So, it works when i use 512x512 textures, but my problem now is (and i don't know if i should open another topic for that) that i need to call the BitmapHelper
tm.addTexture("left",new Texture(BitmapHelper.rescale(BitmapHelper.convert(this.context.getResources().getDrawable(R.raw.left)), 512, 512)));
and rescale my texture to 512x512. The crazy thing is that it is already 512x512.
If i don't rescale it i get a "Unsupported Texture Width: 768" exception.
So i scaled down my texture (in paint) to 341x341 without resizing it with the BitmapHelper and it worked.
How can i still use my 512x512 textures?