diff options
author | Brecht Van Lommel <brecht@blender.org> | 2022-09-22 21:03:24 +0300 |
---|---|---|
committer | Brecht Van Lommel <brecht@blender.org> | 2022-09-27 16:56:28 +0300 |
commit | 6d19da0b2d468f099e0c1f56392ab8a1750d114f (patch) | |
tree | 7309b5ef31d5e42dca4e26e13b74bd6f223cba41 /intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h | |
parent | bd249eb4f37e65b2f4b3deef775bb136a2c234d1 (diff) |
Cycles: BSDF eval refactor to remove separate reflection/refraction methods
Simplifies code overall to do it inside the eval function, most of the BSDFs
already compute the dot product.
The refactoring in bsdf_principled_hair_eval() was needed to avoid a HIP
compiler bug. Cause is unclear, just changing the implementation enough
is meant to sidestep it.
Ref T92571, D15286
Diffstat (limited to 'intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h')
-rw-r--r-- | intern/cycles/kernel/closure/bsdf_ashikhmin_shirley.h | 240 |
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; } |