Although SpriteKit adds a normal map on its own, you can also specify your own normal maps for better results. To download Sprite Illuminator, go to https://www.codeandweb.com/spriteilluminator and download the DMG file.
Once Sprite Illuminator has been downloaded, double-click on the DMG file and copy the application to the Applications folder. Go to the Launchpad and start the application. Once the application launches, you should see the window as in the following screenshot:
Let us look at the interface in detail.
On the left, we have the Sprites panel. The middle panel is the Preview panel, in which you can see a preview of ...