OpenFL bitmapData.getPixel32 always return 0

Question

I'm trying to find out if there are empty pixels in a certain location using getPixel32 from the OpenFL framework, but it always returns 0.

This is my code:

import { Bitmap, BitmapData } from "openfl";

export default class Tile extends Bitmap {
    constructor(param1: BitmapData) {
        super(param1);
    }

    public isEmpty(x: number, y: number): boolean {
        const pixel32 = this.bitmapData.getPixel32(x, y);
        console.log(pixel32); // return 0
        return ((pixel32 >> 24) & 255) <= 150;
    }
}

My image.png:

Answer 1

An interesting thing, instead of using getPixel32 and using getPixels it looks like it works perfectly:

 public isEmpty(x: number, y: number): boolean {
        return (this.bitmapData.getPixels(new Rectangle(x, y, 1, 1)).get(3)) <= 150;
    }

But I don't know if this is the best method