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, 35 insertions, 6 deletions

diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index e6fb9d86b0a..905316a937d 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -112,20 +112,26 @@ namespace blender {
 namespace nodes {
 class SocketMFNetworkBuilder;
 class NodeMFNetworkBuilder;
+class GeoNodeExecParams;
 }  // namespace nodes
 namespace fn {
+class CPPType;
 class MFDataType;
-}
+}  // namespace fn
 }  // namespace blender
 
 using NodeExpandInMFNetworkFunction = void (*)(blender::nodes::NodeMFNetworkBuilder &builder);
-using SocketGetMFDataTypeFunction = blender::fn::MFDataType (*)();
+using NodeGeometryExecFunction = void (*)(blender::nodes::GeoNodeExecParams params);
+using SocketGetCPPTypeFunction = const blender::fn::CPPType *(*)();
+using SocketGetCPPValueFunction = void (*)(const struct bNodeSocket &socket, void *r_value);
 using SocketExpandInMFNetworkFunction = void (*)(blender::nodes::SocketMFNetworkBuilder &builder);
 
 #else
 typedef void *NodeExpandInMFNetworkFunction;
-typedef void *SocketGetMFDataTypeFunction;
 typedef void *SocketExpandInMFNetworkFunction;
+typedef void *NodeGeometryExecFunction;
+typedef void *SocketGetCPPTypeFunction;
+typedef void *SocketGetCPPValueFunction;
 #endif
 
 /**
@@ -181,10 +187,12 @@ typedef struct bNodeSocketType {
   /* Callback to free the socket type. */
   void (*free_self)(struct bNodeSocketType *stype);
 
-  /* Returns the multi-function data type of this socket type. */
-  SocketGetMFDataTypeFunction get_mf_data_type;
   /* Expands the socket into a multi-function node that outputs the socket value. */
   SocketExpandInMFNetworkFunction expand_in_mf_network;
+  /* Return the CPPType of this socket. */
+  SocketGetCPPTypeFunction get_cpp_type;
+  /* Get the value of this socket in a generic way. */
+  SocketGetCPPValueFunction get_cpp_value;
 } bNodeSocketType;
 
 typedef void *(*NodeInitExecFunction)(struct bNodeExecContext *context,
@@ -302,6 +310,9 @@ typedef struct bNodeType {
   /* Expands the bNode into nodes in a multi-function network, which will be evaluated later on. */
   NodeExpandInMFNetworkFunction expand_in_mf_network;
 
+  /* Execute a geometry node. */
+  NodeGeometryExecFunction geometry_node_execute;
+
   /* RNA integration */
   ExtensionRNA rna_ext;
 } bNodeType;
@@ -438,7 +449,7 @@ bool ntreeHasType(const struct bNodeTree *ntree, int type);
 bool ntreeHasTree(const struct bNodeTree *ntree, const struct bNodeTree *lookup);
 void ntreeUpdateTree(struct Main *main, struct bNodeTree *ntree);
 void ntreeUpdateAllNew(struct Main *main);
-void ntreeUpdateAllUsers(struct Main *main, struct ID *ngroup);
+void ntreeUpdateAllUsers(struct Main *main, struct bNodeTree *ngroup);
 
 void ntreeGetDependencyList(struct bNodeTree *ntree, struct bNode ***deplist, int *totnodes);
 
@@ -1323,6 +1334,24 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 /** \} */
 
 /* -------------------------------------------------------------------- */
+/** \name Geometry Nodes
+ * \{ */
+
+#define GEO_NODE_TRIANGULATE 1000
+#define GEO_NODE_EDGE_SPLIT 1001
+#define GEO_NODE_TRANSFORM 1002
+#define GEO_NODE_BOOLEAN 1003
+#define GEO_NODE_POINT_DISTRIBUTE 1004
+#define GEO_NODE_POINT_INSTANCE 1005
+#define GEO_NODE_SUBDIVISION_SURFACE 1006
+#define GEO_NODE_OBJECT_INFO 1007
+#define GEO_NODE_RANDOM_ATTRIBUTE 1008
+#define GEO_NODE_ATTRIBUTE_MATH 1009
+#define GEO_NODE_JOIN_GEOMETRY 1010
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Function Nodes
  * \{ */