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, 42 deletions

diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 795166bcf4c..5303d55242e 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -2736,18 +2736,21 @@ NODE_DEFINE(PrincipledBsdfNode)
       distribution, "Distribution", distribution_enum, CLOSURE_BSDF_MICROFACET_MULTI_GGX_GLASS_ID);
 
   static NodeEnum subsurface_method_enum;
-  subsurface_method_enum.insert("burley", CLOSURE_BSSRDF_PRINCIPLED_ID);
-  subsurface_method_enum.insert("random_walk", CLOSURE_BSSRDF_PRINCIPLED_RANDOM_WALK_ID);
+  subsurface_method_enum.insert("random_walk_fixed_radius",
+                                CLOSURE_BSSRDF_RANDOM_WALK_FIXED_RADIUS_ID);
+  subsurface_method_enum.insert("random_walk", CLOSURE_BSSRDF_RANDOM_WALK_ID);
   SOCKET_ENUM(subsurface_method,
               "Subsurface Method",
               subsurface_method_enum,
-              CLOSURE_BSSRDF_PRINCIPLED_ID);
+              CLOSURE_BSSRDF_RANDOM_WALK_ID);
 
   SOCKET_IN_COLOR(base_color, "Base Color", make_float3(0.8f, 0.8f, 0.8f));
   SOCKET_IN_COLOR(subsurface_color, "Subsurface Color", make_float3(0.8f, 0.8f, 0.8f));
   SOCKET_IN_FLOAT(metallic, "Metallic", 0.0f);
   SOCKET_IN_FLOAT(subsurface, "Subsurface", 0.0f);
   SOCKET_IN_VECTOR(subsurface_radius, "Subsurface Radius", make_float3(0.1f, 0.1f, 0.1f));
+  SOCKET_IN_FLOAT(subsurface_ior, "Subsurface IOR", 1.4f);
+  SOCKET_IN_FLOAT(subsurface_anisotropy, "Subsurface Anisotropy", 0.0f);
   SOCKET_IN_FLOAT(specular, "Specular", 0.0f);
   SOCKET_IN_FLOAT(roughness, "Roughness", 0.5f);
   SOCKET_IN_FLOAT(specular_tint, "Specular Tint", 0.0f);
@@ -2857,6 +2860,8 @@ void PrincipledBsdfNode::compile(SVMCompiler &compiler,
                                  ShaderInput *p_metallic,
                                  ShaderInput *p_subsurface,
                                  ShaderInput *p_subsurface_radius,
+                                 ShaderInput *p_subsurface_ior,
+                                 ShaderInput *p_subsurface_anisotropy,
                                  ShaderInput *p_specular,
                                  ShaderInput *p_roughness,
                                  ShaderInput *p_specular_tint,
@@ -2896,6 +2901,8 @@ void PrincipledBsdfNode::compile(SVMCompiler &compiler,
   int transmission_roughness_offset = compiler.stack_assign(p_transmission_roughness);
   int anisotropic_rotation_offset = compiler.stack_assign(p_anisotropic_rotation);
   int subsurface_radius_offset = compiler.stack_assign(p_subsurface_radius);
+  int subsurface_ior_offset = compiler.stack_assign(p_subsurface_ior);
+  int subsurface_anisotropy_offset = compiler.stack_assign(p_subsurface_anisotropy);
 
   compiler.add_node(NODE_CLOSURE_BSDF,
                     compiler.encode_uchar4(closure,
@@ -2929,8 +2936,10 @@ void PrincipledBsdfNode::compile(SVMCompiler &compiler,
       __float_as_int(bc_default.y),
       __float_as_int(bc_default.z));
 
-  compiler.add_node(
-      clearcoat_normal_offset, subsurface_radius_offset, SVM_STACK_INVALID, SVM_STACK_INVALID);
+  compiler.add_node(clearcoat_normal_offset,
+                    subsurface_radius_offset,
+                    subsurface_ior_offset,
+                    subsurface_anisotropy_offset);
 
   float3 ss_default = get_float3(subsurface_color_in->socket_type);
 
@@ -2953,6 +2962,8 @@ void PrincipledBsdfNode::compile(SVMCompiler &compiler)
           input("Metallic"),
           input("Subsurface"),
           input("Subsurface Radius"),
+          input("Subsurface IOR"),
+          input("Subsurface Anisotropy"),
           input("Specular"),
           input("Roughness"),
           input("Specular Tint"),
@@ -3048,16 +3059,16 @@ NODE_DEFINE(SubsurfaceScatteringNode)
   SOCKET_IN_NORMAL(normal, "Normal", zero_float3(), SocketType::LINK_NORMAL);
   SOCKET_IN_FLOAT(surface_mix_weight, "SurfaceMixWeight", 0.0f, SocketType::SVM_INTERNAL);
 
-  static NodeEnum falloff_enum;
-  falloff_enum.insert("cubic", CLOSURE_BSSRDF_CUBIC_ID);
-  falloff_enum.insert("gaussian", CLOSURE_BSSRDF_GAUSSIAN_ID);
-  falloff_enum.insert("burley", CLOSURE_BSSRDF_BURLEY_ID);
-  falloff_enum.insert("random_walk", CLOSURE_BSSRDF_RANDOM_WALK_ID);
-  SOCKET_ENUM(falloff, "Falloff", falloff_enum, CLOSURE_BSSRDF_BURLEY_ID);
+  static NodeEnum method_enum;
+  method_enum.insert("random_walk_fixed_radius", CLOSURE_BSSRDF_RANDOM_WALK_FIXED_RADIUS_ID);
+  method_enum.insert("random_walk", CLOSURE_BSSRDF_RANDOM_WALK_ID);
+  SOCKET_ENUM(method, "Method", method_enum, CLOSURE_BSSRDF_RANDOM_WALK_ID);
+
   SOCKET_IN_FLOAT(scale, "Scale", 0.01f);
   SOCKET_IN_VECTOR(radius, "Radius", make_float3(0.1f, 0.1f, 0.1f));
-  SOCKET_IN_FLOAT(sharpness, "Sharpness", 0.0f);
-  SOCKET_IN_FLOAT(texture_blur, "Texture Blur", 1.0f);
+
+  SOCKET_IN_FLOAT(subsurface_ior, "IOR", 1.4f);
+  SOCKET_IN_FLOAT(subsurface_anisotropy, "Anisotropy", 0.0f);
 
   SOCKET_OUT_CLOSURE(BSSRDF, "BSSRDF");
 
@@ -3066,20 +3077,19 @@ NODE_DEFINE(SubsurfaceScatteringNode)
 
 SubsurfaceScatteringNode::SubsurfaceScatteringNode() : BsdfNode(get_node_type())
 {
-  closure = falloff;
+  closure = method;
 }
 
 void SubsurfaceScatteringNode::compile(SVMCompiler &compiler)
 {
-  closure = falloff;
-  BsdfNode::compile(
-      compiler, input("Scale"), input("Texture Blur"), input("Radius"), input("Sharpness"));
+  closure = method;
+  BsdfNode::compile(compiler, input("Scale"), input("IOR"), input("Radius"), input("Anisotropy"));
 }
 
 void SubsurfaceScatteringNode::compile(OSLCompiler &compiler)
 {
-  closure = falloff;
-  compiler.parameter(this, "falloff");
+  closure = method;
+  compiler.parameter(this, "method");
   compiler.add(this, "node_subsurface_scattering");
 }
 
@@ -3786,20 +3796,6 @@ void GeometryNode::compile(OSLCompiler &compiler)
   compiler.add(this, "node_geometry");
 }
 
-int GeometryNode::get_group()
-{
-  ShaderOutput *out;
-  int result = ShaderNode::get_group();
-
-  /* Backfacing uses NODE_LIGHT_PATH */
-  out = output("Backfacing");
-  if (!out->links.empty()) {
-    result = max(result, NODE_GROUP_LEVEL_1);
-  }
-
-  return result;
-}
-
 /* TextureCoordinate */
 
 NODE_DEFINE(TextureCoordinateNode)
@@ -5926,33 +5922,33 @@ NODE_DEFINE(OutputAOVNode)
 OutputAOVNode::OutputAOVNode() : ShaderNode(get_node_type())
 {
   special_type = SHADER_SPECIAL_TYPE_OUTPUT_AOV;
-  slot = -1;
+  offset = -1;
 }
 
 void OutputAOVNode::simplify_settings(Scene *scene)
 {
-  slot = scene->film->get_aov_offset(scene, name.string(), is_color);
-  if (slot == -1) {
-    slot = scene->film->get_aov_offset(scene, name.string(), is_color);
+  offset = scene->film->get_aov_offset(scene, name.string(), is_color);
+  if (offset == -1) {
+    offset = scene->film->get_aov_offset(scene, name.string(), is_color);
   }
 
-  if (slot == -1 || is_color) {
+  if (offset == -1 || is_color) {
     input("Value")->disconnect();
   }
-  if (slot == -1 || !is_color) {
+  if (offset == -1 || !is_color) {
     input("Color")->disconnect();
   }
 }
 
 void OutputAOVNode::compile(SVMCompiler &compiler)
 {
-  assert(slot >= 0);
+  assert(offset >= 0);
 
   if (is_color) {
-    compiler.add_node(NODE_AOV_COLOR, compiler.stack_assign(input("Color")), slot);
+    compiler.add_node(NODE_AOV_COLOR, compiler.stack_assign(input("Color")), offset);
   }
   else {
-    compiler.add_node(NODE_AOV_VALUE, compiler.stack_assign(input("Value")), slot);
+    compiler.add_node(NODE_AOV_VALUE, compiler.stack_assign(input("Value")), offset);
   }
 }