Normal Maps, on the other hand, do not contain any height information whatsoever. This is pretty computationally expensive, but it can lead to good looking results. An example of this type of displacement is how terrain is often generated from a texture.Īnother use for a displacement map is parallax mapping (also called virtual displacement mapping), which is a more advanced technique in which a game engine attempts to offset the texture coordinates away from the camera. Instead, it is used to generate otherwise complex objects. This kind of displacement doesn't add any additional detail. They are used in the same way as normal maps, except they only contain height information and not angle information.ĭisplacement maps are sometimes used to change the location of actual vertices in a mesh. There are a couple of different types of height maps that you might be familiar with already.īump maps are the old-school way of adding detail to low poly objects. Black is 'down', white is 'up', and 0.5 gray means no change of height.
The most obvious difference is that height maps are greyscale only, because they only portray height differences. While both normal and height maps give our low-poly models the appearance of more detail, they are used for distinctly different purposes. Sounds too good to be true? Keep in mind that there are some limitations to this technique. This allows us to achieve a high level of detail without burdening the game engine with intricate geometry. The light bouncing off a normal mapped surface bounces according to the texture normal instead of the surface normal. How does it work? Normal and displacement maps are special kinds of image textures that influence how light is calculated across a surface. They create an illusion of depth by telling the light to bounce off simulated features of the surface, even though those features are not actually there. The secret is that they allow us to get more apparent detail while using less geometry. Normal maps are the best compromise we have to the struggle between model quality and game performance. So how can we compromise between smooth performance and realistic visuals? Game devs need to be able to use many models in one scene to achieve this, not to mention costly lights, physics, and effects. Low-poly models are needed in order to ensure a game's smooth performance.īut at the same time, gamers expect beautiful visuals with a high level of detail. This means that high-poly models commonly used for 3D printing or animation would not work well in a game, since they would be a huge sap on the game's responsiveness. Games should run in real-time at 60+ frames per second. and why is its use so widespread? Balancing Quality and Performance Triple-A game assets such as Blender characters, weapons, and environments rely heavily on normal mapping in order to look good. But what is normal mapping.
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