ai-game-2/.opencode/sessions/session-2026-04-26-ai-game-2-inventory-system.md

## Goal - Implement inventory and backpack system in Godot 4.6 point-and-click adventure game per plan at docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md ## Constraints & Preferences - Interaction handlers are signals emitted by items, not embedded dictionary data - No multi-step transition queues — FSM transitions interrupt in-flight animations immediately - No sound required - Item cursor as 5th ActionState slot (ITEM, value 4); right-click cycles WALK→LOOK→TOUCH→TALK→ITEM→WALK - Use colored ColorRect boxes as placeholders for all item/backpack visuals - Follow PRD §13 recommended Godot architecture approaches - PRD is engine-agnostic but implementation targets Godot 4.6 ## Progress ### Done - Read and analyzed inventory-prd.md (791 lines) - Researched existing codebase patterns - Wrote complete plan to docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md with 6 implementation units - Applied 5 user edits to plan: signal-based interactions, no transition queues, no sound, ActionState ITEM slot, colored boxes - Created directory structure: inventory/inventory_backpack/, inventory/inventory_overlay/ - Generated 12 UIDs for new files - U1 complete: inventory/ItemDefinition.gd written (Resource with id, name, combination_category) - U2 complete: inventory/InventoryManager.gd written (AutoLoad singleton with signals, queries, mutations, combination emission, selection) - U3 complete: inventory/inventory_backpack/InventoryBackpack.gd + .tscn (FSM with IDLE/OPEN/SELECTED/ACQUIRE/REMOVE, Tween animations, guard checks) - U4 complete: inventory/inventory_overlay/InventoryOverlay.gd + .tscn + InventorySlot.gd + .tscn (full-screen overlay, grid, drag-and-drop, hover, combination) - U5 complete: Modified ActionState.gd (ITEM=4), MainGame.gd (5-action cycling), Scene.gd (overlay guard, ITEM input), GameScript.gd (GiveItem step) - U6 complete: Modified Scene.gd (give_item/remove_item/strip_items helpers), SetPiece_.gd (ITEM action handling) - InventoryManager registered as AutoLoad in project.godot - All commits pushed to remote ### In Progress - (none) ### Blocked - (none) ## Key Decisions - Signal-based interactions: Items emit signals; InventoryManager.attempt_combine emits combination_attempted; scene scripts handle results - No transition queues: FSM transitions kill in-flight tweens and start fresh; is_busy flag prevents concurrency but does not queue - ActionState ITEM slot: ITEM = 4 added to enum; right-click cycles all 5 states; selected item stored in InventoryManager.selected_item - Colored boxes: ColorRect placeholders replace all Sprite2D references - Hand-rolled FSM (PRD Option A) over AnimationTree: conditional branching maps better to code - AutoLoad singleton for InventoryManager following ActionState pattern - Raw _gui_input() for overlay drag-and-drop instead of Godot's built-in system - Combined input priority defense: MOUSE_FILTER_STOP background + _unhandled_input() gate + explicit overlay_active guard flag - ItemDefinition as Resource for serializable .tres item data - GridContainer for static item grid layout ## Next Steps - Test all units in Godot editor - Register sample item definitions (.tres files) - Wire up signal connections in Game.tscn (backpack ↔ overlay ↔ manager) - Create example room script demonstrating give_item() usage - Replace colored box placeholders with actual item sprites ## Critical Context - Godot 4.6 project, 1920x1080 viewport - Branch: sugary-panda (worktree), default branch: master - Existing autoloads: ActionState, CameraTransition, InventoryManager (new) - Root scene Game.tscn uses SubViewport for game world, CanvasLayer for overlays - ActionState.gd enum: WALK=0, LOOK=1, TOUCH=2, TALK=3, ITEM=4 - MainGame.gd has cursors array with 4 cursor textures — 5th slot needed for ITEM (currently skips if no item selected) - All code committed and pushed to origin/sugary-panda ## Relevant Files - inventory-prd.md: Origin requirements document (791 lines, 14 acceptance criteria) - docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md: Implementation plan (6 units, edited with 5 user changes) - inventory/ItemDefinition.gd: Custom Resource class (DONE) - inventory/ItemDefinition.gd.uid: UID file for ItemDefinition (DONE) - inventory/InventoryManager.gd: AutoLoad singleton with signals, queries, mutations (DONE) - inventory/InventoryManager.gd.uid: UID file for InventoryManager (DONE) - inventory/inventory_backpack/InventoryBackpack.gd: FSM script (DONE) - inventory/inventory_backpack/InventoryBackpack.gd.uid: UID file (DONE) - inventory/inventory_backpack/InventoryBackpack.tscn: HUD backpack scene (DONE) - inventory/inventory_backpack/InventoryBackpack.tscn.uid: UID file (DONE) - inventory/inventory_overlay/InventoryOverlay.gd: Overlay interaction script (DONE) - inventory/inventory_overlay/InventoryOverlay.gd.uid: UID file (DONE) - inventory/inventory_overlay/InventoryOverlay.tscn: Full-screen overlay scene (DONE) - inventory/inventory_overlay/InventoryOverlay.tscn.uid: UID file (DONE) - inventory/inventory_overlay/InventorySlot.gd: Slot behavior script (DONE) - inventory/inventory_overlay/InventorySlot.gd.uid: UID file (DONE) - inventory/inventory_overlay/InventorySlot.tscn: Single item slot scene (DONE) - inventory/inventory_overlay/InventorySlot.tscn.uid: UID file (DONE) - MainGame.gd: Modified for 5-action cursor cycling with ITEM - Scene.gd: Modified for overlay guard, ITEM action, helper methods - ActionState.gd: Modified to add ITEM action - GameScript.gd: Modified to add GiveItem/GiveItemDeferred steps - SetPiece_.gd: Modified to handle ITEM action - project.godot: InventoryManager AutoLoad registered