Simulations: Embed simulation node tree in simulation data block

This adds an embedded node tree to the simulation data block dna.
The UI in the `Simulation Editor` has been updated to show a list
of simulation data blocks, instead of individual node trees.

The new `SpaceNodeEditor.simulation` property wraps the existing
`SpaceNodeEditor.id` property. It allows scripts to get and set
the simulation data block that is being edited.

Reviewers: brecht, mont29

Differential Revision: https://developer.blender.org/D7301

release/scripts/startup/bl_operators/__init__.py

@@ -42,6 +42,7 @@ _modules = [
     "rigidbody",
     "screen_play_rendered_anim",
     "sequencer",
+    "simulation",
     "userpref",
     "uvcalc_follow_active",
     "uvcalc_lightmap",

release/scripts/startup/bl_operators/simulation.py

@@ -0,0 +1,39 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+import bpy
+
+class NewSimulation(bpy.types.Operator):
+    """Create a new simulation data block and edit it in the opened simulation editor"""
+
+    bl_idname = "simulation.new"
+    bl_label = "New Simulation"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    @classmethod
+    def poll(cls, context):
+        return context.area.type == 'NODE_EDITOR' and context.space_data.tree_type == 'SimulationNodeTree'
+
+    def execute(self, context):
+        simulation = bpy.data.simulations.new("Simulation")
+        context.space_data.simulation = simulation
+        return {'FINISHED'}
+
+classes = (
+    NewSimulation,
+)

release/scripts/startup/bl_ui/space_node.py

@@ -151,6 +151,14 @@ class NODE_HT_header(Header):
             if snode_id:
                 layout.prop(snode_id, "use_nodes")
 
+        elif snode.tree_type == 'SimulationNodeTree':
+            row = layout.row(align=True)
+            row.prop(snode, "simulation", text="")
+            row.operator("simulation.new", text="", icon='ADD')
+            simulation = snode.simulation
+            if simulation:
+                row.prop(snode.simulation, "use_fake_user", text="")
+
         else:
             # Custom node tree is edited as independent ID block
             NODE_MT_editor_menus.draw_collapsible(context, layout)

release/scripts/startup/nodeitems_builtins.py

@@ -58,6 +58,13 @@ class TextureNodeCategory(SortedNodeCategory):
                 context.space_data.tree_type == 'TextureNodeTree')
 
 
+class SimulationNodeCategory(SortedNodeCategory):
+    @classmethod
+    def poll(cls, context):
+        return (context.space_data.type == 'NODE_EDITOR' and
+                context.space_data.tree_type == 'SimulationNodeTree')
+
+
 # menu entry for node group tools
 def group_tools_draw(self, layout, context):
     layout.operator("node.group_make")
@@ -70,6 +77,7 @@ node_tree_group_type = {
     'CompositorNodeTree': 'CompositorNodeGroup',
     'ShaderNodeTree': 'ShaderNodeGroup',
     'TextureNodeTree': 'TextureNodeGroup',
+    'SimulationNodeTree': 'SimulationNodeGroup',
 }
 
 
@@ -467,17 +475,28 @@ texture_node_categories = [
     ]),
 ]
 
+simulation_node_categories = [
+    # Simulation Nodes
+    SimulationNodeCategory("SIM_GROUP", "Group", items=node_group_items),
+    SimulationNodeCategory("SIM_LAYOUT", "Layout", items=[
+        NodeItem("NodeFrame"),
+        NodeItem("NodeReroute"),
+    ]),
+]
+
 
 def register():
     nodeitems_utils.register_node_categories('SHADER', shader_node_categories)
     nodeitems_utils.register_node_categories('COMPOSITING', compositor_node_categories)
     nodeitems_utils.register_node_categories('TEXTURE', texture_node_categories)
+    nodeitems_utils.register_node_categories('SIMULATION', simulation_node_categories)
 
 
 def unregister():
     nodeitems_utils.unregister_node_categories('SHADER')
     nodeitems_utils.unregister_node_categories('COMPOSITING')
     nodeitems_utils.unregister_node_categories('TEXTURE')
+    nodeitems_utils.unregister_node_categories('SIMULATION')
 
 
 if __name__ == "__main__":