Add repeat zone support

Author: carson-katri

api/static/repeat.py

@@ -0,0 +1,51 @@
+import bpy
+import inspect
+import typing
+
+def repeat_zone(block: typing.Callable):
+    """
+    Create a repeat input/output block.
+
+    > Only available in Blender 4.0+.
+    """
+    def wrapped(*args, **kwargs):
+        from geometry_script.api.node_mapper import OutputsList, set_or_create_link
+        from geometry_script.api.state import State
+        from geometry_script.api.types import Type, socket_class_to_data_type
+
+        signature = inspect.signature(block)
+        
+        # setup zone
+        repeat_in = State.current_node_tree.nodes.new(bpy.types.GeometryNodeRepeatInput.__name__)
+        repeat_out = State.current_node_tree.nodes.new(bpy.types.GeometryNodeRepeatOutput.__name__)
+        repeat_in.pair_with_output(repeat_out)
+
+        # clear state items
+        for item in repeat_out.repeat_items:
+            repeat_out.repeat_items.remove(item)
+
+        # link the iteration count
+        set_or_create_link(args[0], repeat_in.inputs[0])
+
+        # create state items from block signature
+        repeat_items = {}
+        for param in signature.parameters.values():
+            repeat_items[param.name] = (param.annotation, param.default, None, None)
+        for i, arg in enumerate(repeat_items.items()):
+            repeat_out.repeat_items.new(socket_class_to_data_type(arg[1][0].socket_type), arg[0].replace('_', ' ').title())
+            # skip the first index, which is reserved for the iteration count
+            i = i + 1
+            set_or_create_link(kwargs[arg[0]] if arg[0] in kwargs else args[i], repeat_in.inputs[i])
+        
+        step = block(*[Type(o) for o in repeat_in.outputs[:-1]])
+
+        if isinstance(step, Type):
+            step = (step,)
+        for i, result in enumerate(step):
+            set_or_create_link(result, repeat_out.inputs[i])
+
+        if len(repeat_out.outputs[:-1]) == 1:
+            return Type(repeat_out.outputs[0])
+        else:
+            return OutputsList({o.name.lower().replace(' ', '_'): Type(o) for o in repeat_out.outputs[:-1]})
+    return wrapped

api/static/simulation.py

@@ -6,6 +6,8 @@ def simulation_zone(block: typing.Callable):
     """
     Create a simulation input/output block.
 
+    In Blender 4.0+, you must return a boolean value for the "Skip" argument as the first element in the return tuple.
+
     > Only available in Blender 3.6+.
     """
     def wrapped(*args, **kwargs):
@@ -37,7 +39,7 @@ def wrapped(*args, **kwargs):
         if isinstance(step, Type):
             step = (step,)
         for i, result in enumerate(step):
-            State.current_node_tree.links.new(result._socket, simulation_out.inputs[i])
+            set_or_create_link(result, simulation_out.inputs[i])
 
         if len(simulation_out.outputs[:-1]) == 1:
             return Type(simulation_out.outputs[0])

api/tree.py

@@ -11,6 +11,7 @@
 from .static.curve import *
 from .static.expression import *
 from .static.input_group import *
+from .static.repeat import *
 from .static.sample_mode import *
 from .static.simulation import *
 from .arrange import _arrange

book/src/SUMMARY.md

@@ -23,7 +23,8 @@
     - [Boolean Math](./api/advanced-scripting/boolean-math.md)
     - [Curves](./api/advanced-scripting/curves.md)
     - [Drivers](./api/advanced-scripting/drivers.md)
-    - [Simulation](./api/advanced-scripting/simulation.md)
+    - [Simulation Zones](./api/advanced-scripting/simulation-zones.md)
+    - [Repeat Zones](./api/advanced-scripting/repeat-zones.md)
 
 # Tutorials
 

book/src/api/advanced-scripting/repeat-zones.md

@@ -0,0 +1,42 @@
+# Repeat Zones
+
+Blender 4.0 introduced repeat zones.
+
+Using a *Repeat Input* and *Repeat Output* node, you can loop a block of nodes for a specific number of iterations.
+
+You must use the `@repeat_zone` decorator to create these special linked nodes.
+
+```python
+from geometry_script import *
+
+@tree
+def test_loop(geometry: Geometry):
+    @repeat_zone
+    def doubler(value: Float):
+        return value * 2
+    return points(count=doubler(5, 1)) # double the input value 5 times.
+```
+
+The function should modify the input values and return them in the same order.
+
+When calling the repeat zone, pass the *Iterations* argument first, then any other arguments the function accepts.
+
+For example:
+
+```python
+def doubler(value: Float) -> Float
+```
+
+would be called as:
+
+```python
+doubler(iteration_count, value)
+```
+
+When a repeat zone has multiple arguments, return a tuple from the zone.
+
+```python
+@repeat_zone
+def multi_doubler(value1: Float, value2: Float):
+    return (value1 * 2, value2 * 2)
+```

book/src/api/advanced-scripting/simulation.md renamed to book/src/api/advanced-scripting/simulation-zones.md

@@ -1,4 +1,4 @@
-# Simulation
+# Simulation Zones
 
 Blender 3.6 includes simulation nodes.
 
@@ -19,4 +19,20 @@ def test_sim(geometry: Geometry):
 
 The first argument should always be `delta_time`. Any other arguments must also be returned as a tuple with their modified values.
 Each frame, the result from the previous frame is passed into the zone's inputs.
-The initial call to `my_sim` in `test_sim` provides the initial values for the simulation.
+The initial call to `my_sim` in `test_sim` provides the initial values for the simulation.
+
+## Blender 4.0+
+
+A "Skip" argument was added to the *Simulation Output* node in Blender 4.0.
+
+Return a boolean value first from any simulation zone to determine whether the step should be skipped.
+
+The simplest way to migrate existing node trees is by adding `False` to the return tuple.
+
+```python
+@simulation_zone
+def my_sim(delta_time, geometry: Geometry, value: Float):
+    return (False, geometry, value)
+```
+
+You can pass any boolean value as the skip output.