Merge branch 'master' into blender2.8
[blender.git] / intern / cycles / kernel / kernel_path_branched.h
index c62c3a25405179c11fc17561f49145a7ac328a5e..80fcf5b056557153e55a7b03891167cc1a5f4488 100644 (file)
@@ -48,13 +48,11 @@ ccl_device_inline void kernel_branched_path_ao(KernelGlobals *kg,
                        light_ray.P = ray_offset(sd->P, sd->Ng);
                        light_ray.D = ao_D;
                        light_ray.t = kernel_data.background.ao_distance;
-#ifdef __OBJECT_MOTION__
                        light_ray.time = sd->time;
-#endif  /* __OBJECT_MOTION__ */
                        light_ray.dP = sd->dP;
                        light_ray.dD = differential3_zero();
 
-                       if(!shadow_blocked(kg, emission_sd, state, &light_ray, &ao_shadow)) {
+                       if(!shadow_blocked(kg, sd, emission_sd, state, &light_ray, &ao_shadow)) {
                                path_radiance_accum_ao(L, state, throughput*num_samples_inv, ao_alpha, ao_bsdf, ao_shadow);
                        }
                        else {
@@ -66,6 +64,164 @@ ccl_device_inline void kernel_branched_path_ao(KernelGlobals *kg,
 
 #ifndef __SPLIT_KERNEL__
 
+#ifdef __VOLUME__
+ccl_device_forceinline void kernel_branched_path_volume(
+       KernelGlobals *kg,
+       ShaderData *sd,
+       PathState *state,
+       Ray *ray,
+       float3 *throughput,
+       ccl_addr_space Intersection *isect,
+       bool hit,
+       ShaderData *indirect_sd,
+       ShaderData *emission_sd,
+       PathRadiance *L)
+{
+       /* Sanitize volume stack. */
+       if(!hit) {
+               kernel_volume_clean_stack(kg, state->volume_stack);
+       }
+
+       if(state->volume_stack[0].shader == SHADER_NONE) {
+               return;
+       }
+
+       /* volume attenuation, emission, scatter */
+       Ray volume_ray = *ray;
+       volume_ray.t = (hit)? isect->t: FLT_MAX;
+
+       bool heterogeneous = volume_stack_is_heterogeneous(kg, state->volume_stack);
+
+#  ifdef __VOLUME_DECOUPLED__
+       /* decoupled ray marching only supported on CPU */
+       if(kernel_data.integrator.volume_decoupled) {
+               /* cache steps along volume for repeated sampling */
+               VolumeSegment volume_segment;
+
+               shader_setup_from_volume(kg, sd, &volume_ray);
+               kernel_volume_decoupled_record(kg, state,
+                       &volume_ray, sd, &volume_segment, heterogeneous);
+
+               /* direct light sampling */
+               if(volume_segment.closure_flag & SD_SCATTER) {
+                       volume_segment.sampling_method = volume_stack_sampling_method(kg, state->volume_stack);
+
+                       int all = kernel_data.integrator.sample_all_lights_direct;
+
+                       kernel_branched_path_volume_connect_light(kg, sd,
+                               emission_sd, *throughput, state, L, all,
+                               &volume_ray, &volume_segment);
+
+                       /* indirect light sampling */
+                       int num_samples = kernel_data.integrator.volume_samples;
+                       float num_samples_inv = 1.0f/num_samples;
+
+                       for(int j = 0; j < num_samples; j++) {
+                               PathState ps = *state;
+                               Ray pray = *ray;
+                               float3 tp = *throughput;
+
+                               /* branch RNG state */
+                               path_state_branch(&ps, j, num_samples);
+
+                               /* scatter sample. if we use distance sampling and take just one
+                                * sample for direct and indirect light, we could share this
+                                * computation, but makes code a bit complex */
+                               float rphase = path_state_rng_1D(kg, &ps, PRNG_PHASE_CHANNEL);
+                               float rscatter = path_state_rng_1D(kg, &ps, PRNG_SCATTER_DISTANCE);
+
+                               VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
+                                       &ps, &pray, sd, &tp, rphase, rscatter, &volume_segment, NULL, false);
+
+                               if(result == VOLUME_PATH_SCATTERED &&
+                                  kernel_path_volume_bounce(kg,
+                                                            sd,
+                                                            &tp,
+                                                            &ps,
+                                                            &L->state,
+                                                            &pray))
+                               {
+                                       kernel_path_indirect(kg,
+                                                            indirect_sd,
+                                                            emission_sd,
+                                                            &pray,
+                                                            tp*num_samples_inv,
+                                                            &ps,
+                                                            L);
+
+                                       /* for render passes, sum and reset indirect light pass variables
+                                        * for the next samples */
+                                       path_radiance_sum_indirect(L);
+                                       path_radiance_reset_indirect(L);
+                               }
+                       }
+               }
+
+               /* emission and transmittance */
+               if(volume_segment.closure_flag & SD_EMISSION)
+                       path_radiance_accum_emission(L, state, *throughput, volume_segment.accum_emission);
+               *throughput *= volume_segment.accum_transmittance;
+
+               /* free cached steps */
+               kernel_volume_decoupled_free(kg, &volume_segment);
+       }
+       else
+#  endif  /* __VOLUME_DECOUPLED__ */
+       {
+               /* GPU: no decoupled ray marching, scatter probalistically */
+               int num_samples = kernel_data.integrator.volume_samples;
+               float num_samples_inv = 1.0f/num_samples;
+
+               /* todo: we should cache the shader evaluations from stepping
+                * through the volume, for now we redo them multiple times */
+
+               for(int j = 0; j < num_samples; j++) {
+                       PathState ps = *state;
+                       Ray pray = *ray;
+                       float3 tp = (*throughput) * num_samples_inv;
+
+                       /* branch RNG state */
+                       path_state_branch(&ps, j, num_samples);
+
+                       VolumeIntegrateResult result = kernel_volume_integrate(
+                               kg, &ps, sd, &volume_ray, L, &tp, heterogeneous);
+
+#  ifdef __VOLUME_SCATTER__
+                       if(result == VOLUME_PATH_SCATTERED) {
+                               /* todo: support equiangular, MIS and all light sampling.
+                                * alternatively get decoupled ray marching working on the GPU */
+                               kernel_path_volume_connect_light(kg, sd, emission_sd, tp, state, L);
+
+                               if(kernel_path_volume_bounce(kg,
+                                                            sd,
+                                                            &tp,
+                                                            &ps,
+                                                            &L->state,
+                                                            &pray))
+                               {
+                                       kernel_path_indirect(kg,
+                                                            indirect_sd,
+                                                            emission_sd,
+                                                            &pray,
+                                                            tp,
+                                                            &ps,
+                                                            L);
+
+                                       /* for render passes, sum and reset indirect light pass variables
+                                        * for the next samples */
+                                       path_radiance_sum_indirect(L);
+                                       path_radiance_reset_indirect(L);
+                               }
+                       }
+# endif  /* __VOLUME_SCATTER__ */
+               }
+
+               /* todo: avoid this calculation using decoupled ray marching */
+               kernel_volume_shadow(kg, emission_sd, state, &volume_ray, throughput);
+       }
+}
+#endif  /* __VOLUME__ */
+
 /* bounce off surface and integrate indirect light */
 ccl_device_noinline void kernel_branched_path_surface_indirect_light(KernelGlobals *kg,
        ShaderData *sd, ShaderData *indirect_sd, ShaderData *emission_sd,
@@ -130,7 +286,7 @@ ccl_device_noinline void kernel_branched_path_surface_indirect_light(KernelGloba
                                                                num_samples,
                                                                &tp,
                                                                &ps,
-                                                               L,
+                                                               &L->state,
                                                                &bsdf_ray,
                                                                sum_sample_weight))
                        {
@@ -144,7 +300,6 @@ ccl_device_noinline void kernel_branched_path_surface_indirect_light(KernelGloba
                                             emission_sd,
                                             &bsdf_ray,
                                             tp*num_samples_inv,
-                                            num_samples,
                                             &ps,
                                             L);
 
@@ -178,23 +333,31 @@ ccl_device void kernel_branched_path_subsurface_scatter(KernelGlobals *kg,
 
                /* set up random number generator */
                uint lcg_state = lcg_state_init(state, 0x68bc21eb);
-               int num_samples = kernel_data.integrator.subsurface_samples;
+               int num_samples = kernel_data.integrator.subsurface_samples * 3;
                float num_samples_inv = 1.0f/num_samples;
                uint bssrdf_rng_hash = cmj_hash(state->rng_hash, i);
 
                /* do subsurface scatter step with copy of shader data, this will
                 * replace the BSSRDF with a diffuse BSDF closure */
                for(int j = 0; j < num_samples; j++) {
-                       SubsurfaceIntersection ss_isect;
+                       PathState hit_state = *state;
+                       path_state_branch(&hit_state, j, num_samples);
+                       hit_state.rng_hash = bssrdf_rng_hash;
+
+                       LocalIntersection ss_isect;
                        float bssrdf_u, bssrdf_v;
-                       path_branched_rng_2D(kg, bssrdf_rng_hash, state, j, num_samples, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
+                       path_state_rng_2D(kg, &hit_state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);
                        int num_hits = subsurface_scatter_multi_intersect(kg,
                                                                          &ss_isect,
                                                                          sd,
+                                                                         &hit_state,
                                                                          sc,
                                                                          &lcg_state,
                                                                          bssrdf_u, bssrdf_v,
                                                                          true);
+
+                       hit_state.rng_offset += PRNG_BOUNCE_NUM;
+
 #ifdef __VOLUME__
                        Ray volume_ray = *ray;
                        bool need_update_volume_stack =
@@ -209,14 +372,8 @@ ccl_device void kernel_branched_path_subsurface_scatter(KernelGlobals *kg,
                                                               &ss_isect,
                                                               hit,
                                                               &bssrdf_sd,
-                                                              state,
-                                                              state->flag,
-                                                              sc,
-                                                              true);
-
-                               PathState hit_state = *state;
-
-                               path_state_branch(&hit_state, j, num_samples);
+                                                              &hit_state,
+                                                              sc);
 
 #ifdef __VOLUME__
                                if(need_update_volume_stack) {
@@ -225,6 +382,10 @@ ccl_device void kernel_branched_path_subsurface_scatter(KernelGlobals *kg,
                                        volume_ray.D = normalize_len(P - volume_ray.P,
                                                                     &volume_ray.t);
 
+                                       for(int k = 0; k < VOLUME_STACK_SIZE; k++) {
+                                               hit_state.volume_stack[k] = state->volume_stack[k];
+                                       }
+
                                        kernel_volume_stack_update_for_subsurface(
                                            kg,
                                            emission_sd,
@@ -237,7 +398,7 @@ ccl_device void kernel_branched_path_subsurface_scatter(KernelGlobals *kg,
                                /* direct light */
                                if(kernel_data.integrator.use_direct_light) {
                                        int all = (kernel_data.integrator.sample_all_lights_direct) ||
-                                                 (state->flag & PATH_RAY_SHADOW_CATCHER);
+                                                 (hit_state.flag & PATH_RAY_SHADOW_CATCHER);
                                        kernel_branched_path_surface_connect_light(
                                                kg,
                                                &bssrdf_sd,
@@ -271,8 +432,7 @@ ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
                                                int sample,
                                                Ray ray,
                                                ccl_global float *buffer,
-                                               PathRadiance *L,
-                                               bool *is_shadow_catcher)
+                                               PathRadiance *L)
 {
        /* initialize */
        float3 throughput = make_float3(1.0f, 1.0f, 1.0f);
@@ -282,263 +442,65 @@ ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
        /* shader data memory used for both volumes and surfaces, saves stack space */
        ShaderData sd;
        /* shader data used by emission, shadows, volume stacks, indirect path */
-       ShaderData emission_sd, indirect_sd;
+       ShaderDataTinyStorage emission_sd_storage;
+       ShaderData *emission_sd = AS_SHADER_DATA(&emission_sd_storage);
+       ShaderData indirect_sd;
 
        PathState state;
-       path_state_init(kg, &emission_sd, &state, rng_hash, sample, &ray);
+       path_state_init(kg, emission_sd, &state, rng_hash, sample, &ray);
 
        /* Main Loop
         * Here we only handle transparency intersections from the camera ray.
         * Indirect bounces are handled in kernel_branched_path_surface_indirect_light().
         */
        for(;;) {
-               /* intersect scene */
+               /* Find intersection with objects in scene. */
                Intersection isect;
-               uint visibility = path_state_ray_visibility(kg, &state);
-
-#ifdef __HAIR__
-               float difl = 0.0f, extmax = 0.0f;
-               uint lcg_state = 0;
-
-               if(kernel_data.bvh.have_curves) {
-                       if(kernel_data.cam.resolution == 1) {
-                               float3 pixdiff = ray.dD.dx + ray.dD.dy;
-                               /*pixdiff = pixdiff - dot(pixdiff, ray.D)*ray.D;*/
-                               difl = kernel_data.curve.minimum_width * len(pixdiff) * 0.5f;
-                       }
-
-                       extmax = kernel_data.curve.maximum_width;
-                       lcg_state = lcg_state_init(&state, 0x51633e2d);
-               }
-
-               bool hit = scene_intersect(kg, ray, visibility, &isect, &lcg_state, difl, extmax);
-#else
-               bool hit = scene_intersect(kg, ray, visibility, &isect, NULL, 0.0f, 0.0f);
-#endif  /* __HAIR__ */
-
-#ifdef __KERNEL_DEBUG__
-               L->debug_data.num_bvh_traversed_nodes += isect.num_traversed_nodes;
-               L->debug_data.num_bvh_traversed_instances += isect.num_traversed_instances;
-               L->debug_data.num_bvh_intersections += isect.num_intersections;
-               L->debug_data.num_ray_bounces++;
-#endif  /* __KERNEL_DEBUG__ */
+               bool hit = kernel_path_scene_intersect(kg, &state, &ray, &isect, L);
 
 #ifdef __VOLUME__
-               /* Sanitize volume stack. */
-               if(!hit) {
-                       kernel_volume_clean_stack(kg, state.volume_stack);
-               }
-               /* volume attenuation, emission, scatter */
-               if(state.volume_stack[0].shader != SHADER_NONE) {
-                       Ray volume_ray = ray;
-                       volume_ray.t = (hit)? isect.t: FLT_MAX;
-                       
-                       bool heterogeneous = volume_stack_is_heterogeneous(kg, state.volume_stack);
-
-#ifdef __VOLUME_DECOUPLED__
-                       /* decoupled ray marching only supported on CPU */
-
-                       /* cache steps along volume for repeated sampling */
-                       VolumeSegment volume_segment;
-
-                       shader_setup_from_volume(kg, &sd, &volume_ray);
-                       kernel_volume_decoupled_record(kg, &state,
-                               &volume_ray, &sd, &volume_segment, heterogeneous);
-
-                       /* direct light sampling */
-                       if(volume_segment.closure_flag & SD_SCATTER) {
-                               volume_segment.sampling_method = volume_stack_sampling_method(kg, state.volume_stack);
-
-                               int all = kernel_data.integrator.sample_all_lights_direct;
-
-                               kernel_branched_path_volume_connect_light(kg, &sd,
-                                       &emission_sd, throughput, &state, L, all,
-                                       &volume_ray, &volume_segment);
-
-                               /* indirect light sampling */
-                               int num_samples = kernel_data.integrator.volume_samples;
-                               float num_samples_inv = 1.0f/num_samples;
-
-                               for(int j = 0; j < num_samples; j++) {
-                                       PathState ps = state;
-                                       Ray pray = ray;
-                                       float3 tp = throughput;
-
-                                       /* branch RNG state */
-                                       path_state_branch(&ps, j, num_samples);
-
-                                       /* scatter sample. if we use distance sampling and take just one
-                                        * sample for direct and indirect light, we could share this
-                                        * computation, but makes code a bit complex */
-                                       float rphase = path_state_rng_1D_for_decision(kg, &ps, PRNG_PHASE);
-                                       float rscatter = path_state_rng_1D_for_decision(kg, &ps, PRNG_SCATTER_DISTANCE);
-
-                                       VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
-                                               &ps, &pray, &sd, &tp, rphase, rscatter, &volume_segment, NULL, false);
-
-                                       (void)result;
-                                       kernel_assert(result == VOLUME_PATH_SCATTERED);
-
-                                       if(kernel_path_volume_bounce(kg,
-                                                                    &sd,
-                                                                    &tp,
-                                                                    &ps,
-                                                                    L,
-                                                                    &pray))
-                                       {
-                                               kernel_path_indirect(kg,
-                                                                    &indirect_sd,
-                                                                    &emission_sd,
-                                                                    &pray,
-                                                                    tp*num_samples_inv,
-                                                                    num_samples,
-                                                                    &ps,
-                                                                    L);
-
-                                               /* for render passes, sum and reset indirect light pass variables
-                                                * for the next samples */
-                                               path_radiance_sum_indirect(L);
-                                               path_radiance_reset_indirect(L);
-                                       }
-                               }
-                       }
-
-                       /* emission and transmittance */
-                       if(volume_segment.closure_flag & SD_EMISSION)
-                               path_radiance_accum_emission(L, throughput, volume_segment.accum_emission, state.bounce);
-                       throughput *= volume_segment.accum_transmittance;
-
-                       /* free cached steps */
-                       kernel_volume_decoupled_free(kg, &volume_segment);
-#else
-                       /* GPU: no decoupled ray marching, scatter probalistically */
-                       int num_samples = kernel_data.integrator.volume_samples;
-                       float num_samples_inv = 1.0f/num_samples;
-
-                       /* todo: we should cache the shader evaluations from stepping
-                        * through the volume, for now we redo them multiple times */
-
-                       for(int j = 0; j < num_samples; j++) {
-                               PathState ps = state;
-                               Ray pray = ray;
-                               float3 tp = throughput * num_samples_inv;
-
-                               /* branch RNG state */
-                               path_state_branch(&ps, j, num_samples);
-
-                               VolumeIntegrateResult result = kernel_volume_integrate(
-                                       kg, &ps, &sd, &volume_ray, L, &tp, heterogeneous);
-
-#ifdef __VOLUME_SCATTER__
-                               if(result == VOLUME_PATH_SCATTERED) {
-                                       /* todo: support equiangular, MIS and all light sampling.
-                                        * alternatively get decoupled ray marching working on the GPU */
-                                       kernel_path_volume_connect_light(kg, &sd, &emission_sd, tp, &state, L);
-
-                                       if(kernel_path_volume_bounce(kg,
-                                                                    &sd,
-                                                                    &tp,
-                                                                    &ps,
-                                                                    L,
-                                                                    &pray))
-                                       {
-                                               kernel_path_indirect(kg,
-                                                                    &indirect_sd,
-                                                                    &emission_sd,
-                                                                    &pray,
-                                                                    tp,
-                                                                    num_samples,
-                                                                    &ps,
-                                                                    L);
-
-                                               /* for render passes, sum and reset indirect light pass variables
-                                                * for the next samples */
-                                               path_radiance_sum_indirect(L);
-                                               path_radiance_reset_indirect(L);
-                                       }
-                               }
-#endif  /* __VOLUME_SCATTER__ */
-                       }
-
-                       /* todo: avoid this calculation using decoupled ray marching */
-                       kernel_volume_shadow(kg, &emission_sd, &state, &volume_ray, &throughput);
-#endif  /* __VOLUME_DECOUPLED__ */
-               }
+               /* Volume integration. */
+               kernel_branched_path_volume(kg,
+                                           &sd,
+                                           &state,
+                                           &ray,
+                                           &throughput,
+                                           &isect,
+                                           hit,
+                                           &indirect_sd,
+                                           emission_sd,
+                                           L);
 #endif  /* __VOLUME__ */
 
+               /* Shade background. */
                if(!hit) {
-                       /* eval background shader if nothing hit */
-                       if(kernel_data.background.transparent) {
-                               L->transparent += average(throughput);
-
-#ifdef __PASSES__
-                               if(!(kernel_data.film.pass_flag & PASS_BACKGROUND))
-#endif  /* __PASSES__ */
-                                       break;
-                       }
-
-#ifdef __BACKGROUND__
-                       /* sample background shader */
-                       float3 L_background = indirect_background(kg, &emission_sd, &state, &ray);
-                       path_radiance_accum_background(L, &state, throughput, L_background);
-#endif  /* __BACKGROUND__ */
-
+                       kernel_path_background(kg, &state, &ray, throughput, &sd, L);
                        break;
                }
 
-               /* setup shading */
+               /* Setup and evaluate shader. */
                shader_setup_from_ray(kg, &sd, &isect, &ray);
-               shader_eval_surface(kg, &sd, &state, 0.0f, state.flag);
-               shader_merge_closures(&sd);
 
-#ifdef __SHADOW_TRICKS__
-               if((sd.object_flag & SD_OBJECT_SHADOW_CATCHER)) {
-                       state.flag |= (PATH_RAY_SHADOW_CATCHER |
-                                      PATH_RAY_STORE_SHADOW_INFO);
-                       if(!kernel_data.background.transparent) {
-                               L->shadow_background_color =
-                                       indirect_background(kg, &emission_sd, &state, &ray);
-                       }
-                       L->shadow_radiance_sum = path_radiance_clamp_and_sum(kg, L);
-                       L->shadow_throughput = average(throughput);
-               }
-               else if(state.flag & PATH_RAY_SHADOW_CATCHER) {
-                       /* Only update transparency after shadow catcher bounce. */
-                       L->shadow_transparency *=
-                               average(shader_bsdf_transparency(kg, &sd));
-               }
-#endif  /* __SHADOW_TRICKS__ */
-
-               /* holdout */
-#ifdef __HOLDOUT__
-               if((sd.flag & SD_HOLDOUT) || (sd.object_flag & SD_OBJECT_HOLDOUT_MASK)) {
-                       if(kernel_data.background.transparent) {
-                               float3 holdout_weight;
-                               if(sd.object_flag & SD_OBJECT_HOLDOUT_MASK) {
-                                       holdout_weight = make_float3(1.0f, 1.0f, 1.0f);
-                               }
-                               else {
-                                       holdout_weight = shader_holdout_eval(kg, &sd);
-                               }
-                               /* any throughput is ok, should all be identical here */
-                               L->transparent += average(holdout_weight*throughput);
-                       }
-                       if(sd.object_flag & SD_OBJECT_HOLDOUT_MASK) {
-                               break;
-                       }
-               }
-#endif  /* __HOLDOUT__ */
+               /* Skip most work for volume bounding surface. */
+#ifdef __VOLUME__
+               if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
+#endif
 
-               /* holdout mask objects do not write data passes */
-               kernel_write_data_passes(kg, buffer, L, &sd, sample, &state, throughput);
+               shader_eval_surface(kg, &sd, &state, state.flag);
+               shader_merge_closures(&sd);
 
-#ifdef __EMISSION__
-               /* emission */
-               if(sd.flag & SD_EMISSION) {
-                       float3 emission = indirect_primitive_emission(kg, &sd, isect.t, state.flag, state.ray_pdf);
-                       path_radiance_accum_emission(L, throughput, emission, state.bounce);
+               /* Apply shadow catcher, holdout, emission. */
+               if(!kernel_path_shader_apply(kg,
+                                            &sd,
+                                            &state,
+                                            &ray,
+                                            throughput,
+                                            emission_sd,
+                                            L,
+                                            buffer))
+               {
+                       break;
                }
-#endif  /* __EMISSION__ */
 
                /* transparency termination */
                if(state.flag & PATH_RAY_TRANSPARENT) {
@@ -551,7 +513,7 @@ ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
                                break;
                        }
                        else if(probability != 1.0f) {
-                               float terminate = path_state_rng_1D_for_decision(kg, &state, PRNG_TERMINATE);
+                               float terminate = path_state_rng_1D(kg, &state, PRNG_TERMINATE);
 
                                if(terminate >= probability)
                                        break;
@@ -564,51 +526,56 @@ ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
 
 #ifdef __AO__
                /* ambient occlusion */
-               if(kernel_data.integrator.use_ambient_occlusion || (sd.flag & SD_AO)) {
-                       kernel_branched_path_ao(kg, &sd, &emission_sd, L, &state, throughput);
+               if(kernel_data.integrator.use_ambient_occlusion) {
+                       kernel_branched_path_ao(kg, &sd, emission_sd, L, &state, throughput);
                }
 #endif  /* __AO__ */
 
 #ifdef __SUBSURFACE__
                /* bssrdf scatter to a different location on the same object */
                if(sd.flag & SD_BSSRDF) {
-                       kernel_branched_path_subsurface_scatter(kg, &sd, &indirect_sd, &emission_sd,
+                       kernel_branched_path_subsurface_scatter(kg, &sd, &indirect_sd, emission_sd,
                                                                L, &state, &ray, throughput);
                }
 #endif  /* __SUBSURFACE__ */
 
-               if(!(sd.flag & SD_HAS_ONLY_VOLUME)) {
-                       PathState hit_state = state;
+               PathState hit_state = state;
 
 #ifdef __EMISSION__
-                       /* direct light */
-                       if(kernel_data.integrator.use_direct_light) {
-                               int all = (kernel_data.integrator.sample_all_lights_direct) ||
-                                         (state.flag & PATH_RAY_SHADOW_CATCHER);
-                               kernel_branched_path_surface_connect_light(kg,
-                                       &sd, &emission_sd, &hit_state, throughput, 1.0f, L, all);
-                       }
+               /* direct light */
+               if(kernel_data.integrator.use_direct_light) {
+                       int all = (kernel_data.integrator.sample_all_lights_direct) ||
+                                         (state.flag & PATH_RAY_SHADOW_CATCHER);
+                       kernel_branched_path_surface_connect_light(kg,
+                               &sd, emission_sd, &hit_state, throughput, 1.0f, L, all);
+               }
 #endif  /* __EMISSION__ */
 
-                       /* indirect light */
-                       kernel_branched_path_surface_indirect_light(kg,
-                               &sd, &indirect_sd, &emission_sd, throughput, 1.0f, &hit_state, L);
+               /* indirect light */
+               kernel_branched_path_surface_indirect_light(kg,
+                       &sd, &indirect_sd, emission_sd, throughput, 1.0f, &hit_state, L);
 
-                       /* continue in case of transparency */
-                       throughput *= shader_bsdf_transparency(kg, &sd);
+               /* continue in case of transparency */
+               throughput *= shader_bsdf_transparency(kg, &sd);
 
-                       if(is_zero(throughput))
-                               break;
-               }
+               if(is_zero(throughput))
+                       break;
 
                /* Update Path State */
-               state.flag |= PATH_RAY_TRANSPARENT;
-               state.transparent_bounce++;
+               path_state_next(kg, &state, LABEL_TRANSPARENT);
+
+#ifdef __VOLUME__
+               }
+               else {
+                       if(!path_state_volume_next(kg, &state)) {
+                               break;
+                       }
+               }
+#endif
 
                ray.P = ray_offset(sd.P, -sd.Ng);
                ray.t -= sd.ray_length; /* clipping works through transparent */
 
-
 #ifdef __RAY_DIFFERENTIALS__
                ray.dP = sd.dP;
                ray.dD.dx = -sd.dI.dx;
@@ -620,39 +587,30 @@ ccl_device void kernel_branched_path_integrate(KernelGlobals *kg,
                kernel_volume_stack_enter_exit(kg, &sd, state.volume_stack);
 #endif  /* __VOLUME__ */
        }
-
-#ifdef __SHADOW_TRICKS__
-       *is_shadow_catcher = (state.flag & PATH_RAY_SHADOW_CATCHER) != 0;
-#endif  /* __SHADOW_TRICKS__ */
 }
 
 ccl_device void kernel_branched_path_trace(KernelGlobals *kg,
-       ccl_global float *buffer, ccl_global uint *rng_state,
+       ccl_global float *buffer,
        int sample, int x, int y, int offset, int stride)
 {
        /* buffer offset */
        int index = offset + x + y*stride;
        int pass_stride = kernel_data.film.pass_stride;
 
-       rng_state += index;
        buffer += index*pass_stride;
 
        /* initialize random numbers and ray */
        uint rng_hash;
        Ray ray;
 
-       kernel_path_trace_setup(kg, rng_state, sample, x, y, &rng_hash, &ray);
+       kernel_path_trace_setup(kg, sample, x, y, &rng_hash, &ray);
 
        /* integrate */
        PathRadiance L;
-       bool is_shadow_catcher;
 
        if(ray.t != 0.0f) {
-               kernel_branched_path_integrate(kg, rng_hash, sample, ray, buffer, &L, &is_shadow_catcher);
-               kernel_write_result(kg, buffer, sample, &L, is_shadow_catcher);
-       }
-       else {
-               kernel_write_result(kg, buffer, sample, NULL, false);
+               kernel_branched_path_integrate(kg, rng_hash, sample, ray, buffer, &L);
+               kernel_write_result(kg, buffer, sample, &L);
        }
 }