/*
 * Copyright 2011-2013 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.
 */

CCL_NAMESPACE_BEGIN

/* Closure Nodes */

ccl_device void svm_node_glass_setup(ShaderData *sd, MicrofacetBsdf *bsdf, int type, float eta, float roughness, bool refract)
{
	if(type == CLOSURE_BSDF_SHARP_GLASS_ID) {
		if(refract) {
			bsdf->alpha_y = 0.0f;
			bsdf->alpha_x = 0.0f;
			bsdf->ior = eta;
			sd->flag |= bsdf_refraction_setup(bsdf);
		}
		else {
			bsdf->alpha_y = 0.0f;
			bsdf->alpha_x = 0.0f;
			bsdf->ior = 0.0f;
			sd->flag |= bsdf_reflection_setup(bsdf);
		}
	}
	else if(type == CLOSURE_BSDF_MICROFACET_BECKMANN_GLASS_ID) {
		bsdf->alpha_x = roughness;
		bsdf->alpha_y = roughness;
		bsdf->ior = eta;

		if(refract)
			sd->flag |= bsdf_microfacet_beckmann_refraction_setup(bsdf);
		else
			sd->flag |= bsdf_microfacet_beckmann_setup(bsdf);
	}
	else {
		bsdf->alpha_x = roughness;
		bsdf->alpha_y = roughness;
		bsdf->ior = eta;

		if(refract)
			sd->flag |= bsdf_microfacet_ggx_refraction_setup(bsdf);
		else
			sd->flag |= bsdf_microfacet_ggx_setup(bsdf);
	}
}

ccl_device void svm_node_closure_bsdf(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int path_flag, int *offset)
{
	uint type, param1_offset, param2_offset;

	uint mix_weight_offset;
	decode_node_uchar4(node.y, &type, &param1_offset, &param2_offset, &mix_weight_offset);
	float mix_weight = (stack_valid(mix_weight_offset)? stack_load_float(stack, mix_weight_offset): 1.0f);

	/* note we read this extra node before weight check, so offset is added */
	uint4 data_node = read_node(kg, offset);

	if(mix_weight == 0.0f)
		return;

	float3 N = stack_valid(data_node.x)? stack_load_float3(stack, data_node.x): sd->N;

	float param1 = (stack_valid(param1_offset))? stack_load_float(stack, param1_offset): __uint_as_float(node.z);
	float param2 = (stack_valid(param2_offset))? stack_load_float(stack, param2_offset): __uint_as_float(node.w);

	switch(type) {
		case CLOSURE_BSDF_PRINCIPLED_ID: {
			uint specular_offset, roughness_offset, specular_tint_offset, anisotropic_offset, sheen_offset,
				sheen_tint_offset, clearcoat_offset, clearcoat_gloss_offset, eta_offset, transparency_offset,
				anisotropic_rotation_offset, refraction_roughness_offset;
			uint4 data_node2 = read_node(kg, offset);

			float3 T = stack_load_float3(stack, data_node.y);
			decode_node_uchar4(data_node.z, &specular_offset, &roughness_offset, &specular_tint_offset, &anisotropic_offset);
			decode_node_uchar4(data_node.w, &sheen_offset, &sheen_tint_offset, &clearcoat_offset, &clearcoat_gloss_offset);
			decode_node_uchar4(data_node2.x, &eta_offset, &transparency_offset, &anisotropic_rotation_offset, &refraction_roughness_offset);

			// get Disney principled parameters
			float metallic = param1;
			float subsurface = param2;
			float specular = stack_load_float(stack, specular_offset);
			float roughness = stack_load_float(stack, roughness_offset);
			float specular_tint = stack_load_float(stack, specular_tint_offset);
			float anisotropic = stack_load_float(stack, anisotropic_offset);
			float sheen = stack_load_float(stack, sheen_offset);
			float sheen_tint = stack_load_float(stack, sheen_tint_offset);
			float clearcoat = stack_load_float(stack, clearcoat_offset);
			float clearcoat_gloss = stack_load_float(stack, clearcoat_gloss_offset);
			float transparency = stack_load_float(stack, transparency_offset);
			float anisotropic_rotation = stack_load_float(stack, anisotropic_rotation_offset);
			float refraction_roughness = stack_load_float(stack, refraction_roughness_offset);
			float eta = fmaxf(stack_load_float(stack, eta_offset), 1e-5f);

			ClosureType distribution = stack_valid(data_node2.y) ? (ClosureType) data_node2.y : CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID;

			/* rotate tangent */
			if(anisotropic_rotation != 0.0f)
				T = rotate_around_axis(T, N, anisotropic_rotation * M_2PI_F);

			/* calculate ior */
			float ior = (sd->flag & SD_BACKFACING) ? 1.0f / eta : eta;

			// calculate fresnel for refraction
			float cosNO = dot(N, sd->I);
			float fresnel = fresnel_dielectric_cos(cosNO, ior);

			// calculate weights of the diffuse and specular part
			float diffuse_weight = (1.0f - saturate(metallic)) * (1.0f - saturate(transparency));
			
			float transp = saturate(transparency) * (1.0f - saturate(metallic));
			float specular_weight = (1.0f - transp);

			// get the base color
			uint4 data_base_color = read_node(kg, offset);
			float3 base_color = stack_valid(data_base_color.x) ? stack_load_float3(stack, data_base_color.x) :
				make_float3(__uint_as_float(data_base_color.y), __uint_as_float(data_base_color.z), __uint_as_float(data_base_color.w));

			// get the additional clearcoat normal and subsurface scattering radius
			uint4 data_cn_ssr = read_node(kg, offset);
			float3 clearcoat_normal = stack_valid(data_cn_ssr.x) ? stack_load_float3(stack, data_cn_ssr.x) : sd->N;
			float3 subsurface_radius = stack_valid(data_cn_ssr.y) ? stack_load_float3(stack, data_cn_ssr.y) : make_float3(1.0f, 1.0f, 1.0f);

			// get the subsurface color
			uint4 data_subsurface_color = read_node(kg, offset);
			float3 subsurface_color = stack_valid(data_subsurface_color.x) ? stack_load_float3(stack, data_subsurface_color.x) :
				make_float3(__uint_as_float(data_subsurface_color.y), __uint_as_float(data_subsurface_color.z), __uint_as_float(data_subsurface_color.w));

			float3 weight = sd->svm_closure_weight * mix_weight;

#ifdef __SUBSURFACE__
			float3 albedo = subsurface_color * subsurface + base_color * (1.0f - subsurface);
			float3 subsurf_weight = weight * albedo * diffuse_weight;
			float subsurf_sample_weight = fabsf(average(subsurf_weight));

			/* disable in case of diffuse ancestor, can't see it well then and
			 * adds considerably noise due to probabilities of continuing path
			 * getting lower and lower */
			if(path_flag & PATH_RAY_DIFFUSE_ANCESTOR) {
				subsurface = 0.0f;
			}

			/* diffuse */
			if(fabsf(average(base_color)) > CLOSURE_WEIGHT_CUTOFF) {
				if(subsurface < CLOSURE_WEIGHT_CUTOFF && diffuse_weight > CLOSURE_WEIGHT_CUTOFF) {
					float3 diff_weight = weight * base_color * diffuse_weight;

					PrincipledDiffuseBsdf *bsdf = (PrincipledDiffuseBsdf*)bsdf_alloc(sd, sizeof(PrincipledDiffuseBsdf), diff_weight);

					if(bsdf) {
						bsdf->N = N;
						bsdf->roughness = roughness;

						/* setup bsdf */
						sd->flag |= bsdf_principled_diffuse_setup(bsdf);
					}
				}
				else if(subsurface > CLOSURE_WEIGHT_CUTOFF && subsurf_sample_weight > CLOSURE_WEIGHT_CUTOFF) {
					/* radius * scale */
					float3 radius = subsurface_radius * subsurface;
					/* sharpness */
					float sharpness = 0.0f;
					/* texture color blur */
					float texture_blur = 0.0f;

					/* create one closure per color channel */
					Bssrdf *bssrdf = bssrdf_alloc(sd, make_float3(subsurf_weight.x, 0.0f, 0.0f));
					if(bssrdf) {
						bssrdf->sample_weight = subsurf_sample_weight;
						bssrdf->radius = radius.x;
						bssrdf->texture_blur = texture_blur;
						bssrdf->albedo = albedo.x;
						bssrdf->sharpness = sharpness;
						bssrdf->N = N;
						bssrdf->roughness = roughness;

						/* setup bsdf */
						sd->flag |= bssrdf_setup(bssrdf, (ClosureType)CLOSURE_BSSRDF_PRINCIPLED_ID);
					}

					bssrdf = bssrdf_alloc(sd, make_float3(0.0f, subsurf_weight.y, 0.0f));
					if(bssrdf) {
						bssrdf->sample_weight = subsurf_sample_weight;
						bssrdf->radius = radius.y;
						bssrdf->texture_blur = texture_blur;
						bssrdf->albedo = albedo.y;
						bssrdf->sharpness = sharpness;
						bssrdf->N = N;
						bssrdf->roughness = roughness;

						/* setup bsdf */
						sd->flag |= bssrdf_setup(bssrdf, (ClosureType)CLOSURE_BSSRDF_PRINCIPLED_ID);
					}

					bssrdf = bssrdf_alloc(sd, make_float3(0.0f, 0.0f, subsurf_weight.z));
					if(bssrdf) {
						bssrdf->sample_weight = subsurf_sample_weight;
						bssrdf->radius = radius.z;
						bssrdf->texture_blur = texture_blur;
						bssrdf->albedo = albedo.z;
						bssrdf->sharpness = sharpness;
						bssrdf->N = N;
						bssrdf->roughness = roughness;

						/* setup bsdf */
						sd->flag |= bssrdf_setup(bssrdf, (ClosureType)CLOSURE_BSSRDF_PRINCIPLED_ID);
					}
				}
			}
#else
			/* diffuse */
			if(diffuse_weight > CLOSURE_WEIGHT_CUTOFF) {
				float3 diff_weight = weight * base_color * diffuse_weight;

				PrincipledDiffuseBsdf *bsdf = (PrincipledDiffuseBsdf*)bsdf_alloc(sd, sizeof(PrincipledDiffuseBsdf), diff_weight);

				if(bsdf) {
					bsdf->N = N;
					bsdf->roughness = roughness;

					/* setup bsdf */
					sd->flag |= bsdf_principled_diffuse_setup(bsdf);
				}
			}
#endif

			/* sheen */
			if(diffuse_weight > CLOSURE_WEIGHT_CUTOFF && sheen > CLOSURE_WEIGHT_CUTOFF) {
				float m_cdlum = linear_rgb_to_gray(base_color);
				float3 m_ctint = m_cdlum > 0.0f ? base_color / m_cdlum : make_float3(1.0f, 1.0f, 1.0f); // normalize lum. to isolate hue+sat

				/* color of the sheen component */
				float3 sheen_color = make_float3(1.0f, 1.0f, 1.0f) * (1.0f - sheen_tint) + m_ctint * sheen_tint;

				float3 sheen_weight = weight * sheen * sheen_color * diffuse_weight;

				PrincipledSheenBsdf *bsdf = (PrincipledSheenBsdf*)bsdf_alloc(sd, sizeof(PrincipledSheenBsdf), sheen_weight);

				if(bsdf) {
					bsdf->N = N;

					/* setup bsdf */
					sd->flag |= bsdf_principled_sheen_setup(bsdf);
				}
			}

			/* specular reflection */
#ifdef __CAUSTICS_TRICKS__
			if(kernel_data.integrator.caustics_reflective || (path_flag & PATH_RAY_DIFFUSE) == 0) {
#endif
				if(specular_weight > CLOSURE_WEIGHT_CUTOFF && (specular > CLOSURE_WEIGHT_CUTOFF || metallic > CLOSURE_WEIGHT_CUTOFF)) {
					float3 spec_weight = weight * specular_weight;

					MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), spec_weight);
					MicrofacetExtra *extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));

					if(bsdf && extra) {
						bsdf->N = N;
						bsdf->ior = (2.0f / (1.0f - safe_sqrtf(0.08f * specular))) - 1.0f;
						bsdf->T = T;
						bsdf->extra = extra;

						float aspect = safe_sqrtf(1.0f - anisotropic * 0.9f);
						float r2 = roughness * roughness;

						bsdf->alpha_x = fmaxf(0.001f, r2 / aspect);
						bsdf->alpha_y = fmaxf(0.001f, r2 * aspect);

						float m_cdlum = 0.3f * base_color.x + 0.6f * base_color.y + 0.1f * base_color.z; // luminance approx.
						float3 m_ctint = m_cdlum > 0.0f ? base_color / m_cdlum : make_float3(0.0f, 0.0f, 0.0f); // normalize lum. to isolate hue+sat
						float3 tmp_col = make_float3(1.0f, 1.0f, 1.0f) * (1.0f - specular_tint) + m_ctint * specular_tint;

						bsdf->extra->cspec0 = (specular * 0.08f * tmp_col) * (1.0f - metallic) + base_color * metallic;
						bsdf->extra->color = base_color;

						/* setup bsdf */
						if(distribution == CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID || roughness <= 0.075f) /* use single-scatter GGX */
							sd->flag |= bsdf_microfacet_ggx_aniso_fresnel_setup(bsdf);
						else /* use multi-scatter GGX */
							sd->flag |= bsdf_microfacet_multi_ggx_aniso_fresnel_setup(bsdf);
					}
				}
#ifdef __CAUSTICS_TRICKS__
			}
#endif

			/* BSDF */
#ifdef __CAUSTICS_TRICKS__
			if(kernel_data.integrator.caustics_reflective || kernel_data.integrator.caustics_refractive || (path_flag & PATH_RAY_DIFFUSE) == 0) {
#endif
				if(transp > CLOSURE_WEIGHT_CUTOFF) {
					float3 glass_weight = weight * transp;
					float3 cspec0 = base_color * specular_tint + make_float3(1.0f, 1.0f, 1.0f) * (1.0f - specular_tint);

					if(roughness <= 5e-2f || distribution == CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID) { /* use single-scatter GGX */
						float refl_roughness = roughness;

						/* reflection */
#ifdef __CAUSTICS_TRICKS__
						if(kernel_data.integrator.caustics_reflective || (path_flag & PATH_RAY_DIFFUSE) == 0)
#endif
						{
							MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), glass_weight*fresnel);
							MicrofacetExtra *extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));

							if(bsdf && extra) {
								bsdf->N = N;
								bsdf->extra = extra;

								bsdf->alpha_x = refl_roughness * refl_roughness;
								bsdf->alpha_y = refl_roughness * refl_roughness;
								bsdf->ior = ior;

								bsdf->extra->color = base_color;
								bsdf->extra->cspec0 = cspec0;

								/* setup bsdf */
								sd->flag |= bsdf_microfacet_ggx_fresnel_setup(bsdf);
							}
						}

						/* refraction */
#ifdef __CAUSTICS_TRICKS__
						if(kernel_data.integrator.caustics_refractive || (path_flag & PATH_RAY_DIFFUSE) == 0)
#endif
						{
							MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), base_color*glass_weight*(1.0f - fresnel));

							if(bsdf) {
								bsdf->N = N;

								if(distribution == CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID)
									refraction_roughness = 1.0f - (1.0f - refl_roughness) * (1.0f - refraction_roughness);
								else
									refraction_roughness = refl_roughness;

								bsdf->alpha_x = refraction_roughness * refraction_roughness;
								bsdf->alpha_y = refraction_roughness * refraction_roughness;
								bsdf->ior = ior;

								/* setup bsdf */
								sd->flag |= bsdf_microfacet_ggx_refraction_setup(bsdf);
							}
						}
					}
					else { /* use multi-scatter GGX */
						MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), glass_weight);
						MicrofacetExtra *extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));

						if(bsdf && extra) {
							bsdf->N = N;
							bsdf->extra = extra;
							bsdf->T = make_float3(0.0f, 0.0f, 0.0f);

							bsdf->alpha_x = roughness * roughness;
							bsdf->alpha_y = roughness * roughness;
							bsdf->ior = ior;

							bsdf->extra->color = base_color;
							bsdf->extra->cspec0 = cspec0;

							/* setup bsdf */
							sd->flag |= bsdf_microfacet_multi_ggx_glass_fresnel_setup(bsdf);
						}
					}
				}
#ifdef __CAUSTICS_TRICKS__
			}
#endif

			/* clearcoat */
#ifdef __CAUSTICS_TRICKS__
			if(kernel_data.integrator.caustics_reflective || (path_flag & PATH_RAY_DIFFUSE) == 0) {
#endif
				if(clearcoat > CLOSURE_WEIGHT_CUTOFF) {
					MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight);
					MicrofacetExtra *extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));

					if(bsdf && extra) {
						bsdf->N = clearcoat_normal;
						bsdf->ior = 1.5f;
						bsdf->extra = extra;

						bsdf->alpha_x = 0.1f * (1.0f - clearcoat_gloss) + 0.001f * clearcoat_gloss;
						bsdf->alpha_y = 0.1f * (1.0f - clearcoat_gloss) + 0.001f * clearcoat_gloss;

						bsdf->extra->cspec0 = make_float3(0.04f, 0.04f, 0.04f);
						bsdf->extra->clearcoat = clearcoat;

						/* setup bsdf */
						sd->flag |= bsdf_microfacet_ggx_clearcoat_setup(bsdf);
					}
				}
#ifdef __CAUSTICS_TRICKS__
			}
#endif

			break;
		}
		case CLOSURE_BSDF_DIFFUSE_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			OrenNayarBsdf *bsdf = (OrenNayarBsdf*)bsdf_alloc(sd, sizeof(OrenNayarBsdf), weight);

			if(bsdf) {
				bsdf->N = N;

				float roughness = param1;

				if(roughness == 0.0f) {
					sd->flag |= bsdf_diffuse_setup((DiffuseBsdf*)bsdf);
				}
				else {
					bsdf->roughness = roughness;
					sd->flag |= bsdf_oren_nayar_setup(bsdf);
				}
			}
			break;
		}
		case CLOSURE_BSDF_TRANSLUCENT_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			DiffuseBsdf *bsdf = (DiffuseBsdf*)bsdf_alloc(sd, sizeof(DiffuseBsdf), weight);

			if(bsdf) {
				bsdf->N = N;
				sd->flag |= bsdf_translucent_setup(bsdf);
			}
			break;
		}
		case CLOSURE_BSDF_TRANSPARENT_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			ShaderClosure *bsdf = bsdf_alloc(sd, sizeof(ShaderClosure), weight);

			if(bsdf) {
				sd->flag |= bsdf_transparent_setup(bsdf);
			}
			break;
		}
		case CLOSURE_BSDF_REFLECTION_ID:
		case CLOSURE_BSDF_MICROFACET_GGX_ID:
		case CLOSURE_BSDF_MICROFACET_BECKMANN_ID:
		case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ID:
		case CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID: {
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_reflective && (path_flag & PATH_RAY_DIFFUSE))
				break;
#endif
			float3 weight = sd->svm_closure_weight * mix_weight;
			MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight);

			if(bsdf) {
				bsdf->N = N;
				bsdf->alpha_x = param1;
				bsdf->alpha_y = param1;
				bsdf->ior = 0.0f;
				bsdf->extra = NULL;

				/* setup bsdf */
				if(type == CLOSURE_BSDF_REFLECTION_ID)
					sd->flag |= bsdf_reflection_setup(bsdf);
				else if(type == CLOSURE_BSDF_MICROFACET_BECKMANN_ID)
					sd->flag |= bsdf_microfacet_beckmann_setup(bsdf);
				else if(type == CLOSURE_BSDF_MICROFACET_GGX_ID)
					sd->flag |= bsdf_microfacet_ggx_setup(bsdf);
				else if(type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_ID) {
					kernel_assert(stack_valid(data_node.z));
					bsdf->extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));
					if(bsdf->extra) {
						bsdf->extra->color = stack_load_float3(stack, data_node.z);
						sd->flag |= bsdf_microfacet_multi_ggx_setup(bsdf);
					}
				}
				else
					sd->flag |= bsdf_ashikhmin_shirley_setup(bsdf);
			}

			break;
		}
		case CLOSURE_BSDF_REFRACTION_ID:
		case CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID:
		case CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID: {
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_refractive && (path_flag & PATH_RAY_DIFFUSE))
				break;
#endif
			float3 weight = sd->svm_closure_weight * mix_weight;
			MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight);

			if(bsdf) {
				bsdf->N = N;
				bsdf->extra = NULL;

				float eta = fmaxf(param2, 1e-5f);
				eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;

				/* setup bsdf */
				if(type == CLOSURE_BSDF_REFRACTION_ID) {
					bsdf->alpha_x = 0.0f;
					bsdf->alpha_y = 0.0f;
					bsdf->ior = eta;

					sd->flag |= bsdf_refraction_setup(bsdf);
				}
				else {
					bsdf->alpha_x = param1;
					bsdf->alpha_y = param1;
					bsdf->ior = eta;

					if(type == CLOSURE_BSDF_MICROFACET_BECKMANN_REFRACTION_ID)
						sd->flag |= bsdf_microfacet_beckmann_refraction_setup(bsdf);
					else
						sd->flag |= bsdf_microfacet_ggx_refraction_setup(bsdf);
				}
			}

			break;
		}
		case CLOSURE_BSDF_SHARP_GLASS_ID:
		case CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID:
		case CLOSURE_BSDF_MICROFACET_BECKMANN_GLASS_ID: {
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_reflective &&
			   !kernel_data.integrator.caustics_refractive && (path_flag & PATH_RAY_DIFFUSE))
			{
				break;
			}
#endif
			float3 weight = sd->svm_closure_weight * mix_weight;

			/* index of refraction */
			float eta = fmaxf(param2, 1e-5f);
			eta = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;

			/* fresnel */
			float cosNO = dot(N, sd->I);
			float fresnel = fresnel_dielectric_cos(cosNO, eta);
			float roughness = param1;

			/* reflection */
#ifdef __CAUSTICS_TRICKS__
			if(kernel_data.integrator.caustics_reflective || (path_flag & PATH_RAY_DIFFUSE) == 0)
#endif
			{
				MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight*fresnel);

				if(bsdf) {
					bsdf->N = N;
					bsdf->extra = NULL;
					svm_node_glass_setup(sd, bsdf, type, eta, roughness, false);
				}
			}

			/* refraction */
#ifdef __CAUSTICS_TRICKS__
			if(kernel_data.integrator.caustics_refractive || (path_flag & PATH_RAY_DIFFUSE) == 0)
#endif
			{
				MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight*(1.0f - fresnel));

				if(bsdf) {
					bsdf->N = N;
					bsdf->extra = NULL;
					svm_node_glass_setup(sd, bsdf, type, eta, roughness, true);
				}
			}

			break;
		}
		case CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID: {
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_reflective && !kernel_data.integrator.caustics_refractive && (path_flag & PATH_RAY_DIFFUSE))
				break;
#endif
			float3 weight = sd->svm_closure_weight * mix_weight;
			MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight);
			MicrofacetExtra *extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));

			if(bsdf && extra) {
				bsdf->N = N;
				bsdf->extra = extra;
				bsdf->T = make_float3(0.0f, 0.0f, 0.0f);

				bsdf->alpha_x = param1;
				bsdf->alpha_y = param1;
				float eta = fmaxf(param2, 1e-5f);
				bsdf->ior = (sd->flag & SD_BACKFACING)? 1.0f/eta: eta;

				kernel_assert(stack_valid(data_node.z));
				bsdf->extra->color = stack_load_float3(stack, data_node.z);

				/* setup bsdf */
				sd->flag |= bsdf_microfacet_multi_ggx_glass_setup(bsdf);
			}

			break;
		}
		case CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID:
		case CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID:
		case CLOSURE_BSDF_MICROFACET_MULTI_GGX_ANISO_ID:
		case CLOSURE_BSDF_ASHIKHMIN_SHIRLEY_ANISO_ID: {
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_reflective && (path_flag & PATH_RAY_DIFFUSE))
				break;
#endif
			float3 weight = sd->svm_closure_weight * mix_weight;
			MicrofacetBsdf *bsdf = (MicrofacetBsdf*)bsdf_alloc(sd, sizeof(MicrofacetBsdf), weight);

			if(bsdf) {
				bsdf->N = N;
				bsdf->extra = NULL;
				bsdf->T = stack_load_float3(stack, data_node.y);

				/* rotate tangent */
				float rotation = stack_load_float(stack, data_node.z);

				if(rotation != 0.0f)
					bsdf->T = rotate_around_axis(bsdf->T, bsdf->N, rotation * M_2PI_F);

				/* compute roughness */
				float roughness = param1;
				float anisotropy = clamp(param2, -0.99f, 0.99f);

				if(anisotropy < 0.0f) {
					bsdf->alpha_x = roughness/(1.0f + anisotropy);
					bsdf->alpha_y = roughness*(1.0f + anisotropy);
				}
				else {
					bsdf->alpha_x = roughness*(1.0f - anisotropy);
					bsdf->alpha_y = roughness/(1.0f - anisotropy);
				}

				bsdf->ior = 0.0f;

				if(type == CLOSURE_BSDF_MICROFACET_BECKMANN_ANISO_ID) {
					sd->flag |= bsdf_microfacet_beckmann_aniso_setup(bsdf);
				}
				else if(type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID) {
					sd->flag |= bsdf_microfacet_ggx_aniso_setup(bsdf);
				}
				else if(type == CLOSURE_BSDF_MICROFACET_MULTI_GGX_ANISO_ID) {
					kernel_assert(stack_valid(data_node.w));
					bsdf->extra = (MicrofacetExtra*)closure_alloc_extra(sd, sizeof(MicrofacetExtra));
					if(bsdf->extra) {
						bsdf->extra->color = stack_load_float3(stack, data_node.w);
						sd->flag |= bsdf_microfacet_multi_ggx_aniso_setup(bsdf);
					}
				}
				else
					sd->flag |= bsdf_ashikhmin_shirley_aniso_setup(bsdf);
			}
			break;
		}
		case CLOSURE_BSDF_ASHIKHMIN_VELVET_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			VelvetBsdf *bsdf = (VelvetBsdf*)bsdf_alloc(sd, sizeof(VelvetBsdf), weight);

			if(bsdf) {
				bsdf->N = N;

				bsdf->sigma = saturate(param1);
				sd->flag |= bsdf_ashikhmin_velvet_setup(bsdf);
			}
			break;
		}
		case CLOSURE_BSDF_GLOSSY_TOON_ID:
#ifdef __CAUSTICS_TRICKS__
			if(!kernel_data.integrator.caustics_reflective && (path_flag & PATH_RAY_DIFFUSE))
				break;
#endif
		case CLOSURE_BSDF_DIFFUSE_TOON_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			ToonBsdf *bsdf = (ToonBsdf*)bsdf_alloc(sd, sizeof(ToonBsdf), weight);

			if(bsdf) {
				bsdf->N = N;
				bsdf->size = param1;
				bsdf->smooth = param2;
				
				if(type == CLOSURE_BSDF_DIFFUSE_TOON_ID)
					sd->flag |= bsdf_diffuse_toon_setup(bsdf);
				else
					sd->flag |= bsdf_glossy_toon_setup(bsdf);
			}
			break;
		}
#ifdef __HAIR__
		case CLOSURE_BSDF_HAIR_REFLECTION_ID:
		case CLOSURE_BSDF_HAIR_TRANSMISSION_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight;
			
			if(sd->flag & SD_BACKFACING && sd->type & PRIMITIVE_ALL_CURVE) {
				ShaderClosure *bsdf = bsdf_alloc(sd, sizeof(ShaderClosure), weight);

				if(bsdf) {
					/* todo: giving a fixed weight here will cause issues when
					 * mixing multiple BSDFS. energy will not be conserved and
					 * the throughput can blow up after multiple bounces. we
					 * better figure out a way to skip backfaces from rays
					 * spawned by transmission from the front */
					bsdf->weight = make_float3(1.0f, 1.0f, 1.0f);
					sd->flag |= bsdf_transparent_setup(bsdf);
				}
			}
			else {
				HairBsdf *bsdf = (HairBsdf*)bsdf_alloc(sd, sizeof(HairBsdf), weight);

				if(bsdf) {
					bsdf->roughness1 = param1;
					bsdf->roughness2 = param2;
					bsdf->offset = -stack_load_float(stack, data_node.z);

					if(stack_valid(data_node.y)) {
						bsdf->T = normalize(stack_load_float3(stack, data_node.y));
					}
					else if(!(sd->type & PRIMITIVE_ALL_CURVE)) {
						bsdf->T = normalize(sd->dPdv);
						bsdf->offset = 0.0f;
					}
					else
						bsdf->T = normalize(sd->dPdu);

					if(type == CLOSURE_BSDF_HAIR_REFLECTION_ID) {
						sd->flag |= bsdf_hair_reflection_setup(bsdf);
					}
					else {
						sd->flag |= bsdf_hair_transmission_setup(bsdf);
					}
				}
			}

			break;
		}
#endif

#ifdef __SUBSURFACE__
		case CLOSURE_BSSRDF_CUBIC_ID:
		case CLOSURE_BSSRDF_GAUSSIAN_ID:
		case CLOSURE_BSSRDF_BURLEY_ID: {
			float3 albedo = sd->svm_closure_weight;
			float3 weight = sd->svm_closure_weight * mix_weight;
			float sample_weight = fabsf(average(weight));
			
			/* disable in case of diffuse ancestor, can't see it well then and
			 * adds considerably noise due to probabilities of continuing path
			 * getting lower and lower */
			if(path_flag & PATH_RAY_DIFFUSE_ANCESTOR)
				param1 = 0.0f;

			if(sample_weight > CLOSURE_WEIGHT_CUTOFF) {
				/* radius * scale */
				float3 radius = stack_load_float3(stack, data_node.z)*param1;
				/* sharpness */
				float sharpness = stack_load_float(stack, data_node.w);
				/* texture color blur */
				float texture_blur = param2;

				/* create one closure per color channel */
				Bssrdf *bssrdf = bssrdf_alloc(sd, make_float3(weight.x, 0.0f, 0.0f));
				if(bssrdf) {
					bssrdf->sample_weight = sample_weight;
					bssrdf->radius = radius.x;
					bssrdf->texture_blur = texture_blur;
					bssrdf->albedo = albedo.x;
					bssrdf->sharpness = sharpness;
					bssrdf->N = N;
					sd->flag |= bssrdf_setup(bssrdf, (ClosureType)type);
				}

				bssrdf = bssrdf_alloc(sd, make_float3(0.0f, weight.y, 0.0f));
				if(bssrdf) {
					bssrdf->sample_weight = sample_weight;
					bssrdf->radius = radius.y;
					bssrdf->texture_blur = texture_blur;
					bssrdf->albedo = albedo.y;
					bssrdf->sharpness = sharpness;
					bssrdf->N = N;
					sd->flag |= bssrdf_setup(bssrdf, (ClosureType)type);
				}

				bssrdf = bssrdf_alloc(sd, make_float3(0.0f, 0.0f, weight.z));
				if(bssrdf) {
					bssrdf->sample_weight = sample_weight;
					bssrdf->radius = radius.z;
					bssrdf->texture_blur = texture_blur;
					bssrdf->albedo = albedo.z;
					bssrdf->sharpness = sharpness;
					bssrdf->N = N;
					sd->flag |= bssrdf_setup(bssrdf, (ClosureType)type);
				}
			}

			break;
		}
#endif
		default:
			break;
	}
}

ccl_device void svm_node_closure_volume(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int path_flag)
{
#ifdef __VOLUME__
	uint type, param1_offset, param2_offset;

	uint mix_weight_offset;
	decode_node_uchar4(node.y, &type, &param1_offset, &param2_offset, &mix_weight_offset);
	float mix_weight = (stack_valid(mix_weight_offset)? stack_load_float(stack, mix_weight_offset): 1.0f);

	if(mix_weight == 0.0f)
		return;

	float param1 = (stack_valid(param1_offset))? stack_load_float(stack, param1_offset): __uint_as_float(node.z);
	float param2 = (stack_valid(param2_offset))? stack_load_float(stack, param2_offset): __uint_as_float(node.w);
	float density = fmaxf(param1, 0.0f);

	switch(type) {
		case CLOSURE_VOLUME_ABSORPTION_ID: {
			float3 weight = (make_float3(1.0f, 1.0f, 1.0f) - sd->svm_closure_weight) * mix_weight * density;
			ShaderClosure *sc = closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_NONE_ID, weight);

			if(sc) {
				sd->flag |= volume_absorption_setup(sc);
			}
			break;
		}
		case CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID: {
			float3 weight = sd->svm_closure_weight * mix_weight * density;
			HenyeyGreensteinVolume *volume = (HenyeyGreensteinVolume*)bsdf_alloc(sd, sizeof(HenyeyGreensteinVolume), weight);

			if(volume) {
				volume->g = param2; /* g */
				sd->flag |= volume_henyey_greenstein_setup(volume);
			}
			break;
		}
		default:
			break;
	}
#endif
}

ccl_device void svm_node_closure_emission(ShaderData *sd, float *stack, uint4 node)
{
	uint mix_weight_offset = node.y;

	if(stack_valid(mix_weight_offset)) {
		float mix_weight = stack_load_float(stack, mix_weight_offset);

		if(mix_weight == 0.0f)
			return;

		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_EMISSION_ID, sd->svm_closure_weight * mix_weight);
	}
	else
		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_EMISSION_ID, sd->svm_closure_weight);

	sd->flag |= SD_EMISSION;
}

ccl_device void svm_node_closure_background(ShaderData *sd, float *stack, uint4 node)
{
	uint mix_weight_offset = node.y;

	if(stack_valid(mix_weight_offset)) {
		float mix_weight = stack_load_float(stack, mix_weight_offset);

		if(mix_weight == 0.0f)
			return;

		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_BACKGROUND_ID, sd->svm_closure_weight * mix_weight);
	}
	else
		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_BACKGROUND_ID, sd->svm_closure_weight);
}

ccl_device void svm_node_closure_holdout(ShaderData *sd, float *stack, uint4 node)
{
	uint mix_weight_offset = node.y;

	if(stack_valid(mix_weight_offset)) {
		float mix_weight = stack_load_float(stack, mix_weight_offset);

		if(mix_weight == 0.0f)
			return;

		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_HOLDOUT_ID, sd->svm_closure_weight * mix_weight);
	}
	else
		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_HOLDOUT_ID, sd->svm_closure_weight);

	sd->flag |= SD_HOLDOUT;
}

ccl_device void svm_node_closure_ambient_occlusion(ShaderData *sd, float *stack, uint4 node)
{
	uint mix_weight_offset = node.y;

	if(stack_valid(mix_weight_offset)) {
		float mix_weight = stack_load_float(stack, mix_weight_offset);

		if(mix_weight == 0.0f)
			return;

		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_AMBIENT_OCCLUSION_ID, sd->svm_closure_weight * mix_weight);
	}
	else
		closure_alloc(sd, sizeof(ShaderClosure), CLOSURE_AMBIENT_OCCLUSION_ID, sd->svm_closure_weight);

	sd->flag |= SD_AO;
}

/* Closure Nodes */

ccl_device_inline void svm_node_closure_store_weight(ShaderData *sd, float3 weight)
{
	sd->svm_closure_weight = weight;
}

ccl_device void svm_node_closure_set_weight(ShaderData *sd, uint r, uint g, uint b)
{
	float3 weight = make_float3(__uint_as_float(r), __uint_as_float(g), __uint_as_float(b));
	svm_node_closure_store_weight(sd, weight);
}

ccl_device void svm_node_closure_weight(ShaderData *sd, float *stack, uint weight_offset)
{
	float3 weight = stack_load_float3(stack, weight_offset);

	svm_node_closure_store_weight(sd, weight);
}

ccl_device void svm_node_emission_weight(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
{
	uint color_offset = node.y;
	uint strength_offset = node.z;

	float strength = stack_load_float(stack, strength_offset);
	float3 weight = stack_load_float3(stack, color_offset)*strength;

	svm_node_closure_store_weight(sd, weight);
}

ccl_device void svm_node_mix_closure(ShaderData *sd, float *stack, uint4 node)
{
	/* fetch weight from blend input, previous mix closures,
	 * and write to stack to be used by closure nodes later */
	uint weight_offset, in_weight_offset, weight1_offset, weight2_offset;
	decode_node_uchar4(node.y, &weight_offset, &in_weight_offset, &weight1_offset, &weight2_offset);

	float weight = stack_load_float(stack, weight_offset);
	weight = saturate(weight);

	float in_weight = (stack_valid(in_weight_offset))? stack_load_float(stack, in_weight_offset): 1.0f;

	if(stack_valid(weight1_offset))
		stack_store_float(stack, weight1_offset, in_weight*(1.0f - weight));
	if(stack_valid(weight2_offset))
		stack_store_float(stack, weight2_offset, in_weight*weight);
}

/* (Bump) normal */

ccl_device void svm_node_set_normal(KernelGlobals *kg, ShaderData *sd, float *stack, uint in_direction, uint out_normal)
{
	float3 normal = stack_load_float3(stack, in_direction);
	sd->N = normal;
	stack_store_float3(stack, out_normal, normal);
}

CCL_NAMESPACE_END