getCursorNDC( cursorX, cursorY, canvas ) {

		const canvasRect = canvas.getBoundingClientRect();
		this._v2_1.setX( ( ( cursorX - canvasRect.left ) / canvasRect.width ) * 2 - 1 );
		this._v2_1.setY( ( ( canvasRect.bottom - cursorY ) / canvasRect.height ) * 2 - 1 );
		return this._v2_1.clone();

	}
Calculates the cursor position in NDC.

@private
@param {number} cursorX - Cursor horizontal coordinate within the canvas.
@param {number} cursorY - Cursor vertical coordinate within the canvas.
@param {HTMLElement} canvas - The canvas where the renderer draws its output.
@returns {Vector2} Cursor normalized position inside the canvas.