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, 60 insertions, 5 deletions

diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index a0e03490fa3..8fdc86f8599 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -71,8 +71,8 @@
 #include "IMB_imbuf_types.h"
 
 #include "NOD_composite.h"
+#include "NOD_geometry.h"
 #include "NOD_shader.h"
-#include "NOD_simulation.h"
 #include "NOD_texture.h"
 #include "node_intern.h" /* own include */
 
@@ -3142,10 +3142,65 @@ static void node_texture_set_butfunc(bNodeType *ntype)
   }
 }
 
-/* ****************** BUTTON CALLBACKS FOR SIMULATION NODES ***************** */
+/* ****************** BUTTON CALLBACKS FOR GEOMETRY NODES ***************** */
 
-static void node_simulation_set_butfunc(bNodeType *UNUSED(ntype))
+static void node_geometry_buts_boolean_math(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
 {
+  uiItemR(layout, ptr, "operation", DEFAULT_FLAGS, "", ICON_NONE);
+}
+
+static void node_geometry_buts_subdivision_surface(uiLayout *layout,
+                                                   bContext *UNUSED(C),
+                                                   PointerRNA *UNUSED(ptr))
+{
+#ifndef WITH_OPENSUBDIV
+  uiItemL(layout, IFACE_("Disabled, built without OpenSubdiv"), ICON_ERROR);
+#else
+  UNUSED_VARS(layout);
+#endif
+}
+
+static void node_geometry_buts_triangulate(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
+{
+  uiItemR(layout, ptr, "quad_method", DEFAULT_FLAGS, "", ICON_NONE);
+  uiItemR(layout, ptr, "ngon_method", DEFAULT_FLAGS, "", ICON_NONE);
+}
+
+static void node_geometry_buts_random_attribute(uiLayout *layout,
+                                                bContext *UNUSED(C),
+                                                PointerRNA *ptr)
+{
+  uiItemR(layout, ptr, "data_type", DEFAULT_FLAGS, "", ICON_NONE);
+}
+
+static void node_geometry_buts_attribute_math(uiLayout *layout,
+                                              bContext *UNUSED(C),
+                                              PointerRNA *ptr)
+{
+  uiItemR(layout, ptr, "operation", DEFAULT_FLAGS, "", ICON_NONE);
+  uiItemR(layout, ptr, "input_type_a", DEFAULT_FLAGS, IFACE_("Type A"), ICON_NONE);
+  uiItemR(layout, ptr, "input_type_b", DEFAULT_FLAGS, IFACE_("Type B"), ICON_NONE);
+}
+
+static void node_geometry_set_butfunc(bNodeType *ntype)
+{
+  switch (ntype->type) {
+    case GEO_NODE_BOOLEAN:
+      ntype->draw_buttons = node_geometry_buts_boolean_math;
+      break;
+    case GEO_NODE_SUBDIVISION_SURFACE:
+      ntype->draw_buttons = node_geometry_buts_subdivision_surface;
+      break;
+    case GEO_NODE_TRIANGULATE:
+      ntype->draw_buttons = node_geometry_buts_triangulate;
+      break;
+    case GEO_NODE_RANDOM_ATTRIBUTE:
+      ntype->draw_buttons = node_geometry_buts_random_attribute;
+      break;
+    case GEO_NODE_ATTRIBUTE_MATH:
+      ntype->draw_buttons = node_geometry_buts_attribute_math;
+      break;
+  }
 }
 
 /* ****************** BUTTON CALLBACKS FOR FUNCTION NODES ***************** */
@@ -3290,7 +3345,7 @@ void ED_node_init_butfuncs(void)
     node_composit_set_butfunc(ntype);
     node_shader_set_butfunc(ntype);
     node_texture_set_butfunc(ntype);
-    node_simulation_set_butfunc(ntype);
+    node_geometry_set_butfunc(ntype);
     node_function_set_butfunc(ntype);
 
     /* define update callbacks for socket properties */
@@ -3302,7 +3357,7 @@ void ED_node_init_butfuncs(void)
   ntreeType_Composite->ui_icon = ICON_NODE_COMPOSITING;
   ntreeType_Shader->ui_icon = ICON_NODE_MATERIAL;
   ntreeType_Texture->ui_icon = ICON_NODE_TEXTURE;
-  ntreeType_Simulation->ui_icon = ICON_PHYSICS; /* TODO: Use correct icon. */
+  ntreeType_Geometry->ui_icon = ICON_PHYSICS; /* TODO: Use correct icon. */
 }
 
 void ED_init_custom_node_type(bNodeType *ntype)