Presented as a new technique for rendering floors in FS 22, the parallax occlusion mapping however celebrated its twenty candles. Back to a rendering / mapping method that today relieves our graphics cards and makes our eyes shine.
Giants Software announced the use of parallax occlusion mapping for rendering certain types of soil in Farming Simulator 22. We got a first glimpse of plowed land. And many of you don't know what it is. There is no question here of going into technical details because there is not one but several methods to implement parallax occlusion mapping in a video game.
Remember that this technique stems from displacement mapping, which allows, from a grayscale image, to deform a mesh as in the example below:
This technique makes it possible to carry out fast and detailed modelizations but with the enormous disadvantage of will require a dense mesh. In our example, the Plane is composed of 10.000 polygons, which makes it possible to have material to deform, but can very quickly overload the CPU and the GPU in the context of a real-time display. This is not a method used in the world of video games, where we prefer the use of normal maps, which create a feeling of light relief.
Parallax occlusion mapping, a polygon is worth 10.000
To explain parallax occlusion mapping in the simplest way, it is a method similar in use to displacement mapping. That is to say that we will create 3D (or rather here, an illusion of 3D) from a grayscale map (or a normal map, it also works). The big difference is that here we are going to work on the texture and not directly on the 3D. Displacement distorts 3D, parallax occlusion mapping “distorts” texture.
Concretely, the texture of a face is calculated according to the lighting, the user's viewing angle, and a displacement map. Once this texture has been rendered, it is "replated" on the polygon to simulate the relief. The efficiency, compared to the normal map, is higher. Parallax occlusion mapping is able to mask elements. In the example below, if the camera gets closer to the ground, then the stones in the foreground will hide the stones in the background. And yet, this same ground is made up of only one and only one polygon!
The graphics card is thus relieved in the calculation of the display of the 3D part, since the balance is balanced between rendering of the textures and rendering of the 3D mesh of an object. The efficiency is even better.
This technique will take care of the display of soils in FS22, but it is not yet known whether it will be possible to use it on vehicles or buildings, in order, from an old model, to obtain a little more detail. Wait and see ...
For 3DSMAX users, a plugin in 2003 already made it possible to use this method, it was free and was simply called “Relief Mapping”. Now it's a bit more complicated to implement it. You must use the OSL language when creating textures. You can download the shader from the Racoon Artworks website by clicking here. The story does not say if this method will work with FS 22, or if Giants Software plans to provide a simplified export module.