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Diffstat (limited to 'intern/cycles/kernel/closure/bsdf_principled_diffuse.h')
-rw-r--r-- | intern/cycles/kernel/closure/bsdf_principled_diffuse.h | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/intern/cycles/kernel/closure/bsdf_principled_diffuse.h b/intern/cycles/kernel/closure/bsdf_principled_diffuse.h new file mode 100644 index 00000000000..f8ca64293b0 --- /dev/null +++ b/intern/cycles/kernel/closure/bsdf_principled_diffuse.h @@ -0,0 +1,127 @@ +/* + * Copyright 2011-2017 Blender Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef __BSDF_PRINCIPLED_DIFFUSE_H__ +#define __BSDF_PRINCIPLED_DIFFUSE_H__ + +/* DISNEY PRINCIPLED DIFFUSE BRDF + * + * Shading model by Brent Burley (Disney): "Physically Based Shading at Disney" (2012) + */ + +CCL_NAMESPACE_BEGIN + +typedef ccl_addr_space struct PrincipledDiffuseBsdf { + SHADER_CLOSURE_BASE; + + float roughness; +} PrincipledDiffuseBsdf; + +ccl_device float3 calculate_principled_diffuse_brdf(const PrincipledDiffuseBsdf *bsdf, + float3 N, float3 V, float3 L, float3 H, float *pdf) +{ + float NdotL = max(dot(N, L), 0.0f); + float NdotV = max(dot(N, V), 0.0f); + + if(NdotL < 0 || NdotV < 0) { + *pdf = 0.0f; + return make_float3(0.0f, 0.0f, 0.0f); + } + + float LdotH = dot(L, H); + + float FL = schlick_fresnel(NdotL), FV = schlick_fresnel(NdotV); + const float Fd90 = 0.5f + 2.0f * LdotH*LdotH * bsdf->roughness; + float Fd = (1.0f * (1.0f - FL) + Fd90 * FL) * (1.0f * (1.0f - FV) + Fd90 * FV); + + float value = M_1_PI_F * NdotL * Fd; + + return make_float3(value, value, value); +} + +ccl_device int bsdf_principled_diffuse_setup(PrincipledDiffuseBsdf *bsdf) +{ + bsdf->type = CLOSURE_BSDF_PRINCIPLED_DIFFUSE_ID; + return SD_BSDF|SD_BSDF_HAS_EVAL; +} + +ccl_device bool bsdf_principled_diffuse_merge(const ShaderClosure *a, const ShaderClosure *b) +{ + const PrincipledDiffuseBsdf *bsdf_a = (const PrincipledDiffuseBsdf*)a; + const PrincipledDiffuseBsdf *bsdf_b = (const PrincipledDiffuseBsdf*)b; + + return (isequal_float3(bsdf_a->N, bsdf_b->N) && bsdf_a->roughness == bsdf_b->roughness); +} + +ccl_device float3 bsdf_principled_diffuse_eval_reflect(const ShaderClosure *sc, const float3 I, + const float3 omega_in, float *pdf) +{ + const PrincipledDiffuseBsdf *bsdf = (const PrincipledDiffuseBsdf *)sc; + + float3 N = bsdf->N; + float3 V = I; // outgoing + float3 L = omega_in; // incoming + float3 H = normalize(L + V); + + if(dot(N, omega_in) > 0.0f) { + *pdf = fmaxf(dot(N, omega_in), 0.0f) * M_1_PI_F; + return calculate_principled_diffuse_brdf(bsdf, N, V, L, H, pdf); + } + else { + *pdf = 0.0f; + return make_float3(0.0f, 0.0f, 0.0f); + } +} + +ccl_device float3 bsdf_principled_diffuse_eval_transmit(const ShaderClosure *sc, const float3 I, + const float3 omega_in, float *pdf) +{ + return make_float3(0.0f, 0.0f, 0.0f); +} + +ccl_device int bsdf_principled_diffuse_sample(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 PrincipledDiffuseBsdf *bsdf = (const PrincipledDiffuseBsdf *)sc; + + float3 N = bsdf->N; + + sample_cos_hemisphere(N, randu, randv, omega_in, pdf); + + if(dot(Ng, *omega_in) > 0) { + float3 H = normalize(I + *omega_in); + + *eval = calculate_principled_diffuse_brdf(bsdf, N, I, *omega_in, H, pdf); + +#ifdef __RAY_DIFFERENTIALS__ + // TODO: find a better approximation for the diffuse bounce + *domega_in_dx = -((2 * dot(N, dIdx)) * N - dIdx); + *domega_in_dy = -((2 * dot(N, dIdy)) * N - dIdy); +#endif + } + else { + *pdf = 0.0f; + } + return LABEL_REFLECT|LABEL_DIFFUSE; +} + +CCL_NAMESPACE_END + +#endif /* __BSDF_PRINCIPLED_DIFFUSE_H__ */ + + |