A heightmap is an image that defines the landscape of your game. Keep in mind that your game doesn’t necessarily need a heightmap, but they are perfect for driving, racing, and role-playing games.
Heightmap images are made in Grayscale mode, which means that there is no color in them, but just 256 shades of gray. You can create mountains and valleys and plains in a heightmap through the use of different shades. Anything that is fully white represents the highest peak, whereas anything that is completely black represents the lowest point (see Figure 8.1).