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-rw-r--r--intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h240
1 files changed, 116 insertions, 124 deletions
diff --git a/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h b/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
index cfe1ced43f2..14a4094d485 100644
--- a/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
+++ b/intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h
@@ -39,11 +39,10 @@ ccl_device_inline float bsdf_ashikhmin_shirley_roughness_to_exponent(float rough
return 2.0f / (roughness * roughness) - 2.0f;
}
-ccl_device_forceinline Spectrum
-bsdf_ashikhmin_shirley_eval_reflect(ccl_private const ShaderClosure *sc,
- const float3 I,
- const float3 omega_in,
- ccl_private float *pdf)
+ccl_device_forceinline Spectrum bsdf_ashikhmin_shirley_eval(ccl_private const ShaderClosure *sc,
+ const float3 I,
+ const float3 omega_in,
+ ccl_private float *pdf)
{
ccl_private const MicrofacetBsdf *bsdf = (ccl_private const MicrofacetBsdf *)sc;
float3 N = bsdf->N;
@@ -53,70 +52,60 @@ bsdf_ashikhmin_shirley_eval_reflect(ccl_private const ShaderClosure *sc,
float out = 0.0f;
- if (fmaxf(bsdf->alpha_x, bsdf->alpha_y) <= 1e-4f) {
+ if (fmaxf(bsdf->alpha_x, bsdf->alpha_y) <= 1e-4f || !(NdotI > 0.0f && NdotO > 0.0f)) {
*pdf = 0.0f;
return zero_spectrum();
}
- if (NdotI > 0.0f && NdotO > 0.0f) {
- NdotI = fmaxf(NdotI, 1e-6f);
- NdotO = fmaxf(NdotO, 1e-6f);
- float3 H = normalize(omega_in + I);
- float HdotI = fmaxf(fabsf(dot(H, I)), 1e-6f);
- float HdotN = fmaxf(dot(H, N), 1e-6f);
-
- /* pump from original paper
- * (first derivative disc., but cancels the HdotI in the pdf nicely) */
- float pump = 1.0f / fmaxf(1e-6f, (HdotI * fmaxf(NdotO, NdotI)));
- /* pump from d-brdf paper */
- /*float pump = 1.0f / fmaxf(1e-4f, ((NdotO + NdotI) * (NdotO*NdotI))); */
-
- float n_x = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_x);
- float n_y = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_y);
-
- if (n_x == n_y) {
- /* isotropic */
- float e = n_x;
- float lobe = powf(HdotN, e);
- float norm = (n_x + 1.0f) / (8.0f * M_PI_F);
-
- out = NdotO * norm * lobe * pump;
- /* this is p_h / 4(H.I) (conversion from 'wh measure' to 'wi measure', eq. 8 in paper). */
- *pdf = norm * lobe / HdotI;
+
+ NdotI = fmaxf(NdotI, 1e-6f);
+ NdotO = fmaxf(NdotO, 1e-6f);
+ float3 H = normalize(omega_in + I);
+ float HdotI = fmaxf(fabsf(dot(H, I)), 1e-6f);
+ float HdotN = fmaxf(dot(H, N), 1e-6f);
+
+ /* pump from original paper
+ * (first derivative disc., but cancels the HdotI in the pdf nicely) */
+ float pump = 1.0f / fmaxf(1e-6f, (HdotI * fmaxf(NdotO, NdotI)));
+ /* pump from d-brdf paper */
+ /*float pump = 1.0f / fmaxf(1e-4f, ((NdotO + NdotI) * (NdotO*NdotI))); */
+
+ float n_x = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_x);
+ float n_y = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_y);
+
+ if (n_x == n_y) {
+ /* isotropic */
+ float e = n_x;
+ float lobe = powf(HdotN, e);
+ float norm = (n_x + 1.0f) / (8.0f * M_PI_F);
+
+ out = NdotO * norm * lobe * pump;
+ /* this is p_h / 4(H.I) (conversion from 'wh measure' to 'wi measure', eq. 8 in paper). */
+ *pdf = norm * lobe / HdotI;
+ }
+ else {
+ /* anisotropic */
+ float3 X, Y;
+ make_orthonormals_tangent(N, bsdf->T, &X, &Y);
+
+ float HdotX = dot(H, X);
+ float HdotY = dot(H, Y);
+ float lobe;
+ if (HdotN < 1.0f) {
+ float e = (n_x * HdotX * HdotX + n_y * HdotY * HdotY) / (1.0f - HdotN * HdotN);
+ lobe = powf(HdotN, e);
}
else {
- /* anisotropic */
- float3 X, Y;
- make_orthonormals_tangent(N, bsdf->T, &X, &Y);
-
- float HdotX = dot(H, X);
- float HdotY = dot(H, Y);
- float lobe;
- if (HdotN < 1.0f) {
- float e = (n_x * HdotX * HdotX + n_y * HdotY * HdotY) / (1.0f - HdotN * HdotN);
- lobe = powf(HdotN, e);
- }
- else {
- lobe = 1.0f;
- }
- float norm = sqrtf((n_x + 1.0f) * (n_y + 1.0f)) / (8.0f * M_PI_F);
-
- out = NdotO * norm * lobe * pump;
- *pdf = norm * lobe / HdotI;
+ lobe = 1.0f;
}
+ float norm = sqrtf((n_x + 1.0f) * (n_y + 1.0f)) / (8.0f * M_PI_F);
+
+ out = NdotO * norm * lobe * pump;
+ *pdf = norm * lobe / HdotI;
}
return make_spectrum(out);
}
-ccl_device Spectrum bsdf_ashikhmin_shirley_eval_transmit(ccl_private const ShaderClosure *sc,
- const float3 I,
- const float3 omega_in,
- ccl_private float *pdf)
-{
- *pdf = 0.0f;
- return zero_spectrum();
-}
-
ccl_device_inline void bsdf_ashikhmin_shirley_sample_first_quadrant(float n_x,
float n_y,
float randu,
@@ -146,81 +135,84 @@ ccl_device int bsdf_ashikhmin_shirley_sample(ccl_private const ShaderClosure *sc
int label = LABEL_REFLECT | LABEL_GLOSSY;
float NdotI = dot(N, I);
- if (NdotI > 0.0f) {
+ if (!(NdotI > 0.0f)) {
+ *pdf = 0.0f;
+ *eval = zero_spectrum();
+ return LABEL_NONE;
+ }
- float n_x = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_x);
- float n_y = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_y);
+ float n_x = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_x);
+ float n_y = bsdf_ashikhmin_shirley_roughness_to_exponent(bsdf->alpha_y);
- /* get x,y basis on the surface for anisotropy */
- float3 X, Y;
+ /* get x,y basis on the surface for anisotropy */
+ float3 X, Y;
+
+ if (n_x == n_y)
+ make_orthonormals(N, &X, &Y);
+ else
+ make_orthonormals_tangent(N, bsdf->T, &X, &Y);
- if (n_x == n_y)
- make_orthonormals(N, &X, &Y);
- else
- make_orthonormals_tangent(N, bsdf->T, &X, &Y);
-
- /* sample spherical coords for h in tangent space */
- float phi;
- float cos_theta;
- if (n_x == n_y) {
- /* isotropic sampling */
- phi = M_2PI_F * randu;
- cos_theta = powf(randv, 1.0f / (n_x + 1.0f));
+ /* sample spherical coords for h in tangent space */
+ float phi;
+ float cos_theta;
+ if (n_x == n_y) {
+ /* isotropic sampling */
+ phi = M_2PI_F * randu;
+ cos_theta = powf(randv, 1.0f / (n_x + 1.0f));
+ }
+ else {
+ /* anisotropic sampling */
+ if (randu < 0.25f) { /* first quadrant */
+ float remapped_randu = 4.0f * randu;
+ bsdf_ashikhmin_shirley_sample_first_quadrant(
+ n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
}
- else {
- /* anisotropic sampling */
- if (randu < 0.25f) { /* first quadrant */
- float remapped_randu = 4.0f * randu;
- bsdf_ashikhmin_shirley_sample_first_quadrant(
- n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
- }
- else if (randu < 0.5f) { /* second quadrant */
- float remapped_randu = 4.0f * (.5f - randu);
- bsdf_ashikhmin_shirley_sample_first_quadrant(
- n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
- phi = M_PI_F - phi;
- }
- else if (randu < 0.75f) { /* third quadrant */
- float remapped_randu = 4.0f * (randu - 0.5f);
- bsdf_ashikhmin_shirley_sample_first_quadrant(
- n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
- phi = M_PI_F + phi;
- }
- else { /* fourth quadrant */
- float remapped_randu = 4.0f * (1.0f - randu);
- bsdf_ashikhmin_shirley_sample_first_quadrant(
- n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
- phi = 2.0f * M_PI_F - phi;
- }
+ else if (randu < 0.5f) { /* second quadrant */
+ float remapped_randu = 4.0f * (.5f - randu);
+ bsdf_ashikhmin_shirley_sample_first_quadrant(
+ n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
+ phi = M_PI_F - phi;
}
-
- /* get half vector in tangent space */
- float sin_theta = sqrtf(fmaxf(0.0f, 1.0f - cos_theta * cos_theta));
- float cos_phi = cosf(phi);
- float sin_phi = sinf(phi); /* no sqrt(1-cos^2) here b/c it causes artifacts */
- float3 h = make_float3(sin_theta * cos_phi, sin_theta * sin_phi, cos_theta);
-
- /* half vector to world space */
- float3 H = h.x * X + h.y * Y + h.z * N;
- float HdotI = dot(H, I);
- if (HdotI < 0.0f)
- H = -H;
-
- /* reflect I on H to get omega_in */
- *omega_in = -I + (2.0f * HdotI) * H;
-
- if (fmaxf(bsdf->alpha_x, bsdf->alpha_y) <= 1e-4f) {
- /* Some high number for MIS. */
- *pdf = 1e6f;
- *eval = make_spectrum(1e6f);
- label = LABEL_REFLECT | LABEL_SINGULAR;
+ else if (randu < 0.75f) { /* third quadrant */
+ float remapped_randu = 4.0f * (randu - 0.5f);
+ bsdf_ashikhmin_shirley_sample_first_quadrant(
+ n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
+ phi = M_PI_F + phi;
}
- else {
- /* leave the rest to eval_reflect */
- *eval = bsdf_ashikhmin_shirley_eval_reflect(sc, I, *omega_in, pdf);
+ else { /* fourth quadrant */
+ float remapped_randu = 4.0f * (1.0f - randu);
+ bsdf_ashikhmin_shirley_sample_first_quadrant(
+ n_x, n_y, remapped_randu, randv, &phi, &cos_theta);
+ phi = 2.0f * M_PI_F - phi;
}
}
+ /* get half vector in tangent space */
+ float sin_theta = sqrtf(fmaxf(0.0f, 1.0f - cos_theta * cos_theta));
+ float cos_phi = cosf(phi);
+ float sin_phi = sinf(phi); /* no sqrt(1-cos^2) here b/c it causes artifacts */
+ float3 h = make_float3(sin_theta * cos_phi, sin_theta * sin_phi, cos_theta);
+
+ /* half vector to world space */
+ float3 H = h.x * X + h.y * Y + h.z * N;
+ float HdotI = dot(H, I);
+ if (HdotI < 0.0f)
+ H = -H;
+
+ /* reflect I on H to get omega_in */
+ *omega_in = -I + (2.0f * HdotI) * H;
+
+ if (fmaxf(bsdf->alpha_x, bsdf->alpha_y) <= 1e-4f) {
+ /* Some high number for MIS. */
+ *pdf = 1e6f;
+ *eval = make_spectrum(1e6f);
+ label = LABEL_REFLECT | LABEL_SINGULAR;
+ }
+ else {
+ /* leave the rest to eval */
+ *eval = bsdf_ashikhmin_shirley_eval(sc, I, *omega_in, pdf);
+ }
+
return label;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-05 08:39:05 +0300