[Bf-blender-cvs] [a2dd0c5] cycles_disney_brdf: Fixed glossy reflections and refractions for low roughness values and cleaned up the code.
Pascal Schoen
noreply at git.blender.org
Wed Oct 26 09:07:52 CEST 2016
Commit: a2dd0c5fafdabe1573299170fb3be98a3e46d17a
Author: Pascal Schoen
Date: Wed Oct 26 08:51:10 2016 +0200
Branches: cycles_disney_brdf
https://developer.blender.org/rBa2dd0c5fafdabe1573299170fb3be98a3e46d17a
Fixed glossy reflections and refractions for low roughness values and
cleaned up the code.
For low roughness values, the reflections had some strange behavior.
===================================================================
M intern/cycles/kernel/closure/bsdf_microfacet.h
M intern/cycles/kernel/closure/bsdf_microfacet_multi_impl.h
M intern/cycles/kernel/closure/bsdf_reflection.h
M intern/cycles/kernel/closure/bsdf_util.h
M intern/cycles/kernel/svm/svm_closure.h
===================================================================
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet.h b/intern/cycles/kernel/closure/bsdf_microfacet.h
index ecc37cd..57e3dae 100644
--- a/intern/cycles/kernel/closure/bsdf_microfacet.h
+++ b/intern/cycles/kernel/closure/bsdf_microfacet.h
@@ -37,7 +37,7 @@ CCL_NAMESPACE_BEGIN
typedef ccl_addr_space struct MicrofacetExtra {
float3 color, cspec0;
- bool use_fresnel, is_disney_clearcoat, initial_outside, only_refractions, only_reflections;
+ bool use_fresnel, is_disney_clearcoat;
} MicrofacetExtra;
typedef ccl_addr_space struct MicrofacetBsdf {
@@ -234,22 +234,21 @@ ccl_device_forceinline float3 microfacet_sample_stretched(
return normalize(make_float3(-slope_x, -slope_y, 1.0f));
}
-/* Calculate the fresnel color which is a blend between white and the F0 color */
-ccl_device_forceinline float3 fresnel_color(const MicrofacetBsdf *bsdf, float3 L, float3 H) {
+/* Calculate the reflection color
+ *
+ * If fresnel is used, the color is an interpolation of the F0 color and white
+ * with respect to the fresnel
+ *
+ * Else it is simply white
+ */
+ccl_device_forceinline float3 reflection_color(const MicrofacetBsdf *bsdf, float3 L, float3 H) {
float3 F = make_float3(1.0f, 1.0f, 1.0f);
if(bsdf->extra) {
if(bsdf->extra->use_fresnel) {
- /* Calculate the fresnel interpolation factor
- * The value from fresnel_dielectric_cos(...) has to be normalized because
- * the cspec0 keeps the F0 color
- */
float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
- float F0_norm = 1.0f / (1.0f - F0);
- float FH = (fresnel_dielectric_cos(dot(L, H), bsdf->ior) - F0) * F0_norm;
- /* Blend between white and a specular color with respect to the fresnel */
- F = bsdf->extra->cspec0 * (1.0f - FH) + make_float3(1.0f, 1.0f, 1.0f) * FH;
+ F = interpolate_fresnel_color(L, H, bsdf->ior, F0, bsdf->extra->cspec0);
}
}
@@ -409,13 +408,14 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
- /* eq. 34: now calculate G1(i,m) and G1(o,m) */
if(bsdf->extra) {
if(bsdf->extra->is_disney_clearcoat) {
+ /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */
alpha2 = 0.0625f;
}
}
+ /* eq. 34: now calculate G1(i,m) and G1(o,m) */
G1o = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
}
@@ -461,7 +461,7 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
/* eq. 20 */
float common = D * 0.25f / cosNO;
- float3 F = fresnel_color(bsdf, omega_in, m);
+ float3 F = reflection_color(bsdf, omega_in, m);
float3 out = F * G * common;
@@ -529,12 +529,10 @@ ccl_device float3 bsdf_microfacet_ggx_eval_transmit(const ShaderClosure *sc, con
* pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2 */
float common = D * (m_eta * m_eta) / (cosNO * Ht2);
- float3 F = fresnel_color(bsdf, omega_in, Ht);
-
- float3 out = G * fabsf(cosHI * cosHO) * common * F;
+ float out = G * fabsf(cosHI * cosHO) * common;
*pdf = G1o * fabsf(cosHO * cosHI) * common;
- return out;
+ return make_float3(out, out, out);
}
ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure *sc, float3 Ng, float3 I, float3 dIdx, float3 dIdy, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
@@ -579,6 +577,14 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
/* some high number for MIS */
*pdf = 1e6f;
*eval = make_float3(1e6f, 1e6f, 1e6f);
+
+ /* if fresnel is used, calculate the color with reflection_color(...) */
+ if(bsdf->extra) {
+ if(bsdf->extra->use_fresnel) {
+ *pdf = 1.0f;
+ *eval = reflection_color(bsdf, *omega_in, m);
+ }
+ }
}
else {
/* microfacet normal is visible to this ray */
@@ -599,9 +605,11 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
/* eq. 34: now calculate G1(i,m) */
if(bsdf->extra) {
if(bsdf->extra->is_disney_clearcoat) {
- // recalculate G1o
- G1o = 2 / (1 + safe_sqrtf(1 + 0.0625f * (1 - cosNO * cosNO) / (cosNO * cosNO)));
+ /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */
alpha2 = 0.0625f;
+
+ /* recalculate G1o */
+ G1o = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
}
}
@@ -637,7 +645,7 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
float common = (G1o * D) * 0.25f / cosNO;
*pdf = common;
- float3 F = fresnel_color(bsdf, *omega_in, m);
+ float3 F = reflection_color(bsdf, *omega_in, m);
*eval = G1i * common * F;
}
@@ -701,12 +709,10 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
/* see eval function for derivation */
float common = (G1o * D) * (m_eta * m_eta) / (cosNO * Ht2);
- float3 F = fresnel_color(bsdf, *omega_in, m);
-
- float3 out = G1i * fabsf(cosHI * cosHO) * common * F;
+ float out = G1i * fabsf(cosHI * cosHO) * common;
*pdf = cosHO * fabsf(cosHI) * common;
- *eval = out;
+ *eval = make_float3(out, out, out);
}
}
}
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet_multi_impl.h b/intern/cycles/kernel/closure/bsdf_microfacet_multi_impl.h
index 076d371..efd0fae 100644
--- a/intern/cycles/kernel/closure/bsdf_microfacet_multi_impl.h
+++ b/intern/cycles/kernel/closure/bsdf_microfacet_multi_impl.h
@@ -83,16 +83,14 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
else
eval *= -lambda_r * beta(-lambda_r, shadowing_lambda+1.0f);
- float3 eval2;
+ float3 eval_fresnel;
float3 t_color = cspec0;
- float3 throughput2 = make_float3(1.0f, 1.0f, 1.0f);
+ float3 throughput_fresnel = make_float3(1.0f, 1.0f, 1.0f);
float F0 = fresnel_dielectric_cos(1.0f, eta);
- float F0_norm = 1.0f / (1.0f - F0);
if(use_fresnel) {
- float FH = (fresnel_dielectric_cos(dot(wi, normalize(wi + wo)), eta) - F0) * F0_norm;
- throughput2 = cspec0 * (1.0f - FH) + make_float3(1.0f, 1.0f, 1.0f) * FH;
+ throughput_fresnel = interpolate_fresnel_color(wi, normalize(wi + wo), eta, F0, cspec0);
- eval2 = throughput2 * eval;
+ eval_fresnel = throughput_fresnel * eval;
}
#elif defined(MF_MULTI_DIFFUSE)
/* Diffuse has no special closed form for the single scattering bounce */
@@ -112,16 +110,14 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
eval = make_float3(val, val, val);
}
- float3 eval2;
+ float3 eval_fresnel;
float3 t_color = cspec0;
- float3 throughput2 = make_float3(1.0f, 1.0f, 1.0f);
+ float3 throughput_fresnel = make_float3(1.0f, 1.0f, 1.0f);
float F0 = fresnel_dielectric_cos(1.0f, eta);
- float F0_norm = 1.0f / (1.0f - F0);
if(use_fresnel) {
- float FH = (fresnel_dielectric_cos(dot(wi, normalize(wi + wo)), eta) - F0) * F0_norm;
- throughput2 = cspec0 * (1.0f - FH) + make_float3(1.0f, 1.0f, 1.0f) * FH;
+ throughput_fresnel = interpolate_fresnel_color(wi, normalize(wi + wo), eta, F0, cspec0);
- eval2 = throughput2 * val;
+ eval_fresnel = throughput_fresnel * val;
}
#endif
@@ -155,7 +151,7 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
else
phase = mf_eval_phase_glass(wr, lambda_r, -wo, !wo_outside, alpha, 1.0f / eta);
- eval2 = throughput2 * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
+ eval_fresnel = throughput_fresnel * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
}
#endif
if(order > 0) {
@@ -168,14 +164,14 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
phase = mf_eval_phase_glass(wr, lambda_r, -wo, !wo_outside, alpha, 1.0f/eta);
if(use_fresnel)
- eval2 += throughput2 * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
+ eval_fresnel += throughput_fresnel * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
#elif defined(MF_MULTI_DIFFUSE)
phase = mf_eval_phase_diffuse(wo, wm);
#else /* MF_MULTI_GLOSSY */
phase = mf_eval_phase_glossy(wr, lambda_r, wo, alpha, n, k) * throughput;
if(use_fresnel)
- eval2 += throughput2 * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
+ eval_fresnel += throughput_fresnel * phase * mf_G1(wo_outside ? wo : -wo, mf_C1((outside == wo_outside) ? hr : -hr), shadowing_lambda);
#endif
eval += throughput * phase * mf_G1(wo_outside? wo: -wo, mf_C1((outside == wo_outside)? hr: -hr), shadowing_lambda);
}
@@ -192,14 +188,13 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
}
if(use_fresnel && !next_outside) {
- throughput2 *= color;
+ throughput_fresnel *= color;
}
else if(use_fresnel) {
- float FH = (fresnel_dielectric_cos(dot(wi_prev, wm), eta) - F0) * F0_norm;
- t_color = cspec0 * (1.0f - FH) + make_float3(1.0f, 1.0f, 1.0f) * FH;
+ t_color = interpolate_fresnel_color(wi_prev, wm, eta, F0, cspec0);
if(order > 0)
- throughput2 *= t_color;
+ throughput_fresnel *= t_color;
}
#elif defined(MF_MULTI_DIFFUSE)
wr = mf_sample_phase_diffuse(wm,
@@ -207,14 +202,13 @@ ccl_device_forceinline float3 MF_FUNCTION_FULL_NAME(mf_eval)(
lcg_step_float_addrspace(lcg_state));
#else /* MF_MULTI_
@@ Diff output truncated at 10240 characters. @@
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