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

5 files changed, 48 insertions, 18 deletions

diff --git a/source/blender/makesdna/DNA_modifier_defaults.h b/source/blender/makesdna/DNA_modifier_defaults.h
index b5bcfa4d157..f73f43ddade 100644
--- a/source/blender/makesdna/DNA_modifier_defaults.h
+++ b/source/blender/makesdna/DNA_modifier_defaults.h
@@ -573,7 +573,7 @@
     .flag = 0, \
   }
 
-#define _DNA_DEFAULT_SimulationModifierData \
+#define _DNA_DEFAULT_NodesModifierData \
   { 0 }
 
 #define _DNA_DEFAULT_SkinModifierData \
diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 7b5bdac47f5..43ed532a65b 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -94,7 +94,7 @@ typedef enum ModifierType {
   eModifierType_WeightedNormal = 54,
   eModifierType_Weld = 55,
   eModifierType_Fluid = 56,
-  eModifierType_Simulation = 57,
+  eModifierType_Nodes = 57,
   eModifierType_MeshToVolume = 58,
   eModifierType_VolumeDisplace = 59,
   eModifierType_VolumeToMesh = 60,
@@ -2224,9 +2224,16 @@ enum {
 #define MOD_MESHSEQ_READ_ALL \
   (MOD_MESHSEQ_READ_VERT | MOD_MESHSEQ_READ_POLY | MOD_MESHSEQ_READ_UV | MOD_MESHSEQ_READ_COLOR)
 
-typedef struct SimulationModifierData {
+typedef struct NodesModifierSettings {
+  /* This stores data that is passed into the node group. */
+  struct IDProperty *properties;
+} NodesModifierSettings;
+
+typedef struct NodesModifierData {
   ModifierData modifier;
-} SimulationModifierData;
+  struct bNodeTree *node_group;
+  struct NodesModifierSettings settings;
+} NodesModifierData;
 
 typedef struct MeshToVolumeModifierData {
   ModifierData modifier;
diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index fdae3559599..29c83d2d4ed 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -504,7 +504,7 @@ typedef struct bNodeTree {
 #define NTREE_SHADER 0
 #define NTREE_COMPOSIT 1
 #define NTREE_TEXTURE 2
-#define NTREE_SIMULATION 3
+#define NTREE_GEOMETRY 3
 
 /* ntree->init, flag */
 #define NTREE_TYPE_INIT 1
@@ -1437,17 +1437,32 @@ typedef enum NodeShaderOutputTarget {
   SHD_OUTPUT_CYCLES = 2,
 } NodeShaderOutputTarget;
 
-/* Particle Time Step Event node */
-typedef enum NodeSimParticleTimeStepEventType {
-  NODE_PARTICLE_TIME_STEP_EVENT_BEGIN = 0,
-  NODE_PARTICLE_TIME_STEP_EVENT_END = 1,
-} NodeSimParticleTimeStepEventType;
-
-/* Simulation Time node */
-typedef enum NodeSimInputTimeType {
-  NODE_SIM_INPUT_SIMULATION_TIME = 0,
-  NODE_SIM_INPUT_SCENE_TIME = 1,
-} NodeSimInputTimeType;
+/* Geometry Nodes */
+
+/* Boolean Node */
+typedef enum GeometryNodeBooleanOperation {
+  GEO_NODE_BOOLEAN_INTERSECT = 0,
+  GEO_NODE_BOOLEAN_UNION = 1,
+  GEO_NODE_BOOLEAN_DIFFERENCE = 2,
+} GeometryNodeBooleanOperation;
+
+/* Triangulate Node */
+typedef enum GeometryNodeTriangulateNGons {
+  GEO_NODE_TRIANGULATE_NGON_BEAUTY = 0,
+  GEO_NODE_TRIANGULATE_NGON_EARCLIP = 1,
+} GeometryNodeTriangulateNGons;
+
+typedef enum GeometryNodeTriangulateQuads {
+  GEO_NODE_TRIANGULATE_QUAD_BEAUTY = 0,
+  GEO_NODE_TRIANGULATE_QUAD_FIXED = 1,
+  GEO_NODE_TRIANGULATE_QUAD_ALTERNATE = 2,
+  GEO_NODE_TRIANGULATE_QUAD_SHORTEDGE = 3,
+} GeometryNodeTriangulateQuads;
+
+typedef enum GeometryNodeUseAttributeFlag {
+  GEO_NODE_USE_ATTRIBUTE_A = (1 << 0),
+  GEO_NODE_USE_ATTRIBUTE_B = (1 << 1),
+} GeometryNodeUseAttributeFlag;
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 5a00b6479d5..328e4d2ba22 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -51,6 +51,7 @@ struct RigidBodyOb;
 struct SculptSession;
 struct SoftBody;
 struct bGPdata;
+struct GeometrySet;
 
 /* Vertex Groups - Name Info */
 typedef struct bDeformGroup {
@@ -153,6 +154,13 @@ typedef struct Object_Runtime {
    * It has all modifiers applied.
    */
   struct ID *data_eval;
+
+  /**
+   * Some objects support evaluating to a geometry set instead of a single ID. In those cases the
+   * evaluated geometry will be stored here instead of in #data_eval.
+   */
+  struct GeometrySet *geometry_set_eval;
+
   /**
    * Mesh structure created during object evaluation.
    * It has deformation only modifiers applied on it.
diff --git a/source/blender/makesdna/intern/dna_defaults.c b/source/blender/makesdna/intern/dna_defaults.c
index 8c95a6d2a31..1a8bd25215f 100644
--- a/source/blender/makesdna/intern/dna_defaults.c
+++ b/source/blender/makesdna/intern/dna_defaults.c
@@ -271,7 +271,7 @@ SDNA_DEFAULT_DECL_STRUCT(ScrewModifierData);
 /* Shape key modifier has no items. */
 SDNA_DEFAULT_DECL_STRUCT(ShrinkwrapModifierData);
 SDNA_DEFAULT_DECL_STRUCT(SimpleDeformModifierData);
-SDNA_DEFAULT_DECL_STRUCT(SimulationModifierData);
+SDNA_DEFAULT_DECL_STRUCT(NodesModifierData);
 SDNA_DEFAULT_DECL_STRUCT(SkinModifierData);
 SDNA_DEFAULT_DECL_STRUCT(SmoothModifierData);
 /* Softbody modifier skipped for now. */
@@ -491,7 +491,7 @@ const void *DNA_default_table[SDNA_TYPE_MAX] = {
     /* Shape key modifier has no items. */
     SDNA_DEFAULT_DECL(ShrinkwrapModifierData),
     SDNA_DEFAULT_DECL(SimpleDeformModifierData),
-    SDNA_DEFAULT_DECL(SimulationModifierData),
+    SDNA_DEFAULT_DECL(NodesModifierData),
     SDNA_DEFAULT_DECL(SkinModifierData),
     SDNA_DEFAULT_DECL(SmoothModifierData),
     /* Softbody modifier skipped for now. */