diff options
Diffstat (limited to 'intern/cycles/kernel/closure/bsdf_microfacet.h')
| -rw-r--r-- | intern/cycles/kernel/closure/bsdf_microfacet.h | 1847 |
1 files changed, 957 insertions, 890 deletions
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet.h b/intern/cycles/kernel/closure/bsdf_microfacet.h index 32b6e50b09a..b4da3123f28 100644 --- a/intern/cycles/kernel/closure/bsdf_microfacet.h +++ b/intern/cycles/kernel/closure/bsdf_microfacet.h @@ -36,95 +36,98 @@ CCL_NAMESPACE_BEGIN typedef ccl_addr_space struct MicrofacetExtra { - float3 color, cspec0; - float clearcoat; + float3 color, cspec0; + float clearcoat; } MicrofacetExtra; typedef ccl_addr_space struct MicrofacetBsdf { - SHADER_CLOSURE_BASE; + SHADER_CLOSURE_BASE; - float alpha_x, alpha_y, ior; - MicrofacetExtra *extra; - float3 T; + float alpha_x, alpha_y, ior; + MicrofacetExtra *extra; + float3 T; } MicrofacetBsdf; /* Beckmann and GGX microfacet importance sampling. */ -ccl_device_inline void microfacet_beckmann_sample_slopes( - KernelGlobals *kg, - const float cos_theta_i, const float sin_theta_i, - float randu, float randv, float *slope_x, float *slope_y, - float *G1i) +ccl_device_inline void microfacet_beckmann_sample_slopes(KernelGlobals *kg, + const float cos_theta_i, + const float sin_theta_i, + float randu, + float randv, + float *slope_x, + float *slope_y, + float *G1i) { - /* special case (normal incidence) */ - if(cos_theta_i >= 0.99999f) { - const float r = sqrtf(-logf(randu)); - const float phi = M_2PI_F * randv; - *slope_x = r * cosf(phi); - *slope_y = r * sinf(phi); - *G1i = 1.0f; - return; - } - - /* precomputations */ - const float tan_theta_i = sin_theta_i/cos_theta_i; - const float inv_a = tan_theta_i; - const float cot_theta_i = 1.0f/tan_theta_i; - const float erf_a = fast_erff(cot_theta_i); - const float exp_a2 = expf(-cot_theta_i*cot_theta_i); - const float SQRT_PI_INV = 0.56418958354f; - const float Lambda = 0.5f*(erf_a - 1.0f) + (0.5f*SQRT_PI_INV)*(exp_a2*inv_a); - const float G1 = 1.0f/(1.0f + Lambda); /* masking */ - - *G1i = G1; + /* special case (normal incidence) */ + if (cos_theta_i >= 0.99999f) { + const float r = sqrtf(-logf(randu)); + const float phi = M_2PI_F * randv; + *slope_x = r * cosf(phi); + *slope_y = r * sinf(phi); + *G1i = 1.0f; + return; + } + + /* precomputations */ + const float tan_theta_i = sin_theta_i / cos_theta_i; + const float inv_a = tan_theta_i; + const float cot_theta_i = 1.0f / tan_theta_i; + const float erf_a = fast_erff(cot_theta_i); + const float exp_a2 = expf(-cot_theta_i * cot_theta_i); + const float SQRT_PI_INV = 0.56418958354f; + const float Lambda = 0.5f * (erf_a - 1.0f) + (0.5f * SQRT_PI_INV) * (exp_a2 * inv_a); + const float G1 = 1.0f / (1.0f + Lambda); /* masking */ + + *G1i = G1; #if defined(__KERNEL_GPU__) - /* Based on paper from Wenzel Jakob - * An Improved Visible Normal Sampling Routine for the Beckmann Distribution - * - * http://www.mitsuba-renderer.org/~wenzel/files/visnormal.pdf - * - * Reformulation from OpenShadingLanguage which avoids using inverse - * trigonometric functions. - */ - - /* Sample slope X. - * - * Compute a coarse approximation using the approximation: - * exp(-ierf(x)^2) ~= 1 - x * x - * solve y = 1 + b + K * (1 - b * b) - */ - float K = tan_theta_i * SQRT_PI_INV; - float y_approx = randu * (1.0f + erf_a + K * (1 - erf_a * erf_a)); - float y_exact = randu * (1.0f + erf_a + K * exp_a2); - float b = K > 0 ? (0.5f - sqrtf(K * (K - y_approx + 1.0f) + 0.25f)) / K : y_approx - 1.0f; - - /* Perform newton step to refine toward the true root. */ - float inv_erf = fast_ierff(b); - float value = 1.0f + b + K * expf(-inv_erf * inv_erf) - y_exact; - /* Check if we are close enough already, - * this also avoids NaNs as we get close to the root. - */ - if(fabsf(value) > 1e-6f) { - b -= value / (1.0f - inv_erf * tan_theta_i); /* newton step 1. */ - inv_erf = fast_ierff(b); - value = 1.0f + b + K * expf(-inv_erf * inv_erf) - y_exact; - b -= value / (1.0f - inv_erf * tan_theta_i); /* newton step 2. */ - /* Compute the slope from the refined value. */ - *slope_x = fast_ierff(b); - } - else { - /* We are close enough already. */ - *slope_x = inv_erf; - } - *slope_y = fast_ierff(2.0f*randv - 1.0f); + /* Based on paper from Wenzel Jakob + * An Improved Visible Normal Sampling Routine for the Beckmann Distribution + * + * http://www.mitsuba-renderer.org/~wenzel/files/visnormal.pdf + * + * Reformulation from OpenShadingLanguage which avoids using inverse + * trigonometric functions. + */ + + /* Sample slope X. + * + * Compute a coarse approximation using the approximation: + * exp(-ierf(x)^2) ~= 1 - x * x + * solve y = 1 + b + K * (1 - b * b) + */ + float K = tan_theta_i * SQRT_PI_INV; + float y_approx = randu * (1.0f + erf_a + K * (1 - erf_a * erf_a)); + float y_exact = randu * (1.0f + erf_a + K * exp_a2); + float b = K > 0 ? (0.5f - sqrtf(K * (K - y_approx + 1.0f) + 0.25f)) / K : y_approx - 1.0f; + + /* Perform newton step to refine toward the true root. */ + float inv_erf = fast_ierff(b); + float value = 1.0f + b + K * expf(-inv_erf * inv_erf) - y_exact; + /* Check if we are close enough already, + * this also avoids NaNs as we get close to the root. + */ + if (fabsf(value) > 1e-6f) { + b -= value / (1.0f - inv_erf * tan_theta_i); /* newton step 1. */ + inv_erf = fast_ierff(b); + value = 1.0f + b + K * expf(-inv_erf * inv_erf) - y_exact; + b -= value / (1.0f - inv_erf * tan_theta_i); /* newton step 2. */ + /* Compute the slope from the refined value. */ + *slope_x = fast_ierff(b); + } + else { + /* We are close enough already. */ + *slope_x = inv_erf; + } + *slope_y = fast_ierff(2.0f * randv - 1.0f); #else - /* Use precomputed table on CPU, it gives better perfomance. */ - int beckmann_table_offset = kernel_data.tables.beckmann_offset; + /* Use precomputed table on CPU, it gives better perfomance. */ + int beckmann_table_offset = kernel_data.tables.beckmann_offset; - *slope_x = lookup_table_read_2D(kg, randu, cos_theta_i, - beckmann_table_offset, BECKMANN_TABLE_SIZE, BECKMANN_TABLE_SIZE); - *slope_y = fast_ierff(2.0f*randv - 1.0f); + *slope_x = lookup_table_read_2D( + kg, randu, cos_theta_i, beckmann_table_offset, BECKMANN_TABLE_SIZE, BECKMANN_TABLE_SIZE); + *slope_y = fast_ierff(2.0f * randv - 1.0f); #endif } @@ -134,103 +137,109 @@ ccl_device_inline void microfacet_beckmann_sample_slopes( * E. Heitz and E. d'Eon, EGSR 2014 */ -ccl_device_inline void microfacet_ggx_sample_slopes( - const float cos_theta_i, const float sin_theta_i, - float randu, float randv, float *slope_x, float *slope_y, - float *G1i) +ccl_device_inline void microfacet_ggx_sample_slopes(const float cos_theta_i, + const float sin_theta_i, + float randu, + float randv, + float *slope_x, + float *slope_y, + float *G1i) { - /* special case (normal incidence) */ - if(cos_theta_i >= 0.99999f) { - const float r = sqrtf(randu/(1.0f - randu)); - const float phi = M_2PI_F * randv; - *slope_x = r * cosf(phi); - *slope_y = r * sinf(phi); - *G1i = 1.0f; - - return; - } - - /* precomputations */ - const float tan_theta_i = sin_theta_i/cos_theta_i; - const float G1_inv = 0.5f * (1.0f + safe_sqrtf(1.0f + tan_theta_i*tan_theta_i)); - - *G1i = 1.0f/G1_inv; - - /* sample slope_x */ - const float A = 2.0f*randu*G1_inv - 1.0f; - const float AA = A*A; - const float tmp = 1.0f/(AA - 1.0f); - const float B = tan_theta_i; - const float BB = B*B; - const float D = safe_sqrtf(BB*(tmp*tmp) - (AA - BB)*tmp); - const float slope_x_1 = B*tmp - D; - const float slope_x_2 = B*tmp + D; - *slope_x = (A < 0.0f || slope_x_2*tan_theta_i > 1.0f)? slope_x_1: slope_x_2; - - /* sample slope_y */ - float S; - - if(randv > 0.5f) { - S = 1.0f; - randv = 2.0f*(randv - 0.5f); - } - else { - S = -1.0f; - randv = 2.0f*(0.5f - randv); - } - - const float z = (randv*(randv*(randv*0.27385f - 0.73369f) + 0.46341f)) / (randv*(randv*(randv*0.093073f + 0.309420f) - 1.000000f) + 0.597999f); - *slope_y = S * z * safe_sqrtf(1.0f + (*slope_x)*(*slope_x)); + /* special case (normal incidence) */ + if (cos_theta_i >= 0.99999f) { + const float r = sqrtf(randu / (1.0f - randu)); + const float phi = M_2PI_F * randv; + *slope_x = r * cosf(phi); + *slope_y = r * sinf(phi); + *G1i = 1.0f; + + return; + } + + /* precomputations */ + const float tan_theta_i = sin_theta_i / cos_theta_i; + const float G1_inv = 0.5f * (1.0f + safe_sqrtf(1.0f + tan_theta_i * tan_theta_i)); + + *G1i = 1.0f / G1_inv; + + /* sample slope_x */ + const float A = 2.0f * randu * G1_inv - 1.0f; + const float AA = A * A; + const float tmp = 1.0f / (AA - 1.0f); + const float B = tan_theta_i; + const float BB = B * B; + const float D = safe_sqrtf(BB * (tmp * tmp) - (AA - BB) * tmp); + const float slope_x_1 = B * tmp - D; + const float slope_x_2 = B * tmp + D; + *slope_x = (A < 0.0f || slope_x_2 * tan_theta_i > 1.0f) ? slope_x_1 : slope_x_2; + + /* sample slope_y */ + float S; + + if (randv > 0.5f) { + S = 1.0f; + randv = 2.0f * (randv - 0.5f); + } + else { + S = -1.0f; + randv = 2.0f * (0.5f - randv); + } + + const float z = (randv * (randv * (randv * 0.27385f - 0.73369f) + 0.46341f)) / + (randv * (randv * (randv * 0.093073f + 0.309420f) - 1.000000f) + 0.597999f); + *slope_y = S * z * safe_sqrtf(1.0f + (*slope_x) * (*slope_x)); } -ccl_device_forceinline float3 microfacet_sample_stretched( - KernelGlobals *kg, const float3 omega_i, - const float alpha_x, const float alpha_y, - const float randu, const float randv, - bool beckmann, float *G1i) +ccl_device_forceinline float3 microfacet_sample_stretched(KernelGlobals *kg, + const float3 omega_i, + const float alpha_x, + const float alpha_y, + const float randu, + const float randv, + bool beckmann, + float *G1i) { - /* 1. stretch omega_i */ - float3 omega_i_ = make_float3(alpha_x * omega_i.x, alpha_y * omega_i.y, omega_i.z); - omega_i_ = normalize(omega_i_); - - /* get polar coordinates of omega_i_ */ - float costheta_ = 1.0f; - float sintheta_ = 0.0f; - float cosphi_ = 1.0f; - float sinphi_ = 0.0f; - - if(omega_i_.z < 0.99999f) { - costheta_ = omega_i_.z; - sintheta_ = safe_sqrtf(1.0f - costheta_*costheta_); - - float invlen = 1.0f/sintheta_; - cosphi_ = omega_i_.x * invlen; - sinphi_ = omega_i_.y * invlen; - } - - /* 2. sample P22_{omega_i}(x_slope, y_slope, 1, 1) */ - float slope_x, slope_y; - - if(beckmann) { - microfacet_beckmann_sample_slopes(kg, costheta_, sintheta_, - randu, randv, &slope_x, &slope_y, G1i); - } - else { - microfacet_ggx_sample_slopes(costheta_, sintheta_, - randu, randv, &slope_x, &slope_y, G1i); - } - - /* 3. rotate */ - float tmp = cosphi_*slope_x - sinphi_*slope_y; - slope_y = sinphi_*slope_x + cosphi_*slope_y; - slope_x = tmp; - - /* 4. unstretch */ - slope_x = alpha_x * slope_x; - slope_y = alpha_y * slope_y; - - /* 5. compute normal */ - return normalize(make_float3(-slope_x, -slope_y, 1.0f)); + /* 1. stretch omega_i */ + float3 omega_i_ = make_float3(alpha_x * omega_i.x, alpha_y * omega_i.y, omega_i.z); + omega_i_ = normalize(omega_i_); + + /* get polar coordinates of omega_i_ */ + float costheta_ = 1.0f; + float sintheta_ = 0.0f; + float cosphi_ = 1.0f; + float sinphi_ = 0.0f; + + if (omega_i_.z < 0.99999f) { + costheta_ = omega_i_.z; + sintheta_ = safe_sqrtf(1.0f - costheta_ * costheta_); + + float invlen = 1.0f / sintheta_; + cosphi_ = omega_i_.x * invlen; + sinphi_ = omega_i_.y * invlen; + } + + /* 2. sample P22_{omega_i}(x_slope, y_slope, 1, 1) */ + float slope_x, slope_y; + + if (beckmann) { + microfacet_beckmann_sample_slopes( + kg, costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i); + } + else { + microfacet_ggx_sample_slopes(costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i); + } + + /* 3. rotate */ + float tmp = cosphi_ * slope_x - sinphi_ * slope_y; + slope_y = sinphi_ * slope_x + cosphi_ * slope_y; + slope_x = tmp; + + /* 4. unstretch */ + slope_x = alpha_x * slope_x; + slope_y = alpha_y * slope_y; + + /* 5. compute normal */ + return normalize(make_float3(-slope_x, -slope_y, 1.0f)); } /* Calculate the reflection color @@ -240,27 +249,29 @@ ccl_device_forceinline float3 microfacet_sample_stretched( * * 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); - bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID - || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID - || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID); +ccl_device_forceinline float3 reflection_color(const MicrofacetBsdf *bsdf, float3 L, float3 H) +{ + float3 F = make_float3(1.0f, 1.0f, 1.0f); + bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID || + bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID || + bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID); - if(use_fresnel) { - float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); + if (use_fresnel) { + float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); - F = interpolate_fresnel_color(L, H, bsdf->ior, F0, bsdf->extra->cspec0); - } + F = interpolate_fresnel_color(L, H, bsdf->ior, F0, bsdf->extra->cspec0); + } - return F; + return F; } ccl_device_forceinline float D_GTR1(float NdotH, float alpha) { - if(alpha >= 1.0f) return M_1_PI_F; - float alpha2 = alpha*alpha; - float t = 1.0f + (alpha2 - 1.0f) * NdotH*NdotH; - return (alpha2 - 1.0f) / (M_PI_F * logf(alpha2) * t); + if (alpha >= 1.0f) + return M_1_PI_F; + float alpha2 = alpha * alpha; + float t = 1.0f + (alpha2 - 1.0f) * NdotH * NdotH; + return (alpha2 - 1.0f) / (M_PI_F * logf(alpha2) * t); } /* GGX microfacet with Smith shadow-masking from: @@ -278,483 +289,511 @@ ccl_device_forceinline float D_GTR1(float NdotH, float alpha) ccl_device int bsdf_microfacet_ggx_setup(MicrofacetBsdf *bsdf) { - bsdf->extra = NULL; + bsdf->extra = NULL; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_ggx_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd) { - bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); - bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); - bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); + bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); + bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); + bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); - float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); - float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); - bsdf->sample_weight *= F; + float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); + float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); + bsdf->sample_weight *= F; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_ggx_clearcoat_setup(MicrofacetBsdf *bsdf, const ShaderData *sd) { - bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); - bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); - bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); + bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); + bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); + bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); - float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); - float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); - bsdf->sample_weight *= 0.25f * bsdf->extra->clearcoat * F; + float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); + float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); + bsdf->sample_weight *= 0.25f * bsdf->extra->clearcoat * F; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device bool bsdf_microfacet_merge(const ShaderClosure *a, const ShaderClosure *b) { - const MicrofacetBsdf *bsdf_a = (const MicrofacetBsdf*)a; - const MicrofacetBsdf *bsdf_b = (const MicrofacetBsdf*)b; - - return (isequal_float3(bsdf_a->N, bsdf_b->N)) && - (bsdf_a->alpha_x == bsdf_b->alpha_x) && - (bsdf_a->alpha_y == bsdf_b->alpha_y) && - (isequal_float3(bsdf_a->T, bsdf_b->T)) && - (bsdf_a->ior == bsdf_b->ior) && - ((bsdf_a->extra == NULL && bsdf_b->extra == NULL) || - ((bsdf_a->extra && bsdf_b->extra) && - (isequal_float3(bsdf_a->extra->color, bsdf_b->extra->color)) && - (isequal_float3(bsdf_a->extra->cspec0, bsdf_b->extra->cspec0)) && - (bsdf_a->extra->clearcoat == bsdf_b->extra->clearcoat))); + const MicrofacetBsdf *bsdf_a = (const MicrofacetBsdf *)a; + const MicrofacetBsdf *bsdf_b = (const MicrofacetBsdf *)b; + + return (isequal_float3(bsdf_a->N, bsdf_b->N)) && (bsdf_a->alpha_x == bsdf_b->alpha_x) && + (bsdf_a->alpha_y == bsdf_b->alpha_y) && (isequal_float3(bsdf_a->T, bsdf_b->T)) && + (bsdf_a->ior == bsdf_b->ior) && + ((bsdf_a->extra == NULL && bsdf_b->extra == NULL) || + ((bsdf_a->extra && bsdf_b->extra) && + (isequal_float3(bsdf_a->extra->color, bsdf_b->extra->color)) && + (isequal_float3(bsdf_a->extra->cspec0, bsdf_b->extra->cspec0)) && + (bsdf_a->extra->clearcoat == bsdf_b->extra->clearcoat))); } ccl_device int bsdf_microfacet_ggx_aniso_setup(MicrofacetBsdf *bsdf) { - bsdf->extra = NULL; + bsdf->extra = NULL; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = saturate(bsdf->alpha_y); + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = saturate(bsdf->alpha_y); - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsdf, const ShaderData *sd) { - bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); - bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); - bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); + bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x); + bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y); + bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z); - float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); - float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); - bsdf->sample_weight *= F; + float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior); + float F = average(interpolate_fresnel_color(sd->I, bsdf->N, bsdf->ior, F0, bsdf->extra->cspec0)); + bsdf->sample_weight *= F; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = saturate(bsdf->alpha_y); + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = saturate(bsdf->alpha_y); - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_ggx_refraction_setup(MicrofacetBsdf *bsdf) { - bsdf->extra = NULL; + bsdf->extra = NULL; - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; + bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device void bsdf_microfacet_ggx_blur(ShaderClosure *sc, float roughness) { - MicrofacetBsdf *bsdf = (MicrofacetBsdf*)sc; + MicrofacetBsdf *bsdf = (MicrofacetBsdf *)sc; - bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x); - bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y); + bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x); + bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y); } -ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, + const float3 I, + const float3 omega_in, + float *pdf) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; - float3 N = bsdf->N; - - if(m_refractive || alpha_x*alpha_y <= 1e-7f) - return make_float3(0.0f, 0.0f, 0.0f); - - float cosNO = dot(N, I); - float cosNI = dot(N, omega_in); - - if(cosNI > 0 && cosNO > 0) { - /* get half vector */ - float3 m = normalize(omega_in + I); - float alpha2 = alpha_x * alpha_y; - float D, G1o, G1i; - - if(alpha_x == alpha_y) { - /* isotropic - * eq. 20: (F*G*D)/(4*in*on) - * eq. 33: first we calculate D(m) */ - float cosThetaM = dot(N, m); - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; - - if(bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { - /* use GTR1 for clearcoat */ - D = D_GTR1(cosThetaM, bsdf->alpha_x); - - /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */ - alpha2 = 0.0625f; - } - else { - /* use GTR2 otherwise */ - D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); - } - - /* 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))); - } - else { - /* anisotropic */ - float3 X, Y, Z = N; - make_orthonormals_tangent(Z, bsdf->T, &X, &Y); - - /* distribution */ - float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); - float slope_x = -local_m.x/(local_m.z*alpha_x); - float slope_y = -local_m.y/(local_m.z*alpha_y); - float slope_len = 1 + slope_x*slope_x + slope_y*slope_y; - - float cosThetaM = local_m.z; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - - D = 1 / ((slope_len * slope_len) * M_PI_F * alpha2 * cosThetaM4); - - /* G1(i,m) and G1(o,m) */ - float tanThetaO2 = (1 - cosNO * cosNO) / (cosNO * cosNO); - float cosPhiO = dot(I, X); - float sinPhiO = dot(I, Y); - - float alphaO2 = (cosPhiO*cosPhiO)*(alpha_x*alpha_x) + (sinPhiO*sinPhiO)*(alpha_y*alpha_y); - alphaO2 /= cosPhiO*cosPhiO + sinPhiO*sinPhiO; - - G1o = 2 / (1 + safe_sqrtf(1 + alphaO2 * tanThetaO2)); - - float tanThetaI2 = (1 - cosNI * cosNI) / (cosNI * cosNI); - float cosPhiI = dot(omega_in, X); - float sinPhiI = dot(omega_in, Y); - - float alphaI2 = (cosPhiI*cosPhiI)*(alpha_x*alpha_x) + (sinPhiI*sinPhiI)*(alpha_y*alpha_y); - alphaI2 /= cosPhiI*cosPhiI + sinPhiI*sinPhiI; - - G1i = 2 / (1 + safe_sqrtf(1 + alphaI2 * tanThetaI2)); - } - - float G = G1o * G1i; - - /* eq. 20 */ - float common = D * 0.25f / cosNO; - - float3 F = reflection_color(bsdf, omega_in, m); - if(bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { - F *= 0.25f * bsdf->extra->clearcoat; - } - - float3 out = F * G * common; - - /* eq. 2 in distribution of visible normals sampling - * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ - - /* eq. 38 - but see also: - * eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf - * pdf = pm * 0.25 / dot(m, I); */ - *pdf = G1o * common; - - return out; - } - - return make_float3(0.0f, 0.0f, 0.0f); + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; + float3 N = bsdf->N; + + if (m_refractive || alpha_x * alpha_y <= 1e-7f) + return make_float3(0.0f, 0.0f, 0.0f); + + float cosNO = dot(N, I); + float cosNI = dot(N, omega_in); + + if (cosNI > 0 && cosNO > 0) { + /* get half vector */ + float3 m = normalize(omega_in + I); + float alpha2 = alpha_x * alpha_y; + float D, G1o, G1i; + + if (alpha_x == alpha_y) { + /* isotropic + * eq. 20: (F*G*D)/(4*in*on) + * eq. 33: first we calculate D(m) */ + float cosThetaM = dot(N, m); + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; + + if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { + /* use GTR1 for clearcoat */ + D = D_GTR1(cosThetaM, bsdf->alpha_x); + + /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */ + alpha2 = 0.0625f; + } + else { + /* use GTR2 otherwise */ + D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); + } + + /* 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))); + } + else { + /* anisotropic */ + float3 X, Y, Z = N; + make_orthonormals_tangent(Z, bsdf->T, &X, &Y); + + /* distribution */ + float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); + float slope_x = -local_m.x / (local_m.z * alpha_x); + float slope_y = -local_m.y / (local_m.z * alpha_y); + float slope_len = 1 + slope_x * slope_x + slope_y * slope_y; + + float cosThetaM = local_m.z; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + + D = 1 / ((slope_len * slope_len) * M_PI_F * alpha2 * cosThetaM4); + + /* G1(i,m) and G1(o,m) */ + float tanThetaO2 = (1 - cosNO * cosNO) / (cosNO * cosNO); + float cosPhiO = dot(I, X); + float sinPhiO = dot(I, Y); + + float alphaO2 = (cosPhiO * cosPhiO) * (alpha_x * alpha_x) + + (sinPhiO * sinPhiO) * (alpha_y * alpha_y); + alphaO2 /= cosPhiO * cosPhiO + sinPhiO * sinPhiO; + + G1o = 2 / (1 + safe_sqrtf(1 + alphaO2 * tanThetaO2)); + + float tanThetaI2 = (1 - cosNI * cosNI) / (cosNI * cosNI); + float cosPhiI = dot(omega_in, X); + float sinPhiI = dot(omega_in, Y); + + float alphaI2 = (cosPhiI * cosPhiI) * (alpha_x * alpha_x) + + (sinPhiI * sinPhiI) * (alpha_y * alpha_y); + alphaI2 /= cosPhiI * cosPhiI + sinPhiI * sinPhiI; + + G1i = 2 / (1 + safe_sqrtf(1 + alphaI2 * tanThetaI2)); + } + + float G = G1o * G1i; + + /* eq. 20 */ + float common = D * 0.25f / cosNO; + + float3 F = reflection_color(bsdf, omega_in, m); + if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { + F *= 0.25f * bsdf->extra->clearcoat; + } + + float3 out = F * G * common; + + /* eq. 2 in distribution of visible normals sampling + * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ + + /* eq. 38 - but see also: + * eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf + * pdf = pm * 0.25 / dot(m, I); */ + *pdf = G1o * common; + + return out; + } + + return make_float3(0.0f, 0.0f, 0.0f); } -ccl_device float3 bsdf_microfacet_ggx_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +ccl_device float3 bsdf_microfacet_ggx_eval_transmit(const ShaderClosure *sc, + const float3 I, + const float3 omega_in, + float *pdf) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - float m_eta = bsdf->ior; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; - float3 N = bsdf->N; + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + float m_eta = bsdf->ior; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; + float3 N = bsdf->N; - if(!m_refractive || alpha_x*alpha_y <= 1e-7f) - return make_float3(0.0f, 0.0f, 0.0f); + if (!m_refractive || alpha_x * alpha_y <= 1e-7f) + return make_float3(0.0f, 0.0f, 0.0f); - float cosNO = dot(N, I); - float cosNI = dot(N, omega_in); + float cosNO = dot(N, I); + float cosNI = dot(N, omega_in); - if(cosNO <= 0 || cosNI >= 0) - return make_float3(0.0f, 0.0f, 0.0f); /* vectors on same side -- not possible */ + if (cosNO <= 0 || cosNI >= 0) + return make_float3(0.0f, 0.0f, 0.0f); /* vectors on same side -- not possible */ - /* compute half-vector of the refraction (eq. 16) */ - float3 ht = -(m_eta * omega_in + I); - float3 Ht = normalize(ht); - float cosHO = dot(Ht, I); - float cosHI = dot(Ht, omega_in); + /* compute half-vector of the refraction (eq. 16) */ + float3 ht = -(m_eta * omega_in + I); + float3 Ht = normalize(ht); + float cosHO = dot(Ht, I); + float cosHI = dot(Ht, omega_in); - float D, G1o, G1i; + float D, G1o, G1i; - /* eq. 33: first we calculate D(m) with m=Ht: */ - float alpha2 = alpha_x * alpha_y; - float cosThetaM = dot(N, Ht); - float cosThetaM2 = cosThetaM * cosThetaM; - float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); + /* eq. 33: first we calculate D(m) with m=Ht: */ + float alpha2 = alpha_x * alpha_y; + float cosThetaM = dot(N, Ht); + float cosThetaM2 = cosThetaM * cosThetaM; + float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); - /* 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))); + /* 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))); - float G = G1o * G1i; + float G = G1o * G1i; - /* probability */ - float Ht2 = dot(ht, ht); + /* probability */ + float Ht2 = dot(ht, ht); - /* eq. 2 in distribution of visible normals sampling - * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ + /* eq. 2 in distribution of visible normals sampling + * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ - /* out = fabsf(cosHI * cosHO) * (m_eta * m_eta) * G * D / (cosNO * Ht2) - * pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2 */ - float common = D * (m_eta * m_eta) / (cosNO * Ht2); - float out = G * fabsf(cosHI * cosHO) * common; - *pdf = G1o * fabsf(cosHO * cosHI) * common; + /* out = fabsf(cosHI * cosHO) * (m_eta * m_eta) * G * D / (cosNO * Ht2) + * pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2 */ + float common = D * (m_eta * m_eta) / (cosNO * Ht2); + float out = G * fabsf(cosHI * cosHO) * common; + *pdf = G1o * fabsf(cosHO * cosHI) * common; - return make_float3(out, out, 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) +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) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; - float3 N = bsdf->N; - int label; - - float cosNO = dot(N, I); - if(cosNO > 0) { - float3 X, Y, Z = N; - - if(alpha_x == alpha_y) - make_orthonormals(Z, &X, &Y); - else - make_orthonormals_tangent(Z, bsdf->T, &X, &Y); - - /* importance sampling with distribution of visible normals. vectors are - * transformed to local space before and after */ - float3 local_I = make_float3(dot(X, I), dot(Y, I), cosNO); - float3 local_m; - float G1o; - - local_m = microfacet_sample_stretched(kg, local_I, alpha_x, alpha_y, - randu, randv, false, &G1o); - - float3 m = X*local_m.x + Y*local_m.y + Z*local_m.z; - float cosThetaM = local_m.z; - - /* reflection or refraction? */ - if(!m_refractive) { - float cosMO = dot(m, I); - label = LABEL_REFLECT | LABEL_GLOSSY; - - if(cosMO > 0) { - /* eq. 39 - compute actual reflected direction */ - *omega_in = 2 * cosMO * m - I; - - if(dot(Ng, *omega_in) > 0) { - if(alpha_x*alpha_y <= 1e-7f) { - /* some high number for MIS */ - *pdf = 1e6f; - *eval = make_float3(1e6f, 1e6f, 1e6f); - - bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID - || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID - || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID); - - /* if fresnel is used, calculate the color with reflection_color(...) */ - if(use_fresnel) { - *eval *= reflection_color(bsdf, *omega_in, m); - } - - label = LABEL_REFLECT | LABEL_SINGULAR; - } - else { - /* microfacet normal is visible to this ray */ - /* eq. 33 */ - float alpha2 = alpha_x * alpha_y; - float D, G1i; - - if(alpha_x == alpha_y) { - /* isotropic */ - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float tanThetaM2 = 1/(cosThetaM2) - 1; - - /* eval BRDF*cosNI */ - float cosNI = dot(N, *omega_in); - - if(bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { - /* use GTR1 for clearcoat */ - D = D_GTR1(cosThetaM, bsdf->alpha_x); - - /* 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))); - } - else { - /* use GTR2 otherwise */ - D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); - } - - /* eq. 34: now calculate G1(i,m) */ - G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI))); - } - else { - /* anisotropic distribution */ - float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); - float slope_x = -local_m.x/(local_m.z*alpha_x); - float slope_y = -local_m.y/(local_m.z*alpha_y); - float slope_len = 1 + slope_x*slope_x + slope_y*slope_y; - - float cosThetaM = local_m.z; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - - D = 1 / ((slope_len * slope_len) * M_PI_F * alpha2 * cosThetaM4); - - /* calculate G1(i,m) */ - float cosNI = dot(N, *omega_in); - - float tanThetaI2 = (1 - cosNI * cosNI) / (cosNI * cosNI); - float cosPhiI = dot(*omega_in, X); - float sinPhiI = dot(*omega_in, Y); - - float alphaI2 = (cosPhiI*cosPhiI)*(alpha_x*alpha_x) + (sinPhiI*sinPhiI)*(alpha_y*alpha_y); - alphaI2 /= cosPhiI*cosPhiI + sinPhiI*sinPhiI; - - G1i = 2 / (1 + safe_sqrtf(1 + alphaI2 * tanThetaI2)); - } - - /* see eval function for derivation */ - float common = (G1o * D) * 0.25f / cosNO; - *pdf = common; - - float3 F = reflection_color(bsdf, *omega_in, m); - - *eval = G1i * common * F; - } - - if(bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { - *eval *= 0.25f * bsdf->extra->clearcoat; - } + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID; + float3 N = bsdf->N; + int label; + + float cosNO = dot(N, I); + if (cosNO > 0) { + float3 X, Y, Z = N; + + if (alpha_x == alpha_y) + make_orthonormals(Z, &X, &Y); + else + make_orthonormals_tangent(Z, bsdf->T, &X, &Y); + + /* importance sampling with distribution of visible normals. vectors are + * transformed to local space before and after */ + float3 local_I = make_float3(dot(X, I), dot(Y, I), cosNO); + float3 local_m; + float G1o; + + local_m = microfacet_sample_stretched( + kg, local_I, alpha_x, alpha_y, randu, randv, false, &G1o); + + float3 m = X * local_m.x + Y * local_m.y + Z * local_m.z; + float cosThetaM = local_m.z; + + /* reflection or refraction? */ + if (!m_refractive) { + float cosMO = dot(m, I); + label = LABEL_REFLECT | LABEL_GLOSSY; + + if (cosMO > 0) { + /* eq. 39 - compute actual reflected direction */ + *omega_in = 2 * cosMO * m - I; + + if (dot(Ng, *omega_in) > 0) { + if (alpha_x * alpha_y <= 1e-7f) { + /* some high number for MIS */ + *pdf = 1e6f; + *eval = make_float3(1e6f, 1e6f, 1e6f); + + bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID || + bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID || + bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID); + + /* if fresnel is used, calculate the color with reflection_color(...) */ + if (use_fresnel) { + *eval *= reflection_color(bsdf, *omega_in, m); + } + + label = LABEL_REFLECT | LABEL_SINGULAR; + } + else { + /* microfacet normal is visible to this ray */ + /* eq. 33 */ + float alpha2 = alpha_x * alpha_y; + float D, G1i; + + if (alpha_x == alpha_y) { + /* isotropic */ + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float tanThetaM2 = 1 / (cosThetaM2)-1; + + /* eval BRDF*cosNI */ + float cosNI = dot(N, *omega_in); + + if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { + /* use GTR1 for clearcoat */ + D = D_GTR1(cosThetaM, bsdf->alpha_x); + + /* 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))); + } + else { + /* use GTR2 otherwise */ + D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); + } + + /* eq. 34: now calculate G1(i,m) */ + G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI))); + } + else { + /* anisotropic distribution */ + float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); + float slope_x = -local_m.x / (local_m.z * alpha_x); + float slope_y = -local_m.y / (local_m.z * alpha_y); + float slope_len = 1 + slope_x * slope_x + slope_y * slope_y; + + float cosThetaM = local_m.z; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + + D = 1 / ((slope_len * slope_len) * M_PI_F * alpha2 * cosThetaM4); + + /* calculate G1(i,m) */ + float cosNI = dot(N, *omega_in); + + float tanThetaI2 = (1 - cosNI * cosNI) / (cosNI * cosNI); + float cosPhiI = dot(*omega_in, X); + float sinPhiI = dot(*omega_in, Y); + + float alphaI2 = (cosPhiI * cosPhiI) * (alpha_x * alpha_x) + + (sinPhiI * sinPhiI) * (alpha_y * alpha_y); + alphaI2 /= cosPhiI * cosPhiI + sinPhiI * sinPhiI; + + G1i = 2 / (1 + safe_sqrtf(1 + alphaI2 * tanThetaI2)); + } + + /* see eval function for derivation */ + float common = (G1o * D) * 0.25f / cosNO; + *pdf = common; + + float3 F = reflection_color(bsdf, *omega_in, m); + + *eval = G1i * common * F; + } + + if (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID) { + *eval *= 0.25f * bsdf->extra->clearcoat; + } #ifdef __RAY_DIFFERENTIALS__ - *domega_in_dx = (2 * dot(m, dIdx)) * m - dIdx; - *domega_in_dy = (2 * dot(m, dIdy)) * m - dIdy; + *domega_in_dx = (2 * dot(m, dIdx)) * m - dIdx; + *domega_in_dy = (2 * dot(m, dIdy)) * m - dIdy; #endif - } - } - } - else { - label = LABEL_TRANSMIT | LABEL_GLOSSY; - - /* CAUTION: the i and o variables are inverted relative to the paper - * eq. 39 - compute actual refractive direction */ - float3 R, T; + } + } + } + else { + label = LABEL_TRANSMIT | LABEL_GLOSSY; + + /* CAUTION: the i and o variables are inverted relative to the paper + * eq. 39 - compute actual refractive direction */ + float3 R, T; #ifdef __RAY_DIFFERENTIALS__ - float3 dRdx, dRdy, dTdx, dTdy; + float3 dRdx, dRdy, dTdx, dTdy; #endif - float m_eta = bsdf->ior, fresnel; - bool inside; - - fresnel = fresnel_dielectric(m_eta, m, I, &R, &T, + float m_eta = bsdf->ior, fresnel; + bool inside; + + fresnel = fresnel_dielectric(m_eta, + m, + I, + &R, + &T, #ifdef __RAY_DIFFERENTIALS__ - dIdx, dIdy, &dRdx, &dRdy, &dTdx, &dTdy, + dIdx, + dIdy, + &dRdx, + &dRdy, + &dTdx, + &dTdy, #endif - &inside); + &inside); - if(!inside && fresnel != 1.0f) { + if (!inside && fresnel != 1.0f) { - *omega_in = T; + *omega_in = T; #ifdef __RAY_DIFFERENTIALS__ - *domega_in_dx = dTdx; - *domega_in_dy = dTdy; + *domega_in_dx = dTdx; + *domega_in_dy = dTdy; #endif - if(alpha_x*alpha_y <= 1e-7f || fabsf(m_eta - 1.0f) < 1e-4f) { - /* some high number for MIS */ - *pdf = 1e6f; - *eval = make_float3(1e6f, 1e6f, 1e6f); - label = LABEL_TRANSMIT | LABEL_SINGULAR; - } - else { - /* eq. 33 */ - float alpha2 = alpha_x * alpha_y; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float tanThetaM2 = 1/(cosThetaM2) - 1; - float D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); - - /* eval BRDF*cosNI */ - float cosNI = dot(N, *omega_in); - - /* eq. 34: now calculate G1(i,m) */ - float G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI))); - - /* eq. 21 */ - float cosHI = dot(m, *omega_in); - float cosHO = dot(m, I); - float Ht2 = m_eta * cosHI + cosHO; - Ht2 *= Ht2; - - /* see eval function for derivation */ - float common = (G1o * D) * (m_eta * m_eta) / (cosNO * Ht2); - float out = G1i * fabsf(cosHI * cosHO) * common; - *pdf = cosHO * fabsf(cosHI) * common; - - *eval = make_float3(out, out, out); - } - } - } - } - else { - label = (m_refractive) ? LABEL_TRANSMIT|LABEL_GLOSSY : LABEL_REFLECT|LABEL_GLOSSY; - } - return label; + if (alpha_x * alpha_y <= 1e-7f || fabsf(m_eta - 1.0f) < 1e-4f) { + /* some high number for MIS */ + *pdf = 1e6f; + *eval = make_float3(1e6f, 1e6f, 1e6f); + label = LABEL_TRANSMIT | LABEL_SINGULAR; + } + else { + /* eq. 33 */ + float alpha2 = alpha_x * alpha_y; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float tanThetaM2 = 1 / (cosThetaM2)-1; + float D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2)); + + /* eval BRDF*cosNI */ + float cosNI = dot(N, *omega_in); + + /* eq. 34: now calculate G1(i,m) */ + float G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI))); + + /* eq. 21 */ + float cosHI = dot(m, *omega_in); + float cosHO = dot(m, I); + float Ht2 = m_eta * cosHI + cosHO; + Ht2 *= Ht2; + + /* see eval function for derivation */ + float common = (G1o * D) * (m_eta * m_eta) / (cosNO * Ht2); + float out = G1i * fabsf(cosHI * cosHO) * common; + *pdf = cosHO * fabsf(cosHI) * common; + + *eval = make_float3(out, out, out); + } + } + } + } + else { + label = (m_refractive) ? LABEL_TRANSMIT | LABEL_GLOSSY : LABEL_REFLECT | LABEL_GLOSSY; + } + return label; } /* Beckmann microfacet with Smith shadow-masking from: @@ -764,364 +803,392 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure ccl_device int bsdf_microfacet_beckmann_setup(MicrofacetBsdf *bsdf) { - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ID; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_beckmann_aniso_setup(MicrofacetBsdf *bsdf) { - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = saturate(bsdf->alpha_y); + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = saturate(bsdf->alpha_y); - bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device int bsdf_microfacet_beckmann_refraction_setup(MicrofacetBsdf *bsdf) { - bsdf->alpha_x = saturate(bsdf->alpha_x); - bsdf->alpha_y = bsdf->alpha_x; + bsdf->alpha_x = saturate(bsdf->alpha_x); + bsdf->alpha_y = bsdf->alpha_x; - bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; - return SD_BSDF|SD_BSDF_HAS_EVAL; + bsdf->type = CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; + return SD_BSDF | SD_BSDF_HAS_EVAL; } ccl_device void bsdf_microfacet_beckmann_blur(ShaderClosure *sc, float roughness) { - MicrofacetBsdf *bsdf = (MicrofacetBsdf*)sc; + MicrofacetBsdf *bsdf = (MicrofacetBsdf *)sc; - bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x); - bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y); + bsdf->alpha_x = fmaxf(roughness, bsdf->alpha_x); + bsdf->alpha_y = fmaxf(roughness, bsdf->alpha_y); } ccl_device_inline float bsdf_beckmann_G1(float alpha, float cos_n) { - cos_n *= cos_n; - float invA = alpha * safe_sqrtf((1.0f - cos_n) / cos_n); - if(invA < 0.625f) { - return 1.0f; - } - - float a = 1.0f / invA; - return ((2.181f*a + 3.535f)*a) / ((2.577f*a + 2.276f)*a + 1.0f); + cos_n *= cos_n; + float invA = alpha * safe_sqrtf((1.0f - cos_n) / cos_n); + if (invA < 0.625f) { + return 1.0f; + } + + float a = 1.0f / invA; + return ((2.181f * a + 3.535f) * a) / ((2.577f * a + 2.276f) * a + 1.0f); } -ccl_device_inline float bsdf_beckmann_aniso_G1(float alpha_x, float alpha_y, float cos_n, float cos_phi, float sin_phi) +ccl_device_inline float bsdf_beckmann_aniso_G1( + float alpha_x, float alpha_y, float cos_n, float cos_phi, float sin_phi) { - cos_n *= cos_n; - sin_phi *= sin_phi; - cos_phi *= cos_phi; - alpha_x *= alpha_x; - alpha_y *= alpha_y; - - float alphaO2 = (cos_phi*alpha_x + sin_phi*alpha_y) / (cos_phi + sin_phi); - float invA = safe_sqrtf(alphaO2 * (1 - cos_n) / cos_n); - if(invA < 0.625f) { - return 1.0f; - } - - float a = 1.0f / invA; - return ((2.181f*a + 3.535f)*a) / ((2.577f*a + 2.276f)*a + 1.0f); + cos_n *= cos_n; + sin_phi *= sin_phi; + cos_phi *= cos_phi; + alpha_x *= alpha_x; + alpha_y *= alpha_y; + + float alphaO2 = (cos_phi * alpha_x + sin_phi * alpha_y) / (cos_phi + sin_phi); + float invA = safe_sqrtf(alphaO2 * (1 - cos_n) / cos_n); + if (invA < 0.625f) { + return 1.0f; + } + + float a = 1.0f / invA; + return ((2.181f * a + 3.535f) * a) / ((2.577f * a + 2.276f) * a + 1.0f); } -ccl_device float3 bsdf_microfacet_beckmann_eval_reflect(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +ccl_device float3 bsdf_microfacet_beckmann_eval_reflect(const ShaderClosure *sc, + const float3 I, + const float3 omega_in, + float *pdf) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; - float3 N = bsdf->N; - - if(m_refractive || alpha_x*alpha_y <= 1e-7f) - return make_float3(0.0f, 0.0f, 0.0f); - - float cosNO = dot(N, I); - float cosNI = dot(N, omega_in); - - if(cosNO > 0 && cosNI > 0) { - /* get half vector */ - float3 m = normalize(omega_in + I); - - float alpha2 = alpha_x * alpha_y; - float D, G1o, G1i; - - if(alpha_x == alpha_y) { - /* isotropic - * eq. 20: (F*G*D)/(4*in*on) - * eq. 25: first we calculate D(m) */ - float cosThetaM = dot(N, m); - float cosThetaM2 = cosThetaM * cosThetaM; - float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); - - /* eq. 26, 27: now calculate G1(i,m) and G1(o,m) */ - G1o = bsdf_beckmann_G1(alpha_x, cosNO); - G1i = bsdf_beckmann_G1(alpha_x, cosNI); - } - else { - /* anisotropic */ - float3 X, Y, Z = N; - make_orthonormals_tangent(Z, bsdf->T, &X, &Y); - - /* distribution */ - float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); - float slope_x = -local_m.x/(local_m.z*alpha_x); - float slope_y = -local_m.y/(local_m.z*alpha_y); - - float cosThetaM = local_m.z; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - - D = expf(-slope_x*slope_x - slope_y*slope_y) / (M_PI_F * alpha2 * cosThetaM4); - - /* G1(i,m) and G1(o,m) */ - G1o = bsdf_beckmann_aniso_G1(alpha_x, alpha_y, cosNO, dot(I, X), dot(I, Y)); - G1i = bsdf_beckmann_aniso_G1(alpha_x, alpha_y, cosNI, dot(omega_in, X), dot(omega_in, Y)); - } - - float G = G1o * G1i; - - /* eq. 20 */ - float common = D * 0.25f / cosNO; - float out = G * common; - - /* eq. 2 in distribution of visible normals sampling - * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ - - /* eq. 38 - but see also: - * eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf - * pdf = pm * 0.25 / dot(m, I); */ - *pdf = G1o * common; - - return make_float3(out, out, out); - } - - return make_float3(0.0f, 0.0f, 0.0f); + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; + float3 N = bsdf->N; + + if (m_refractive || alpha_x * alpha_y <= 1e-7f) + return make_float3(0.0f, 0.0f, 0.0f); + + float cosNO = dot(N, I); + float cosNI = dot(N, omega_in); + + if (cosNO > 0 && cosNI > 0) { + /* get half vector */ + float3 m = normalize(omega_in + I); + + float alpha2 = alpha_x * alpha_y; + float D, G1o, G1i; + + if (alpha_x == alpha_y) { + /* isotropic + * eq. 20: (F*G*D)/(4*in*on) + * eq. 25: first we calculate D(m) */ + float cosThetaM = dot(N, m); + float cosThetaM2 = cosThetaM * cosThetaM; + float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); + + /* eq. 26, 27: now calculate G1(i,m) and G1(o,m) */ + G1o = bsdf_beckmann_G1(alpha_x, cosNO); + G1i = bsdf_beckmann_G1(alpha_x, cosNI); + } + else { + /* anisotropic */ + float3 X, Y, Z = N; + make_orthonormals_tangent(Z, bsdf->T, &X, &Y); + + /* distribution */ + float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); + float slope_x = -local_m.x / (local_m.z * alpha_x); + float slope_y = -local_m.y / (local_m.z * alpha_y); + + float cosThetaM = local_m.z; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + + D = expf(-slope_x * slope_x - slope_y * slope_y) / (M_PI_F * alpha2 * cosThetaM4); + + /* G1(i,m) and G1(o,m) */ + G1o = bsdf_beckmann_aniso_G1(alpha_x, alpha_y, cosNO, dot(I, X), dot(I, Y)); + G1i = bsdf_beckmann_aniso_G1(alpha_x, alpha_y, cosNI, dot(omega_in, X), dot(omega_in, Y)); + } + + float G = G1o * G1i; + + /* eq. 20 */ + float common = D * 0.25f / cosNO; + float out = G * common; + + /* eq. 2 in distribution of visible normals sampling + * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ + + /* eq. 38 - but see also: + * eq. 17 in http://www.graphics.cornell.edu/~bjw/wardnotes.pdf + * pdf = pm * 0.25 / dot(m, I); */ + *pdf = G1o * common; + + return make_float3(out, out, out); + } + + return make_float3(0.0f, 0.0f, 0.0f); } -ccl_device float3 bsdf_microfacet_beckmann_eval_transmit(const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf) +ccl_device float3 bsdf_microfacet_beckmann_eval_transmit(const ShaderClosure *sc, + const float3 I, + const float3 omega_in, + float *pdf) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - float m_eta = bsdf->ior; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; - float3 N = bsdf->N; - - if(!m_refractive || alpha_x*alpha_y <= 1e-7f) - return make_float3(0.0f, 0.0f, 0.0f); - - float cosNO = dot(N, I); - float cosNI = dot(N, omega_in); - - if(cosNO <= 0 || cosNI >= 0) - return make_float3(0.0f, 0.0f, 0.0f); - - /* compute half-vector of the refraction (eq. 16) */ - float3 ht = -(m_eta * omega_in + I); - float3 Ht = normalize(ht); - float cosHO = dot(Ht, I); - float cosHI = dot(Ht, omega_in); - - /* eq. 25: first we calculate D(m) with m=Ht: */ - float alpha2 = alpha_x * alpha_y; - float cosThetaM = min(dot(N, Ht), 1.0f); - float cosThetaM2 = cosThetaM * cosThetaM; - float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); - - /* eq. 26, 27: now calculate G1(i,m) and G1(o,m) */ - float G1o = bsdf_beckmann_G1(alpha_x, cosNO); - float G1i = bsdf_beckmann_G1(alpha_x, cosNI); - float G = G1o * G1i; - - /* probability */ - float Ht2 = dot(ht, ht); - - /* eq. 2 in distribution of visible normals sampling - * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ - - /* out = fabsf(cosHI * cosHO) * (m_eta * m_eta) * G * D / (cosNO * Ht2) - * pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2 */ - float common = D * (m_eta * m_eta) / (cosNO * Ht2); - float out = G * fabsf(cosHI * cosHO) * common; - *pdf = G1o * fabsf(cosHO * cosHI) * common; - - return make_float3(out, out, out); + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + float m_eta = bsdf->ior; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; + float3 N = bsdf->N; + + if (!m_refractive || alpha_x * alpha_y <= 1e-7f) + return make_float3(0.0f, 0.0f, 0.0f); + + float cosNO = dot(N, I); + float cosNI = dot(N, omega_in); + + if (cosNO <= 0 || cosNI >= 0) + return make_float3(0.0f, 0.0f, 0.0f); + + /* compute half-vector of the refraction (eq. 16) */ + float3 ht = -(m_eta * omega_in + I); + float3 Ht = normalize(ht); + float cosHO = dot(Ht, I); + float cosHI = dot(Ht, omega_in); + + /* eq. 25: first we calculate D(m) with m=Ht: */ + float alpha2 = alpha_x * alpha_y; + float cosThetaM = min(dot(N, Ht), 1.0f); + float cosThetaM2 = cosThetaM * cosThetaM; + float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); + + /* eq. 26, 27: now calculate G1(i,m) and G1(o,m) */ + float G1o = bsdf_beckmann_G1(alpha_x, cosNO); + float G1i = bsdf_beckmann_G1(alpha_x, cosNI); + float G = G1o * G1i; + + /* probability */ + float Ht2 = dot(ht, ht); + + /* eq. 2 in distribution of visible normals sampling + * pm = Dw = G1o * dot(m, I) * D / dot(N, I); */ + + /* out = fabsf(cosHI * cosHO) * (m_eta * m_eta) * G * D / (cosNO * Ht2) + * pdf = pm * (m_eta * m_eta) * fabsf(cosHI) / Ht2 */ + float common = D * (m_eta * m_eta) / (cosNO * Ht2); + float out = G * fabsf(cosHI * cosHO) * common; + *pdf = G1o * fabsf(cosHO * cosHI) * common; + + return make_float3(out, out, out); } -ccl_device int bsdf_microfacet_beckmann_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) +ccl_device int bsdf_microfacet_beckmann_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) { - const MicrofacetBsdf *bsdf = (const MicrofacetBsdf*)sc; - float alpha_x = bsdf->alpha_x; - float alpha_y = bsdf->alpha_y; - bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; - float3 N = bsdf->N; - int label; - - float cosNO = dot(N, I); - if(cosNO > 0) { - float3 X, Y, Z = N; - - if(alpha_x == alpha_y) - make_orthonormals(Z, &X, &Y); - else - make_orthonormals_tangent(Z, bsdf->T, &X, &Y); - - /* importance sampling with distribution of visible normals. vectors are - * transformed to local space before and after */ - float3 local_I = make_float3(dot(X, I), dot(Y, I), cosNO); - float3 local_m; - float G1o; - - local_m = microfacet_sample_stretched(kg, local_I, alpha_x, alpha_x, - randu, randv, true, &G1o); - - float3 m = X*local_m.x + Y*local_m.y + Z*local_m.z; - float cosThetaM = local_m.z; - - /* reflection or refraction? */ - if(!m_refractive) { - label = LABEL_REFLECT | LABEL_GLOSSY; - float cosMO = dot(m, I); - - if(cosMO > 0) { - /* eq. 39 - compute actual reflected direction */ - *omega_in = 2 * cosMO * m - I; - - if(dot(Ng, *omega_in) > 0) { - if(alpha_x*alpha_y <= 1e-7f) { - /* some high number for MIS */ - *pdf = 1e6f; - *eval = make_float3(1e6f, 1e6f, 1e6f); - label = LABEL_REFLECT | LABEL_SINGULAR; - } - else { - /* microfacet normal is visible to this ray - * eq. 25 */ - float alpha2 = alpha_x * alpha_y; - float D, G1i; - - if(alpha_x == alpha_y) { - /* istropic distribution */ - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float tanThetaM2 = 1/(cosThetaM2) - 1; - D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); - - /* eval BRDF*cosNI */ - float cosNI = dot(N, *omega_in); - - /* eq. 26, 27: now calculate G1(i,m) */ - G1i = bsdf_beckmann_G1(alpha_x, cosNI); - } - else { - /* anisotropic distribution */ - float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); - float slope_x = -local_m.x/(local_m.z*alpha_x); - float slope_y = -local_m.y/(local_m.z*alpha_y); - - float cosThetaM = local_m.z; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - - D = expf(-slope_x*slope_x - slope_y*slope_y) / (M_PI_F * alpha2 * cosThetaM4); - - /* G1(i,m) */ - G1i = bsdf_beckmann_aniso_G1(alpha_x, alpha_y, dot(*omega_in, N), dot(*omega_in, X), dot(*omega_in, Y)); - } - - float G = G1o * G1i; - - /* see eval function for derivation */ - float common = D * 0.25f / cosNO; - float out = G * common; - *pdf = G1o * common; - - *eval = make_float3(out, out, out); - } + const MicrofacetBsdf *bsdf = (const MicrofacetBsdf *)sc; + float alpha_x = bsdf->alpha_x; + float alpha_y = bsdf->alpha_y; + bool m_refractive = bsdf->type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID; + float3 N = bsdf->N; + int label; + + float cosNO = dot(N, I); + if (cosNO > 0) { + float3 X, Y, Z = N; + + if (alpha_x == alpha_y) + make_orthonormals(Z, &X, &Y); + else + make_orthonormals_tangent(Z, bsdf->T, &X, &Y); + + /* importance sampling with distribution of visible normals. vectors are + * transformed to local space before and after */ + float3 local_I = make_float3(dot(X, I), dot(Y, I), cosNO); + float3 local_m; + float G1o; + + local_m = microfacet_sample_stretched(kg, local_I, alpha_x, alpha_x, randu, randv, true, &G1o); + + float3 m = X * local_m.x + Y * local_m.y + Z * local_m.z; + float cosThetaM = local_m.z; + + /* reflection or refraction? */ + if (!m_refractive) { + label = LABEL_REFLECT | LABEL_GLOSSY; + float cosMO = dot(m, I); + + if (cosMO > 0) { + /* eq. 39 - compute actual reflected direction */ + *omega_in = 2 * cosMO * m - I; + + if (dot(Ng, *omega_in) > 0) { + if (alpha_x * alpha_y <= 1e-7f) { + /* some high number for MIS */ + *pdf = 1e6f; + *eval = make_float3(1e6f, 1e6f, 1e6f); + label = LABEL_REFLECT | LABEL_SINGULAR; + } + else { + /* microfacet normal is visible to this ray + * eq. 25 */ + float alpha2 = alpha_x * alpha_y; + float D, G1i; + + if (alpha_x == alpha_y) { + /* istropic distribution */ + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float tanThetaM2 = 1 / (cosThetaM2)-1; + D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); + + /* eval BRDF*cosNI */ + float cosNI = dot(N, *omega_in); + + /* eq. 26, 27: now calculate G1(i,m) */ + G1i = bsdf_beckmann_G1(alpha_x, cosNI); + } + else { + /* anisotropic distribution */ + float3 local_m = make_float3(dot(X, m), dot(Y, m), dot(Z, m)); + float slope_x = -local_m.x / (local_m.z * alpha_x); + float slope_y = -local_m.y / (local_m.z * alpha_y); + + float cosThetaM = local_m.z; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + + D = expf(-slope_x * slope_x - slope_y * slope_y) / (M_PI_F * alpha2 * cosThetaM4); + + /* G1(i,m) */ + G1i = bsdf_beckmann_aniso_G1( + alpha_x, alpha_y, dot(*omega_in, N), dot(*omega_in, X), dot(*omega_in, Y)); + } + + float G = G1o * G1i; + + /* see eval function for derivation */ + float common = D * 0.25f / cosNO; + float out = G * common; + *pdf = G1o * common; + + *eval = make_float3(out, out, out); + } #ifdef __RAY_DIFFERENTIALS__ - *domega_in_dx = (2 * dot(m, dIdx)) * m - dIdx; - *domega_in_dy = (2 * dot(m, dIdy)) * m - dIdy; + *domega_in_dx = (2 * dot(m, dIdx)) * m - dIdx; + *domega_in_dy = (2 * dot(m, dIdy)) * m - dIdy; #endif - } - } - } - else { - label = LABEL_TRANSMIT | LABEL_GLOSSY; - - /* CAUTION: the i and o variables are inverted relative to the paper - * eq. 39 - compute actual refractive direction */ - float3 R, T; + } + } + } + else { + label = LABEL_TRANSMIT | LABEL_GLOSSY; + + /* CAUTION: the i and o variables are inverted relative to the paper + * eq. 39 - compute actual refractive direction */ + float3 R, T; #ifdef __RAY_DIFFERENTIALS__ - float3 dRdx, dRdy, dTdx, dTdy; + float3 dRdx, dRdy, dTdx, dTdy; #endif - float m_eta = bsdf->ior, fresnel; - bool inside; - - fresnel = fresnel_dielectric(m_eta, m, I, &R, &T, + float m_eta = bsdf->ior, fresnel; + bool inside; + + fresnel = fresnel_dielectric(m_eta, + m, + I, + &R, + &T, #ifdef __RAY_DIFFERENTIALS__ - dIdx, dIdy, &dRdx, &dRdy, &dTdx, &dTdy, + dIdx, + dIdy, + &dRdx, + &dRdy, + &dTdx, + &dTdy, #endif - &inside); + &inside); - if(!inside && fresnel != 1.0f) { - *omega_in = T; + if (!inside && fresnel != 1.0f) { + *omega_in = T; #ifdef __RAY_DIFFERENTIALS__ - *domega_in_dx = dTdx; - *domega_in_dy = dTdy; + *domega_in_dx = dTdx; + *domega_in_dy = dTdy; #endif - if(alpha_x*alpha_y <= 1e-7f || fabsf(m_eta - 1.0f) < 1e-4f) { - /* some high number for MIS */ - *pdf = 1e6f; - *eval = make_float3(1e6f, 1e6f, 1e6f); - label = LABEL_TRANSMIT | LABEL_SINGULAR; - } - else { - /* eq. 33 */ - float alpha2 = alpha_x * alpha_y; - float cosThetaM2 = cosThetaM * cosThetaM; - float cosThetaM4 = cosThetaM2 * cosThetaM2; - float tanThetaM2 = 1/(cosThetaM2) - 1; - float D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); - - /* eval BRDF*cosNI */ - float cosNI = dot(N, *omega_in); - - /* eq. 26, 27: now calculate G1(i,m) */ - float G1i = bsdf_beckmann_G1(alpha_x, cosNI); - float G = G1o * G1i; - - /* eq. 21 */ - float cosHI = dot(m, *omega_in); - float cosHO = dot(m, I); - float Ht2 = m_eta * cosHI + cosHO; - Ht2 *= Ht2; - - /* see eval function for derivation */ - float common = D * (m_eta * m_eta) / (cosNO * Ht2); - float out = G * fabsf(cosHI * cosHO) * common; - *pdf = G1o * cosHO * fabsf(cosHI) * common; - - *eval = make_float3(out, out, out); - } - } - } - } - else { - label = (m_refractive) ? LABEL_TRANSMIT|LABEL_GLOSSY : LABEL_REFLECT|LABEL_GLOSSY; - } - return label; + if (alpha_x * alpha_y <= 1e-7f || fabsf(m_eta - 1.0f) < 1e-4f) { + /* some high number for MIS */ + *pdf = 1e6f; + *eval = make_float3(1e6f, 1e6f, 1e6f); + label = LABEL_TRANSMIT | LABEL_SINGULAR; + } + else { + /* eq. 33 */ + float alpha2 = alpha_x * alpha_y; + float cosThetaM2 = cosThetaM * cosThetaM; + float cosThetaM4 = cosThetaM2 * cosThetaM2; + float tanThetaM2 = 1 / (cosThetaM2)-1; + float D = expf(-tanThetaM2 / alpha2) / (M_PI_F * alpha2 * cosThetaM4); + + /* eval BRDF*cosNI */ + float cosNI = dot(N, *omega_in); + + /* eq. 26, 27: now calculate G1(i,m) */ + float G1i = bsdf_beckmann_G1(alpha_x, cosNI); + float G = G1o * G1i; + + /* eq. 21 */ + float cosHI = dot(m, *omega_in); + float cosHO = dot(m, I); + float Ht2 = m_eta * cosHI + cosHO; + Ht2 *= Ht2; + + /* see eval function for derivation */ + float common = D * (m_eta * m_eta) / (cosNO * Ht2); + float out = G * fabsf(cosHI * cosHO) * common; + *pdf = G1o * cosHO * fabsf(cosHI) * common; + + *eval = make_float3(out, out, out); + } + } + } + } + else { + label = (m_refractive) ? LABEL_TRANSMIT | LABEL_GLOSSY : LABEL_REFLECT | LABEL_GLOSSY; + } + return label; } CCL_NAMESPACE_END -#endif /* __BSDF_MICROFACET_H__ */ +#endif /* __BSDF_MICROFACET_H__ */ |