Bg2MouseEvent

The Bg2MouseEvent class represents mouse input events in the bg2 engine TypeScript API. It extends EventBase, providing support for event propagation control.

This class encapsulates mouse interaction data such as button state, cursor position, and wheel delta, while also exposing the original native browser event.

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Enums

MouseButton

Defines the mouse buttons:

export enum MouseButton {
    LEFT = 0,
    MIDDLE = 1,
    RIGHT = 2,
    NONE = -1
}

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MouseButtonEventType

Defines the type of button event:

export enum MouseButtonEventType {
    NONE = 0,
    UP = 1,
    DOWN = 2
}

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Constructor

constructor(button?: MouseButton, x?: number, y?: number, delta?: number, event?: any)

Creates a new mouse event instance.

Parameters

• button: Mouse button involved in the event
• x: Cursor X position (canvas-relative)
• y: Cursor Y position (canvas-relative)
• delta: Wheel delta value (used in wheel events)
• event: Original native browser event

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Properties

button: MouseButton

Mouse button associated with the event.

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x: number

Horizontal position of the cursor relative to the canvas.

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y: number

Vertical position of the cursor relative to the canvas.

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delta: number

Scroll delta value for wheel events.

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event: any

Reference to the original native mouse event.

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Utility Functions

createMouseEvent(evt: any, mainLoop: any, buttonType: MouseButtonEventType): MouseEvent

Creates a Bg2MouseEvent from a native browser event.

This function:

• Updates the internal mouse position
• Updates button state
• Returns a normalized event instance

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Mouse Button State Helpers

These functions provide global access to mouse button states:

• leftMouseButton(): boolean
• middleMouseButton(): boolean
• rightMouseButton(): boolean

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setMouseButton(event: any, status: boolean): void

Updates the internal state of a mouse button.

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clearMouseButtons(): void

Resets all mouse button states.

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Usage Notes

• Used in AppController callbacks such as mouseDown, mouseUp, mouseMove, mouseDrag, and mouseWheel
• Coordinates are always relative to the canvas
• Use delta only for wheel events
• Use event for low-level browser-specific data if needed

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Example

mouseDown(evt: Bg2MouseEvent) {
    console.log(`Mouse down at ${evt.x}, ${evt.y}`);

    if (evt.button === MouseButton.LEFT) {
        console.log("Left button pressed");
    }
}

mouseWheel(evt: Bg2MouseEvent) {
    console.log(`Wheel delta: ${evt.delta}`);
}

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Related Types

• EventBase
• AppController