Merge node: add execution mode and output for input index

Sources/armory/logicnode/MergeNode.hx

@@ -2,11 +2,31 @@ package armory.logicnode;
 
 class MergeNode extends LogicNode {
 
+	/** Execution mode. **/
+	public var property0: String;
+
+	var lastInputIndex = -1;
+
 	public function new(tree: LogicTree) {
 		super(tree);
+		tree.notifyOnLateUpdate(lateUpdate);
 	}
 
 	override function run(from: Int) {
+		// Check if there already were executions on the same frame
+		if (lastInputIndex != -1 && property0 == "once_per_frame") {
+			return;
+		}
+
+		lastInputIndex = from;
 		runOutput(0);
 	}
+
+	override function get(from: Int): Dynamic {
+		return lastInputIndex;
+	}
+
+	function lateUpdate() {
+		lastInputIndex = -1;
+	}
 }

blender/arm/logicnode/logic/LN_merge.py

@@ -1,7 +1,23 @@
 from arm.logicnode.arm_nodes import *
 
+
 class MergeNode(ArmLogicTreeNode):
-    """Activates the output when any connected input is activated.
+    """Activates the output when at least one connected input is activated.
+    If multiple inputs are active, the behaviour is specified by the
+    `Execution Mode` option.
+
+    @output Active Input Index: [*Available if Execution Mode is set to
+        Once Per Input*] The index of the last input that activated the output,
+        -1 if there was no execution yet on the current frame.
+
+    @option Execution Mode: The node's behaviour if multiple inputs are
+        active on the same frame.
+
+        - `Once Per Input`: If multiple inputs are active on one frame, activate
+            the output for each active input individually (simple forwarding).
+
+        - `Once Per Frame`: If multiple inputs are active on one frame,
+            trigger the output only once.
 
     @option New: Add a new input socket.
     @option X Button: Remove the lowermost input socket."""
@@ -10,6 +26,21 @@ class MergeNode(ArmLogicTreeNode):
     arm_section = 'flow'
     arm_version = 1
 
+    def update_exec_mode(self, context):
+        self.outputs['Active Input Index'].hide = self.property0 == 'once_per_frame'
+
+    property0: EnumProperty(
+        name='Execution Mode',
+        description='The node\'s behaviour if multiple inputs are active on the same frame',
+        items=[('once_per_input', 'Once Per Input',
+                'If multiple inputs are active on one frame, activate the'
+                ' output for each active input individually (simple forwarding)'),
+               ('once_per_frame', 'Once Per Frame',
+                'If multiple inputs are active on one frame, trigger the output only once')],
+        default='once_per_input',
+        update=update_exec_mode,
+    )
+
     def __init__(self):
         super(MergeNode, self).__init__()
         array_nodes[str(id(self))] = self
@@ -17,10 +48,12 @@ class MergeNode(ArmLogicTreeNode):
     def init(self, context):
         super(MergeNode, self).init(context)
         self.add_output('ArmNodeSocketAction', 'Out')
+        self.add_output('NodeSocketInt', 'Active Input Index')
 
     def draw_buttons(self, context, layout):
-        row = layout.row(align=True)
+        layout.prop(self, 'property0', text='')
 
+        row = layout.row(align=True)
         op = row.operator('arm.node_add_input', text='New', icon='PLUS', emboss=True)
         op.node_index = str(id(self))
         op.socket_type = 'ArmNodeSocketAction'