Graphcanvas on GS_Play Gameplay Framework

Descriptor & Topology

Mon, 01 Jan 0001 00:00:00 +0000

The GraphSystemDescriptor tells gs_graphcanvas what kind of editor to build. It is a plain struct that you fill out and pass to the MainWindow constructor.

GraphSystemDescriptor Fields

Identity

Field	Type	Description
`systemId`	`const char*`	Unique ID string (e.g., `"dialogue"`, `"audiograph"`, `"unitaction"`). Used for node filtering.
`systemName`	`const char*`	Display name shown in the editor title bar.
`fileExtension`	`const char*`	File extension for graph files (e.g., `".dialogue"`, `".audiograph"`).
`mimeType`	`const char*`	MIME type for drag-drop from the node palette.
`saveIdentifier`	`const char*`	QSettings key for persisting window layout state.
`editorId`	`GraphCanvas::EditorId`	Unique editor ID for the GraphCanvas system.

Topology

Field	Type	Default	Description
`topology`	`GraphTopology`	`FlowGraph`	Determines connection style, slot types, and execution model.

Topology options:

Nodes

Mon, 01 Jan 0001 00:00:00 +0000

All gs_graphcanvas nodes inherit from BaseNode, which extends GraphModel::Node. BaseNode provides slot registration helpers, flow slot support, inspector property reflection, and transition descriptor management for state machines.

Slot Registration

Slots are registered in the RegisterSlots() override using helper macros:

GS_INPUT_SLOT_TYPED("slot_name", "Display Name", DataTypeEnum, DefaultValue)
GS_OUTPUT_SLOT_TYPED("slot_name", "Display Name", DataTypeEnum)
GS_INPUT_SLOT_CONNECTION("slot_name", "Display Name") // Connection-only, no inline editor
GS_MULTI_INPUT_SLOT_CONNECTION("slot_name", "Display Name") // Multiple connections allowed

All input slots use editableOnNode=true by default, providing inline value editing directly on the node in the graph canvas.

Editor Window

Mon, 01 Jan 0001 00:00:00 +0000

The MainWindow class provides a complete graph editor out of the box. Downstream editors subclass it and override virtual hooks to add domain-specific behavior.

Out-of-the-Box Features

Every MainWindow instance includes:

Multi-document tabs — Each graph opens in its own tab with dirty tracking (asterisk * in tab title) and close-with-save prompts
File menu — New, Open, Save, Save As, Open Recent (tracks last 10 files)
Edit menu — Undo/Redo (Ctrl+Z / Ctrl+Y), Cut/Copy/Paste
Node palette — Searchable list of available nodes with drag-drop creation
Inspector panel — Auto-generated property editor from node EditContext reflection
Variable panel — Variable declarations, type selection, and default value editing (when enabled)

Virtual Hooks

MainWindow provides virtual methods for downstream customization:

Variables

Mon, 01 Jan 0001 00:00:00 +0000

When variablesEnabled = true in the GraphSystemDescriptor, the framework provides a complete variable system for storing and reading named values within a graph.

Variable Panel

The Variable Panel is a dock widget with a table listing all declared variables. Each variable has:

Name — User-defined identifier
Data Type — Selected from a dropdown of registered types (Bool, Int, Float, String, etc.)
Default Value — Type-specific editor (checkbox for Bool, spinner for numeric, text field for String, multi-field for vectors, color picker for Color)

Variables are per-graph. Add or remove variables using the panel controls. Undo/redo integration is automatic.

Execution Engines

Mon, 01 Jan 0001 00:00:00 +0000

gs_graphcanvas provides three execution engines — one for each topology. All share a common GraphExecutionContext for variable storage and value resolution, and GraphInstance for creating independent runtime copies.

FlowGraphEvaluator

Topology: FlowGraph

Step/wait/resume execution model for sequential graphs. The evaluator follows FlowIn/FlowOut connections from node to node.

Nodes implement the IExecutableNode interface:

FlowResult Execute(GraphExecutionContext& context);

FlowResult controls what happens after a node executes:

Result	Behavior
`Continue`	Immediately proceed to the next connected node
`Wait`	Pause execution until `Resume()` is called externally
`Stop`	End graph execution

Used by: Dialogue Editor — text nodes return Wait while dialogue is displayed, then Resume() advances to the next node.