|
}
|
|
|
|
|
const float phi_i = phi_o + phi;
|
|
|
|
|
|
|
|
|
|
hair_alpha_angles(sin_theta_i, cos_theta_i, bsdf->alpha, angles);
|
|
|
|
|
|
|
|
|
|
Spectrum F = zero_spectrum();
|
|
|
|
|
float F_energy = 0.0f;
|
|
|
|
|
|
|
|
|
|
/* Primary specular (R), Transmission (TT) and Secondary Specular (TRT). */
|
|
|
|
|
for (int i = 0; i < 3; i++) {
|
|
|
|
|
const float Mp = longitudinal_scattering(angles[2 * i],
|
|
|
|
|
angles[2 * i + 1],
|
|
|
|
|
sin_theta_o,
|
|
|
|
|
cos_theta_o,
|
|
|
|
|
(i == 0) ? bsdf->m0_roughness :
|
|
|
|
|
(i == 1) ? 0.25f * bsdf->v :
|
|
|
|
|
4.0f * bsdf->v);
|
|
|
|
|
const float Np = azimuthal_scattering(phi, i, bsdf->s, gamma_o, gamma_t);
|
|
|
|
|
F += Ap[i] * Mp * Np;
|
|
|
|
|
F_energy += Ap_energy[i] * Mp * Np;
|
|
|
|
|
kernel_assert(isfinite_safe(F) && isfinite_safe(F_energy));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Residual component (TRRT+). */
|
|
|
|
|
{
|
|
|
|
|
const float Mp = longitudinal_scattering(
|
|
|
|
|
sin_theta_i, cos_theta_i, sin_theta_o, cos_theta_o, 4.0f * bsdf->v);
|
|
|
|
|
const float Np = M_1_2PI_F;
|
|
|
|
|
F += Ap[3] * Mp * Np;
|
|
|
|
|
F_energy += Ap_energy[3] * Mp * Np;
|
|
|
|
|
kernel_assert(isfinite_safe(F) && isfinite_safe(F_energy));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
*eval = F;
|
|
|
|
|
*pdf = F_energy;
|
|
|
|
|
|
|
|
|
|
*wo = X * sin_theta_i + Y * cos_theta_i * cosf(phi_i) + Z * cos_theta_i * sinf(phi_i);
|
|
|
|
|
|
|
|
|
|
return LABEL_GLOSSY | ((p == 0) ? LABEL_REFLECT : LABEL_TRANSMIT);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
@ -430,30 +466,29 @@ ccl_device void bsdf_principled_hair_blur(ccl_private ShaderClosure *sc, float r
|
|
|
|
|
|
|
|
|
|
bsdf->v = fmaxf(roughness, bsdf->v);
|
|
|
|
|
bsdf->s = fmaxf(roughness, bsdf->s);
|
|
|
|
|
bsdf->v_R = fmaxf(roughness, bsdf->v_R);
|
|
|
|
|
bsdf->m0_roughness = fmaxf(roughness, bsdf->m0_roughness);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Hair Albedo */
|
|
|
|
|
|
|
|
|
|
ccl_device_inline float bsdf_principled_hair_albedo_roughness_scale(const float u_rough)
|
|
|
|
|
ccl_device_inline float bsdf_principled_hair_albedo_roughness_scale(
|
|
|
|
|
const float azimuthal_roughness)
|
|
|
|
|
{
|
|
|
|
|
const float x = u_rough;
|
|
|
|
|
const float x = azimuthal_roughness;
|
|
|
|
|
return (((((0.245f * x) + 5.574f) * x - 10.73f) * x + 2.532f) * x - 0.215f) * x + 5.969f;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ccl_device Spectrum bsdf_principled_hair_albedo(ccl_private const ShaderClosure *sc)
|
|
|
|
|
{
|
|
|
|
|
ccl_private PrincipledHairBSDF *bsdf = (ccl_private PrincipledHairBSDF *)sc;
|
|
|
|
|
/* This is simply the sum of the four Ap terms in hair_attenuation. */
|
|
|
|
|
const float3 T = bsdf->extra->T;
|
|
|
|
|
const float f = bsdf->extra->f;
|
|
|
|
|
return safe_divide(T * (1.0f - 2.0f * f) + make_spectrum(f), one_spectrum() - f * T);
|
|
|
|
|
return exp(-sqrt(bsdf->sigma) * bsdf_principled_hair_albedo_roughness_scale(bsdf->v));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ccl_device_inline Spectrum bsdf_principled_hair_sigma_from_reflectance(const Spectrum color,
|
|
|
|
|
const float u_rough)
|
|
|
|
|
ccl_device_inline Spectrum
|
|
|
|
|
bsdf_principled_hair_sigma_from_reflectance(const Spectrum color, const float azimuthal_roughness)
|
|
|
|
|
{
|
|
|
|
|
const Spectrum sigma = log(color) / bsdf_principled_hair_albedo_roughness_scale(u_rough);
|
|
|
|
|
const Spectrum sigma = log(color) /
|
|
|
|
|
bsdf_principled_hair_albedo_roughness_scale(azimuthal_roughness);
|
|
|
|
|
return sigma * sigma;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|