Cycles: merge of cycles-x branch, a major update to the renderer

This includes much improved GPU rendering performance, viewport interactivity,
new shadow catcher, revamped sampling settings, subsurface scattering anisotropy,
new GPU volume sampling, improved PMJ sampling pattern, and more.

Some features have also been removed or changed, breaking backwards compatibility.
Including the removal of the OpenCL backend, for which alternatives are under
development.

Release notes and code docs:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles
https://wiki.blender.org/wiki/Source/Render/Cycles

Credits:
* Sergey Sharybin
* Brecht Van Lommel
* Patrick Mours (OptiX backend)
* Christophe Hery (subsurface scattering anisotropy)
* William Leeson (PMJ sampling pattern)
* Alaska (various fixes and tweaks)
* Thomas Dinges (various fixes)

For the full commit history, see the cycles-x branch. This squashes together
all the changes since intermediate changes would often fail building or tests.

Ref T87839, T87837, T87836
Fixes T90734, T89353, T80267, T80267, T77185, T69800

1 files changed, 0 insertions, 260 deletions

diff --git a/intern/cycles/kernel/kernel_path_volume.h b/intern/cycles/kernel/kernel_path_volume.h
deleted file mode 100644
index a787910e65c..00000000000
--- a/intern/cycles/kernel/kernel_path_volume.h
+++ /dev/null
@@ -1,260 +0,0 @@
-/*
- * 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
-
-#ifdef __VOLUME_SCATTER__
-
-ccl_device_inline void kernel_path_volume_connect_light(KernelGlobals *kg,
-                                                        ShaderData *sd,
-                                                        ShaderData *emission_sd,
-                                                        float3 throughput,
-                                                        ccl_addr_space PathState *state,
-                                                        PathRadiance *L)
-{
-#  ifdef __EMISSION__
-  /* sample illumination from lights to find path contribution */
-  Ray light_ray ccl_optional_struct_init;
-  BsdfEval L_light ccl_optional_struct_init;
-  bool is_lamp = false;
-  bool has_emission = false;
-
-  light_ray.t = 0.0f;
-#    ifdef __OBJECT_MOTION__
-  /* connect to light from given point where shader has been evaluated */
-  light_ray.time = sd->time;
-#    endif
-
-  if (kernel_data.integrator.use_direct_light) {
-    float light_u, light_v;
-    path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v);
-
-    LightSample ls ccl_optional_struct_init;
-    if (light_sample(kg, -1, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
-      float terminate = path_state_rng_light_termination(kg, state);
-      has_emission = direct_emission(
-          kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate);
-    }
-  }
-
-  /* trace shadow ray */
-  float3 shadow;
-
-  const bool blocked = shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow);
-
-  if (has_emission && !blocked) {
-    /* accumulate */
-    path_radiance_accum_light(kg, L, state, throughput, &L_light, shadow, 1.0f, is_lamp);
-  }
-#  endif /* __EMISSION__ */
-}
-
-ccl_device_noinline_cpu bool kernel_path_volume_bounce(KernelGlobals *kg,
-                                                       ShaderData *sd,
-                                                       ccl_addr_space float3 *throughput,
-                                                       ccl_addr_space PathState *state,
-                                                       PathRadianceState *L_state,
-                                                       ccl_addr_space Ray *ray)
-{
-  /* sample phase function */
-  float phase_pdf;
-  BsdfEval phase_eval ccl_optional_struct_init;
-  float3 phase_omega_in ccl_optional_struct_init;
-  differential3 phase_domega_in ccl_optional_struct_init;
-  float phase_u, phase_v;
-  path_state_rng_2D(kg, state, PRNG_BSDF_U, &phase_u, &phase_v);
-  int label;
-
-  label = shader_volume_phase_sample(
-      kg, sd, phase_u, phase_v, &phase_eval, &phase_omega_in, &phase_domega_in, &phase_pdf);
-
-  if (phase_pdf == 0.0f || bsdf_eval_is_zero(&phase_eval))
-    return false;
-
-  /* modify throughput */
-  path_radiance_bsdf_bounce(kg, L_state, throughput, &phase_eval, phase_pdf, state->bounce, label);
-
-  /* set labels */
-  state->ray_pdf = phase_pdf;
-#  ifdef __LAMP_MIS__
-  state->ray_t = 0.0f;
-#  endif
-  state->min_ray_pdf = fminf(phase_pdf, state->min_ray_pdf);
-
-  /* update path state */
-  path_state_next(kg, state, label);
-
-  /* Russian roulette termination of volume ray scattering. */
-  float probability = path_state_continuation_probability(kg, state, *throughput);
-
-  if (probability == 0.0f) {
-    return false;
-  }
-  else if (probability != 1.0f) {
-    /* Use dimension from the previous bounce, has not been used yet. */
-    float terminate = path_state_rng_1D(kg, state, PRNG_TERMINATE - PRNG_BOUNCE_NUM);
-
-    if (terminate >= probability) {
-      return false;
-    }
-
-    *throughput /= probability;
-  }
-
-  /* setup ray */
-  ray->P = sd->P;
-  ray->D = phase_omega_in;
-  ray->t = FLT_MAX;
-
-#  ifdef __RAY_DIFFERENTIALS__
-  ray->dP = sd->dP;
-  ray->dD = phase_domega_in;
-#  endif
-
-  return true;
-}
-
-#  if !defined(__SPLIT_KERNEL__) && (defined(__BRANCHED_PATH__) || defined(__VOLUME_DECOUPLED__))
-ccl_device void kernel_branched_path_volume_connect_light(KernelGlobals *kg,
-                                                          ShaderData *sd,
-                                                          ShaderData *emission_sd,
-                                                          float3 throughput,
-                                                          ccl_addr_space PathState *state,
-                                                          PathRadiance *L,
-                                                          bool sample_all_lights,
-                                                          Ray *ray,
-                                                          const VolumeSegment *segment)
-{
-#    ifdef __EMISSION__
-  BsdfEval L_light ccl_optional_struct_init;
-
-  int num_lights = 1;
-  if (sample_all_lights) {
-    num_lights = kernel_data.integrator.num_all_lights;
-    if (kernel_data.integrator.pdf_triangles != 0.0f) {
-      num_lights += 1;
-    }
-  }
-
-  for (int i = 0; i < num_lights; ++i) {
-    /* sample one light at random */
-    int num_samples = 1;
-    int num_all_lights = 1;
-    uint lamp_rng_hash = state->rng_hash;
-    bool double_pdf = false;
-    bool is_mesh_light = false;
-    bool is_lamp = false;
-
-    if (sample_all_lights) {
-      /* lamp sampling */
-      is_lamp = i < kernel_data.integrator.num_all_lights;
-      if (is_lamp) {
-        if (UNLIKELY(light_select_reached_max_bounces(kg, i, state->bounce))) {
-          continue;
-        }
-        num_samples = light_select_num_samples(kg, i);
-        num_all_lights = kernel_data.integrator.num_all_lights;
-        lamp_rng_hash = cmj_hash(state->rng_hash, i);
-        double_pdf = kernel_data.integrator.pdf_triangles != 0.0f;
-      }
-      /* mesh light sampling */
-      else {
-        num_samples = kernel_data.integrator.mesh_light_samples;
-        double_pdf = kernel_data.integrator.num_all_lights != 0;
-        is_mesh_light = true;
-      }
-    }
-
-    float num_samples_inv = 1.0f / (num_samples * num_all_lights);
-
-    for (int j = 0; j < num_samples; j++) {
-      Ray light_ray ccl_optional_struct_init;
-      light_ray.t = 0.0f; /* reset ray */
-#      ifdef __OBJECT_MOTION__
-      light_ray.time = sd->time;
-#      endif
-      bool has_emission = false;
-
-      float3 tp = throughput;
-
-      if (kernel_data.integrator.use_direct_light) {
-        /* sample random position on random light/triangle */
-        float light_u, light_v;
-        path_branched_rng_2D(
-            kg, lamp_rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v);
-
-        /* only sample triangle lights */
-        if (is_mesh_light && double_pdf) {
-          light_u = 0.5f * light_u;
-        }
-
-        LightSample ls ccl_optional_struct_init;
-        const int lamp = is_lamp ? i : -1;
-        light_sample(kg, lamp, light_u, light_v, sd->time, ray->P, state->bounce, &ls);
-
-        /* sample position on volume segment */
-        float rphase = path_branched_rng_1D(
-            kg, state->rng_hash, state, j, num_samples, PRNG_PHASE_CHANNEL);
-        float rscatter = path_branched_rng_1D(
-            kg, state->rng_hash, state, j, num_samples, PRNG_SCATTER_DISTANCE);
-
-        VolumeIntegrateResult result = kernel_volume_decoupled_scatter(kg,
-                                                                       state,
-                                                                       ray,
-                                                                       sd,
-                                                                       &tp,
-                                                                       rphase,
-                                                                       rscatter,
-                                                                       segment,
-                                                                       (ls.t != FLT_MAX) ? &ls.P :
-                                                                                           NULL,
-                                                                       false);
-
-        if (result == VOLUME_PATH_SCATTERED) {
-          /* todo: split up light_sample so we don't have to call it again with new position */
-          if (light_sample(kg, lamp, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) {
-            if (double_pdf) {
-              ls.pdf *= 2.0f;
-            }
-
-            /* sample random light */
-            float terminate = path_branched_rng_light_termination(
-                kg, state->rng_hash, state, j, num_samples);
-            has_emission = direct_emission(
-                kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate);
-          }
-        }
-      }
-
-      /* trace shadow ray */
-      float3 shadow;
-
-      const bool blocked = shadow_blocked(kg, sd, emission_sd, state, &light_ray, &shadow);
-
-      if (has_emission && !blocked) {
-        /* accumulate */
-        path_radiance_accum_light(
-            kg, L, state, tp * num_samples_inv, &L_light, shadow, num_samples_inv, is_lamp);
-      }
-    }
-  }
-#    endif /* __EMISSION__ */
-}
-#  endif /* __SPLIT_KERNEL__ */
-
-#endif /* __VOLUME_SCATTER__ */
-
-CCL_NAMESPACE_END