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Fix variable passed to `fresnel()` being `NaN` sometimes

This commit is contained in:
Weizhen Huang 2022-12-19 20:03:03 +01:00
parent bf0075f886
commit 028918661a
1 changed files with 23 additions and 15 deletions
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38
intern/cycles/kernel/closure/bsdf_hair_microfacet.h
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@ -279,7 +279,7 @@ ccl_device float D(const bool beckmann, const float roughness, const float3 m, c
* `cos_theta_t`, as it is used when computing the direction of the refracted ray. */
ccl_device float fresnel(float cos_theta_i, float eta, ccl_private float &cos_theta_t)
{
kernel_assert(cos_theta_i >= 0.f); /* FIXME: cos_theta_i could be NaN. */
kernel_assert(!isnan_safe(cos_theta_i));
/* Special cases. */
if (eta == 1.f) {
@ -444,10 +444,10 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
/* dot(wi, wmi) > 0 */
const float tan_tilt = tanf(tilt);
float phi_m_max = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f));
const float phi_m_max = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f)) - 1e-3f;
if (isnan_safe(phi_m_max))
return zero_float3();
float phi_m_min = -phi_m_max;
const float phi_m_min = -phi_m_max;
/* dot(wo, wmo) < 0 */
float tmp1 = acosf(fminf(tan_tilt * tan_theta(wo), 0.f));
@ -475,8 +475,9 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
const float3 wh1 = sample_wh(kg, beckmann, roughness, wi, wmi, sample1);
const float dot_wi_wh1 = dot(wi, wh1);
if (dot_wi_wh1 <= 1e-5f)
if (!(dot_wi_wh1 > 0)) {
continue;
}
float cos_theta_t1;
const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1);
@ -534,8 +535,9 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
float3 wh2 = sample_wh(kg, beckmann, roughness, -wt, wmt, sample2);
const float cos_th2 = dot(-wt, wh2);
if (cos_th2 <= 1e-5f)
if (!(cos_th2 > 0)) {
continue;
}
const float R2 = fresnel_dielectric_cos(cos_th2, inv_eta);
float3 wtr = -reflect(wt, wh2);
@ -678,7 +680,7 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
const float3 wr = -reflect(wi, wh1);
/* ensure that this is a valid sample */
if (dot(wr, wh1) <= 0.f || dot(wr, wmi) <= 0.f || !microfacet_visible(wi, wr, wmi_, wh1)) {
if (!(dot(wr, wh1) > 0.f) || !(dot(wr, wmi) > 0.f) || !microfacet_visible(wi, wr, wmi_, wh1)) {
*pdf = 0.f;
return LABEL_NONE;
}
@ -831,6 +833,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_elliptic(ccl_private const ShaderC
/* get elliptical cross section characteristic */
const float a = 1.f;
/* TODO: rename this as aspect ratio? e is in [0, 0.85], b is in [0.52, 1]. */
const float b = bsdf->extra->eccentricity;
const float e2 = 1.f - sqr(b / a);
@ -865,8 +868,8 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_elliptic(ccl_private const ShaderC
phi_m_max1 -= M_2PI_F;
}
const float phi_m_min = fmaxf(phi_m_min1, phi_m_min2) + .001f;
const float phi_m_max = fminf(phi_m_max1, phi_m_max2) - .001f;
const float phi_m_min = fmaxf(phi_m_min1, phi_m_min2) + 1e-3f;
const float phi_m_max = fminf(phi_m_max1, phi_m_max2) - 1e-3f;
if (phi_m_min > phi_m_max)
return R;
@ -950,8 +953,8 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
const float b = bsdf->extra->eccentricity;
const float e2 = 1.f - sqr(b / a);
float gamma_m_min = to_gamma(phi_m_min, a, b);
float gamma_m_max = to_gamma(phi_m_max, a, b);
float gamma_m_min = to_gamma(phi_m_min, a, b) + 1e-3f;
float gamma_m_max = to_gamma(phi_m_max, a, b) - 1e-3f;
if (gamma_m_max < gamma_m_min)
gamma_m_max += M_2PI_F;
@ -975,8 +978,9 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
const float3 wh1 = sample_wh(kg, beckmann, roughness, wi, wmi, sample1);
const float dot_wi_wh1 = dot(wi, wh1);
if (dot_wi_wh1 <= 1e-5f)
if (!(dot_wi_wh1 > 0)) {
continue;
}
float cos_theta_t1;
const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1);
@ -997,12 +1001,14 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
const float2 pi = to_point(gamma_mi, a, b);
const float2 pt = to_point(gamma_mt + M_PI_F, a, b);
/* TODO: check the definition of mu_a. */
/* TODO: exp -> expf */
const float3 A_t = exp(-mu_a * len(pi - pt) / cos_theta(wt));
/* TT */
if (bsdf->extra->TT > 0.f) {
/* total internal reflection */
/* Total internal reflection otherwise. */
if (dot(wo, wt) >= inv_eta - 1e-5f) {
/* microfacet visiblity from macronormal */
@ -1040,8 +1046,9 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
const float3 wh2 = sample_wh(kg, beckmann, roughness, -wt, wmt, sample2);
const float cos_th2 = dot(-wt, wh2);
if (cos_th2 <= 1e-5f)
if (!(cos_th2 > 0)) {
continue;
}
const float R2 = fresnel_dielectric_cos(cos_th2, inv_eta);
const float3 wtr = -reflect(wt, wh2);
@ -1220,7 +1227,7 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
const float3 wr = -reflect(wi, wh1);
/* ensure that this is a valid sample */
if (dot(wr, wh1) <= 0.f || dot(wr, wmi) <= 0.f || !microfacet_visible(wi, wr, wmi_, wh1)) {
if (!(dot(wr, wh1) > 0.f) || !(dot(wr, wmi) > 0.f) || !microfacet_visible(wi, wr, wmi_, wh1)) {
*pdf = 0.f;
return LABEL_NONE;
}
@ -1263,8 +1270,9 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
wtt = -refract_angle(-wt, wh2, cos_theta_t2, *eta);
if (dot(wtt, wmt) < 0.f && cos_theta_t2 != 0.f) /* total internal reflection */
if (dot(wtt, wmt) < 0.f && cos_theta_t2 != 0.f) {
TT = bsdf->extra->TT * T1 * A_t * T2;
}
/* sample TRT lobe */
const float phi_tr = dir_phi(wtr);