Geometry Nodes: initial scattering and geometry nodes

This is the initial merge from the geometry-nodes branch.
Nodes:
* Attribute Math
* Boolean
* Edge Split
* Float Compare
* Object Info
* Point Distribute
* Point Instance
* Random Attribute
* Random Float
* Subdivision Surface
* Transform
* Triangulate

It includes the initial evaluation of geometry node groups in the Geometry Nodes modifier.

Notes on the Generic attribute access API

The API adds an indirection for attribute access. That has the following benefits:
* Most code does not have to care about how an attribute is stored internally.
  This is mainly necessary, because we have to deal with "legacy" attributes
  such as vertex weights and attributes that are embedded into other structs
  such as vertex positions.
* When reading from an attribute, we generally don't care what domain the
  attribute is stored on. So we want to abstract away the interpolation that
  that adapts attributes from one domain to another domain (this is not
  actually implemented yet).

Other possible improvements for later iterations include:
* Actually implement interpolation between domains.
* Don't use inheritance for the different attribute types. A single class for read
  access and one for write access might be enough, because we know all the ways
  in which attributes are stored internally. We don't want more different internal
  structures in the future. On the contrary, ideally we can consolidate the different
  storage formats in the future to reduce the need for this indirection.
* Remove the need for heap allocations when creating attribute accessors.

It includes commits from:
* Dalai Felinto
* Hans Goudey
* Jacques Lucke
* Léo Depoix

1 files changed, 66 insertions, 12 deletions

diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index c0f3197b2d1..09c1869b84b 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -29,7 +29,6 @@
 #include "DNA_object_force_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
-#include "DNA_simulation_types.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -43,6 +42,7 @@
 #include "BKE_dynamicpaint.h"
 #include "BKE_effect.h"
 #include "BKE_fluid.h" /* For BKE_fluid_modifier_free & BKE_fluid_modifier_create_type_data */
+#include "BKE_idprop.h"
 #include "BKE_mesh_mapping.h"
 #include "BKE_mesh_remap.h"
 #include "BKE_multires.h"
@@ -57,6 +57,8 @@
 #include "WM_api.h"
 #include "WM_types.h"
 
+#include "MOD_nodes.h"
+
 const EnumPropertyItem rna_enum_object_modifier_type_items[] = {
     {0, "", 0, N_("Modify"), ""},
     {eModifierType_DataTransfer,
@@ -141,6 +143,7 @@ const EnumPropertyItem rna_enum_object_modifier_type_items[] = {
      ICON_MOD_EDGESPLIT,
      "Edge Split",
      "Split away joined faces at the edges"},
+    {eModifierType_Nodes, "NODES", ICON_NODETREE, "Geometry Nodes", ""},
     {eModifierType_Mask,
      "MASK",
      ICON_MOD_MASK,
@@ -305,11 +308,6 @@ const EnumPropertyItem rna_enum_object_modifier_type_items[] = {
      "Spawn particles from the shape"},
     {eModifierType_Softbody, "SOFT_BODY", ICON_MOD_SOFT, "Soft Body", ""},
     {eModifierType_Surface, "SURFACE", ICON_MODIFIER, "Surface", ""},
-    {eModifierType_Simulation,
-     "SIMULATION",
-     ICON_PHYSICS,
-     "Simulation",
-     ""}, /* TODO: Use correct icon. */
     {0, NULL, 0, NULL, NULL},
 };
 
@@ -1588,6 +1586,37 @@ static int rna_MeshSequenceCacheModifier_read_velocity_get(PointerRNA *ptr)
 #  endif
 }
 
+static bool rna_NodesModifier_node_group_poll(PointerRNA *ptr, PointerRNA value)
+{
+  NodesModifierData *nmd = ptr->data;
+  bNodeTree *ntree = value.data;
+  UNUSED_VARS(nmd, ntree);
+  return true;
+}
+
+static void rna_NodesModifier_node_group_update(Main *bmain, Scene *scene, PointerRNA *ptr)
+{
+  Object *object = (Object *)ptr->owner_id;
+  NodesModifierData *nmd = ptr->data;
+  rna_Modifier_dependency_update(bmain, scene, ptr);
+  MOD_nodes_update_interface(object, nmd);
+}
+
+static IDProperty *rna_NodesModifierSettings_properties(PointerRNA *ptr, bool create)
+{
+  NodesModifierSettings *settings = ptr->data;
+  if (create && settings->properties == NULL) {
+    IDPropertyTemplate val = {0};
+    settings->properties = IDP_New(IDP_GROUP, &val, "Nodes Modifier Settings");
+  }
+  return settings->properties;
+}
+
+static char *rna_NodesModifierSettings_path(PointerRNA *UNUSED(ptr))
+{
+  return BLI_strdup("settings");
+}
+
 #else
 
 static void rna_def_property_subdivision_common(StructRNA *srna)
@@ -6907,18 +6936,43 @@ static void rna_def_modifier_weightednormal(BlenderRNA *brna)
 }
 
 #  ifdef WITH_GEOMETRY_NODES
-static void rna_def_modifier_simulation(BlenderRNA *brna)
+static void rna_def_modifier_nodes_settings(BlenderRNA *brna)
 {
   StructRNA *srna;
 
-  srna = RNA_def_struct(brna, "SimulationModifier", "Modifier");
-  RNA_def_struct_ui_text(srna, "Simulation Modifier", "");
-  RNA_def_struct_sdna(srna, "SimulationModifierData");
-  RNA_def_struct_ui_icon(srna, ICON_PHYSICS); /* TODO: Use correct icon. */
+  srna = RNA_def_struct(brna, "NodesModifierSettings", NULL);
+  RNA_def_struct_nested(brna, srna, "NodesModifier");
+  RNA_def_struct_path_func(srna, "rna_NodesModifierSettings_path");
+  RNA_def_struct_ui_text(
+      srna, "Nodes Modifier Settings", "Settings that are passed into the node group");
+  RNA_def_struct_idprops_func(srna, "rna_NodesModifierSettings_properties");
+}
+
+static void rna_def_modifier_nodes(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  srna = RNA_def_struct(brna, "NodesModifier", "Modifier");
+  RNA_def_struct_ui_text(srna, "Nodes Modifier", "");
+  RNA_def_struct_sdna(srna, "NodesModifierData");
+  RNA_def_struct_ui_icon(srna, ICON_MESH_DATA); /* TODO: Use correct icon. */
 
   RNA_define_lib_overridable(true);
 
+  prop = RNA_def_property(srna, "node_group", PROP_POINTER, PROP_NONE);
+  RNA_def_property_ui_text(prop, "Node Group", "Node group that controls what this modifier does");
+  RNA_def_property_pointer_funcs(prop, NULL, NULL, NULL, "rna_NodesModifier_node_group_poll");
+  RNA_def_property_flag(prop, PROP_EDITABLE);
+  RNA_def_property_update(prop, 0, "rna_NodesModifier_node_group_update");
+
+  prop = RNA_def_property(srna, "settings", PROP_POINTER, PROP_NONE);
+  RNA_def_property_flag(prop, PROP_NEVER_NULL);
+  RNA_def_property_ui_text(prop, "Settings", "Settings that are passed into the node group");
+
   RNA_define_lib_overridable(false);
+
+  rna_def_modifier_nodes_settings(brna);
 }
 #  endif
 
@@ -7277,7 +7331,7 @@ void RNA_def_modifier(BlenderRNA *brna)
   rna_def_modifier_surfacedeform(brna);
   rna_def_modifier_weightednormal(brna);
 #  ifdef WITH_GEOMETRY_NODES
-  rna_def_modifier_simulation(brna);
+  rna_def_modifier_nodes(brna);
 #  endif
   rna_def_modifier_mesh_to_volume(brna);
   rna_def_modifier_volume_displace(brna);