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, 38 insertions, 12 deletions

diff --git a/intern/cycles/kernel/svm/svm_light_path.h b/intern/cycles/kernel/svm/svm_light_path.h
index 768c65918cd..49fabad1cc5 100644
--- a/intern/cycles/kernel/svm/svm_light_path.h
+++ b/intern/cycles/kernel/svm/svm_light_path.h
@@ -18,12 +18,12 @@ CCL_NAMESPACE_BEGIN
 
 /* Light Path Node */
 
-ccl_device void svm_node_light_path(ShaderData *sd,
-                                    ccl_addr_space PathState *state,
-                                    float *stack,
-                                    uint type,
-                                    uint out_offset,
-                                    int path_flag)
+ccl_device_noinline void svm_node_light_path(INTEGRATOR_STATE_CONST_ARGS,
+                                             const ShaderData *sd,
+                                             float *stack,
+                                             uint type,
+                                             uint out_offset,
+                                             int path_flag)
 {
   float info = 0.0f;
 
@@ -58,21 +58,47 @@ ccl_device void svm_node_light_path(ShaderData *sd,
     case NODE_LP_ray_length:
       info = sd->ray_length;
       break;
-    case NODE_LP_ray_depth:
-      info = (float)state->bounce;
+    case NODE_LP_ray_depth: {
+      /* Read bounce from difference location depending if this is a shadow
+       * path. It's a bit dubious to have integrate state details leak into
+       * this function but hard to avoid currently. */
+      int bounce = (INTEGRATOR_STATE_IS_NULL)    ? 0 :
+                   (path_flag & PATH_RAY_SHADOW) ? INTEGRATOR_STATE(shadow_path, bounce) :
+                                                   INTEGRATOR_STATE(path, bounce);
+
+      /* For background, light emission and shadow evaluation we from a
+       * surface or volume we are effective one bounce further. */
+      if (path_flag & (PATH_RAY_SHADOW | PATH_RAY_EMISSION)) {
+        bounce++;
+      }
+
+      info = (float)bounce;
       break;
+    }
+      /* TODO */
+    case NODE_LP_ray_transparent: {
+      const int bounce = (INTEGRATOR_STATE_IS_NULL) ?
+                             0 :
+                         (path_flag & PATH_RAY_SHADOW) ?
+                             INTEGRATOR_STATE(shadow_path, transparent_bounce) :
+                             INTEGRATOR_STATE(path, transparent_bounce);
+
+      info = (float)bounce;
+      break;
+    }
+#if 0
     case NODE_LP_ray_diffuse:
       info = (float)state->diffuse_bounce;
       break;
     case NODE_LP_ray_glossy:
       info = (float)state->glossy_bounce;
       break;
-    case NODE_LP_ray_transparent:
-      info = (float)state->transparent_bounce;
-      break;
+#endif
+#if 0
     case NODE_LP_ray_transmission:
       info = (float)state->transmission_bounce;
       break;
+#endif
   }
 
   stack_store_float(stack, out_offset, info);
@@ -80,7 +106,7 @@ ccl_device void svm_node_light_path(ShaderData *sd,
 
 /* Light Falloff Node */
 
-ccl_device void svm_node_light_falloff(ShaderData *sd, float *stack, uint4 node)
+ccl_device_noinline void svm_node_light_falloff(ShaderData *sd, float *stack, uint4 node)
 {
   uint strength_offset, out_offset, smooth_offset;