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Grid Building Docs

BuildingSystem

Summary

Section titled “Summary”

Manages placement of objects in the game world.

Handles preview, placement validation, and build actions. Uses tile collision indicators to show valid/invalid spots before placement. Checks all rules before adding objects to the world and emits signals for build success or failure.

Constants

Section titled “Constants”
const WARNING_INVALID_PLACEABLE = “Invalid placeable resource. Can’t instantiate. [%s]”

Tracks drag events for build button. InputEventScreenDrag instance used to track drag events for build actions. Updated as the user drags to new tiles during multi-build mode.

const WARNING_NO_PREVIEW = “No preview instance created to instantiate yet. Returning null.”

Properties

Section titled “Properties”
placement_polygons: Array[CollisionPolygon2D]

Drag build manager for multi-tile placement.

Instantiates building objects for placement.

Tracks tiles where placement has been attempted during current drag session

Collision polygons for placement indicators.

preview_layer: int

Preview layer index for buildable/unbuildable tiles.

selected_placeable: Placeable

Currently selected placeable resource.

indicators_group: Node2D

Parent node for collision indicators.

Methods

Section titled “Methods”
get_building_state( )

The report of the active ongoing placement

legacy accessors expected in some validator/integration tests

get_targeting_state( )
check_ready_to_build( ) -> bool

Returns true if system is ready to build. Checks if the system is ready to build by validating the selected placeable and build context. Returns true if all build requirements are met and no issues are found.

is_in_build_mode( ) -> bool

Returns true if the building system is currently in build mode. Checks the current mode state to determine if build mode is active.

exit_build_mode( ) -> void

Exits build mode and cleans up all build-related elements. Sets the mode to OFF, clears the preview, and tears down indicators.

resolve_gb_dependencies( p_container: GBCompositionContainer ) -> void
try_build( ) -> PlacementReport

Attempts to place a building at the current preview location if all placement rules pass. Validates all placement rules and emits success or failure signals based on the result. Returns the built Node2D if successful, null otherwise.

is_drag_building( ) -> bool

Determine whether or not the building system is currently drag building through the DragBuildManager

try_build_at_position( p_global_position: Vector2 ) -> Node2D

Legacy API compatibility method for tests Attempts to place a building at the specified position Temporarily moves the targeting system to the position, attempts placement, then restores position

enter_build_mode( p_placeable: Placeable ) -> PlacementReport

Sets up a preview instance for the selected placeable. Switches to build mode, clears previous preview, and creates a new preview instance. Returns true if setup is successful.

p_placeable: Placeable - Placeable resource to create preview for

clear_preview( )

Removes the current preview instance. Removes the current preview instance and resets placement manager state. Called when exiting build mode or clearing preview.

instance_preview( p_placeable: Placeable ) -> Node2D

Creates a preview instance with limited functionality. Strips scripts not needed for preview and replaces root node script if set in config. Used for visual feedback before placement.

p_placeable: Placeable - Placeable resource to create preview instance for

get_runtime_issues( ) -> Array[String]

Validates that all required dependencies are set. This is called automatically when entering build mode, but can also be called manually after scene loads to check if all dependencies are properly configured. Returns list of validation issues (empty if valid).

get_builder_owner( ) -> GBOwner

Get the current GBOwner of the building object which is the root node of the GBOwner in the active GBOwnerContext that is assigned to the BuildingState

start_drag( )

Starts drag-building mode. Initiates drag-building mode if enabled in settings. Sets up drag manager and starts tracking drag events.

stop_drag( )

Stops drag-building mode. Ends drag-building mode if enabled in settings. Stops drag manager and drag event tracking. Private helper to stop drag operation when multi-build is enabled.

report_built( p_report: PlacementReport ) -> void

Reports a successful build action through the BuildingState

report_failure( p_report: PlacementReport ) -> void

Reports a failed build action through the BuildingState

get_lazy_drag_manager( ) -> DragBuildManager

Private lazy getter for drag build manager. Creates and configures the manager if it doesn’t exist.

return: DragBuildManager - The drag build manager instance

Source

Section titled “Source”

addons/grid_building/systems/building/building_system.gd

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Generated on 2025-09-07