@masatomakino/threejs-interactive-object
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    Class ButtonInteractionHandler<Value>

    Core interaction handler for pointer-interactive Three.js objects with button-like behavior.

    ButtonInteractionHandler provides comprehensive interaction management for Three.js display objects, handling pointer events, state transitions, material updates, and hover event duplicate management. This class was designed as a separate handler rather than extending display objects directly due to EventEmitter3's type system limitations that prevent proper event type extension in inheritance chains.

    The handler manages four primary interaction states (see state property for details).

    Hover Event Duplicate Management: Each handler instance manages its own over/out event duplicate suppression using asymmetric processing - over events are filtered for duplicates while out events are processed unconditionally for fail-safe cleanup.

    Note: When the handler is inactive (disabled or frozen), "out" events still perform internal cleanup (e.g., clearing hover/press sets) but are not emitted.

    Multi-touch Click Suppression: When multiple pointers interact with the same object, only the first pointer to complete a down-up sequence triggers a click event. Subsequent pointer releases are automatically suppressed to match native browser behavior where multi-touch gestures prevent synthetic click events.

    click - Emitted when a complete click interaction occurs (down followed by up). In multi-touch scenarios, only the first completing pointer triggers this event.

    down - Emitted when pointer is pressed down on the object

    up - Emitted when pointer is released after being pressed

    over - Emitted when pointer enters the object area

    out - Emitted when pointer leaves the object area

    import { ButtonInteractionHandler, StateMaterialSet } from '@masatomakino/threejs-interactive-object';
    import { BoxGeometry, Mesh, MeshBasicMaterial } from 'three';

    // Create materials for different states
    const materials = new StateMaterialSet({
      normal: new MeshBasicMaterial({ color: 0x0000ff }),
      over: new MeshBasicMaterial({ color: 0x00ff00 }),
      down: new MeshBasicMaterial({ color: 0xff0000 })
    });

    // Create interactive mesh
    const mesh = new Mesh(new BoxGeometry(1, 1, 1));
    const handler = new ButtonInteractionHandler({
      view: mesh,
      material: materials
    });

    // Associate custom data
    handler.value = { id: 'button1', action: 'save' };

    // Listen for events
    handler.on('click', (event) => {
      console.log('Button clicked:', handler.value);
    });

    Type Parameters

    • Value

      Type of arbitrary data associated with this interactive object. Used for identifying specific buttons in multi-button scenarios.

    Hierarchy (View Summary)

    Index

    Constructors

    constructor

    Properties

    _alpha _enable _materialSet? hoverPointerIds interactionScannable pressPointerIds state value view prefixed

    Accessors

    alpha enabled frozen isOver isPress materialSet mouseEnabled

    Methods

    addListener calculateCurrentState checkActivity disable emit enable eventNames listenerCount listeners off on once onMouseClick onMouseDownHandler onMouseOutHandler onMouseOverHandler onMouseUpHandler removeAllListeners removeListener switchEnable updateMaterial updateState

    Constructors

    • Creates a new ButtonInteractionHandler instance.

      Type Parameters

      • Value

      Parameters

      Returns ButtonInteractionHandler<Value>

      Initializes the interaction handler with the specified display object and optional material set. The handler immediately applies the initial material state upon creation.

      This constructor is typically not called directly by end users. Instead, it is invoked internally by display object constructors (ClickableMesh, ClickableSprite) or conversion utility functions (convertToClickableMesh, convertToClickableSprite).

      // Example 1: Creating clickable object from geometry and materials using ClickableMesh constructor
      import { ClickableMesh, StateMaterialSet } from '@masatomakino/threejs-interactive-object';
      import { BoxGeometry, MeshBasicMaterial } from 'three';

      const materials = new StateMaterialSet({
        normal: new MeshBasicMaterial({ color: 0x0000ff }),
        over: new MeshBasicMaterial({ color: 0x00ff00 }),
        down: new MeshBasicMaterial({ color: 0xff0000 })
      });

      const clickableMesh = new ClickableMesh({
        geo: new BoxGeometry(1, 1, 1),
        material: materials
      });

      clickableMesh.interactionHandler.value = { id: 'button1', action: 'save' };

      // Example 2: Converting existing Mesh to clickable using convertToClickableMesh
      import { convertToClickableMesh } from '@masatomakino/threejs-interactive-object';
      import { Mesh } from 'three';

      const existingMesh = new Mesh(new BoxGeometry(1, 1, 1), new MeshBasicMaterial());
      const convertedClickable = convertToClickableMesh<string>(existingMesh);
      convertedClickable.interactionHandler.value = 'converted-button';

      // Listen for click events
      convertedClickable.interactionHandler.on('click', (event) => {
        console.log('Button clicked:', convertedClickable.interactionHandler.value);
      });

      For most use cases, prefer using ClickableMesh/ClickableSprite constructors for new objects or convertToClickable* utility functions for existing objects, rather than instantiating ButtonInteractionHandler directly.

    Properties

    Protected Internal_alpha

    _alpha: number = 1.0

    Internal alpha multiplier for opacity control.

    Protected Internal_enable

    _enable: boolean = true

    Internal state tracking enabled/disabled status.

    Protected Optional Internal_materialSet

    _materialSet?: StateMaterialSet

    Internal reference to the material set.

    hoverPointerIds: Set<number> = ...

    Set of pointer IDs currently hovering over the object.

    Tracks all pointer IDs that have entered the object area but not yet left. Used for multitouch hover state management. Multiple pointers can simultaneously hover over the same interactive object.

    interactionScannable: boolean = true

    Controls whether this object is scannable by MouseEventManager during interaction detection.

    When false, MouseEventManager will skip this object during checkTarget() processing, preventing it from receiving any pointer events. This is different from enable/disable which only affects handler-level processing.

    true
    pressPointerIds: Set<number> = ...

    Set of pointer IDs currently in pressed state.

    Tracks all pointer IDs that have triggered down events but not yet corresponding up events. Used for multitouch support and same-ID click detection. The Set automatically prevents duplicate pointer ID storage and provides O(1) add/delete/has operations.

    state: ClickableState = "normal"

    Current visual interaction state of the object.

    Represents the current state used for material selection:

    • normal: Default resting state
    • over: Pointer hovering over the object
    • down: Pointer pressed down on the object
    • disable: Object is disabled and non-interactive
    value: undefined | Value

    Arbitrary data associated with this interactive object.

    The value property allows association of custom data with the interactive object, making it useful for identifying specific buttons in multi-button scenarios or storing configuration data. Event listeners can use this value to determine appropriate responses to interactions.

    // String identifier
    handler.value = 'save-button';

    // Complex object with metadata
    handler.value = { id: 'btn1', action: 'save', data: {...} };
    view: ClickableView<Value>

    The display object being managed by this interaction handler.

    This readonly reference maintains the connection between the handler and the Three.js display object (Mesh, Sprite, or Group).

    prefixed: string | boolean

    Accessors

    • set alpha(value: number): void

      Sets the opacity alpha multiplier for the material set.

      Parameters

      • value: number

        Alpha multiplier value (minimum 0.0 for transparency, no maximum limit)

      Returns void

      Controls the overall opacity of the interactive object by setting an alpha multiplier that is applied to all materials in the material set. This allows for fade effects while preserving the relative opacity differences between different interaction states.

      Values above 1.0 are permitted to allow compensation for materials with low base opacity (e.g., alpha=5.0 with material opacity=0.2 results in final opacity=1.0). Negative values are clamped to 0.0 to prevent invalid opacity states.

    • get enabled(): boolean

      Indicates whether the object is currently enabled for interactions.

      Returns boolean

      True if the object is enabled, false if disabled

      This getter provides read-only access to the internal enabled state. When enabled, the object can respond to pointer interactions; when disabled, the object becomes non-interactive and displays in disabled visual state.

    • get frozen(): boolean

      Temporarily prevents interaction handling while maintaining current visual state.

      Returns boolean

      When frozen is true, the object stops responding to pointer interactions but preserves its current visual state (does not switch to disable state). Useful when you want to temporarily pause interactions without changing the visual appearance to disabled.

      false
    • set frozen(value: boolean): void

      Parameters

      • value: boolean

      Returns void

    • get isOver(): boolean

      Indicates whether any pointer is currently hovering over the object.

      Returns boolean

      True if one or more pointers are over the object, false otherwise

      Computed from the size of the hoverPointerIds Set. Returns true when any pointer is hovering over the interactive object, supporting both single and multitouch scenarios while maintaining backward compatibility.

    • get isPress(): boolean

      Indicates whether any pointer is currently pressed down on the object.

      Returns boolean

      True if one or more pointers are pressed down, false otherwise

      Computed from the size of the pressPointerIds Set. Returns true when any pointer is pressed down on the interactive object, supporting both single and multitouch scenarios while maintaining backward compatibility.

    Methods

    • Protected

      Calculates the appropriate interaction state based on current conditions.

      Returns ClickableState

      The calculated interaction state

      Determines the correct interaction state by evaluating enable status and pointer conditions in priority order: disabled → pressed → hovering → normal. This method provides consistent state calculation logic used by switchEnable and other state management operations.

      State priority:

      1. If disabled, returns "disable"
      2. If any pointer is pressed, returns "down"
      3. If any pointer is hovering, returns "over"
      4. Otherwise returns "normal"
    • Protected

      Checks if the object is currently active and can respond to interactions.

      Returns boolean

      True if the object is enabled and not frozen, false otherwise

      Determines whether the object should respond to pointer interactions by checking both the enabled state and the frozen flag. An object must be both enabled and not frozen to be considered active.

    • Disables the interactive object, preventing response to pointer interactions.

      Returns void

      Sets the object to a disabled state, making it unresponsive to pointer interactions and updating the interaction state to "disable". This is equivalent to calling switchEnable(false) and clears both pressed-pointer and hover-pointer states.

    • Enables the interactive object, allowing it to respond to pointer interactions.

      Returns void

      Sets the object to an enabled state, making it responsive to pointer interactions and updating the interaction state based on current pointer conditions ("over" or "normal"). This is equivalent to calling switchEnable(true) and, on enable, clears pressed-pointer state while preserving hover state.

    • Return an array listing the events for which the emitter has registered listeners.

      Returns (keyof ThreeMouseEventMap<Value>)[]

    • Return the number of listeners listening to a given event.

      Parameters

      Returns number

    • Hook method called when a click interaction is detected.

      Returns void

      This method is called when a complete click interaction occurs (pointer down followed by pointer up). Subclasses can override this method to implement custom click behavior. The base implementation is empty.

      This method is called before the click event is emitted, allowing subclasses to modify state or perform actions that should occur during the click process.

    • Handles pointer down events and transitions to pressed state.

      Parameters

      Returns void

      Processes pointer down events by checking activity status, adding the pointer ID to the pressed set, transitioning to "down" visual state, and emitting the down event. Supports multiple simultaneous pointers. If the object is inactive (disabled or frozen), the event is ignored.

      down - Emitted when the pointer is successfully pressed down

    • Handles pointer up events and manages click detection logic with multi-touch suppression.

      Parameters

      Returns void

      Processes pointer up events by checking for same-pointer-ID press state, removing the pointer from the pressed set, determining the next visual state based on hover status, and emitting the up event. Click events are only triggered when the same pointer ID was previously pressed down (same-ID click detection).

      Multi-touch Click Suppression: When a click is triggered, all remaining pressed pointers are cleared to prevent subsequent click events. This matches native browser behavior where multi-touch gestures suppress synthetic click events.

      Browser behavior investigation on iPad revealed that multi-touch interactions naturally suppress click events. This implementation replicates that behavior by clearing the press map after the first successful click, preventing additional pointers from triggering subsequent clicks during the same multi-touch interaction.

      up - Emitted when the pointer is released

      click - Emitted when a complete same-ID click interaction is detected. Only the first completing pointer in a multi-touch scenario triggers this event.

    • Remove all listeners, or those of the specified event.

      Parameters

      • Optionalevent: keyof ThreeMouseEventMap<Value>

      Returns this

    • Remove the listeners of a given event.

      Type Parameters

      Parameters

      Returns this

    • Switches the interactive object between enabled and disabled states.

      Parameters

      • bool: boolean

        True to enable, false to disable

      Returns void

      Changes the enabled state of the interactive object and immediately updates the interaction state and material. When disabled, all pointer states are cleared to prevent stale multitouch interactions. When enabled, only press states are cleared while hover states are preserved to maintain visual feedback.

      Press state clearing on enable prevents unintended click events when a button is programmatically enabled while a pointer was previously pressed down. Hover state preservation maintains proper visual feedback for pointers that are still over the object when it becomes enabled.

      // Enable the button
      handler.switchEnable(true);

      // Disable the button
      handler.switchEnable(false);
    • Protected

      Updates the display object's material based on current state and settings.

      Returns void

      Applies the current alpha multiplier to the material set and retrieves the appropriate material for the current interaction state and enabled status. The material is then applied to the display object based on its type (Mesh, Sprite, or Group).

      This method handles the coordination between the abstract state management and the concrete Three.js material system. Groups are not currently supported for material updates.

    • Protected

      Updates the current interaction state and refreshes the visual representation.

      Parameters

      Returns void

      Changes the current interaction state and immediately updates the display object's material to reflect the new state. This method coordinates state management with visual feedback.

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