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Howto:Regional texturing: Difference between revisions
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== Creating good textures == | == Creating good textures == | ||
Good terrain texturing is more of an art than of a science, because there are many different factors to consider. | Good terrain texturing is more of an art than of a science, because there are many different factors to consider. | ||
=== What makes a good texture sheet? === | |||
To get visuals of a region close to reality, you might want to start with aerial imagery of the regions and extract textures from there - but that is not without pitfalls. | |||
The texture needs to be GPL compatible. While there are some public-domain aerial imagery data bases, the most popular (Google Earth) is not. I've also made surprisingly good experience in looking for aerial imagery from local photographers and asking their permission to extract a texture from their work. | |||
The biggest problems of textures are too much structure and lack of structure. If there is lots of structure in a texture, once you map the same sheet to a large area you get pronounced tiling: | |||
[[File:Domains_agro01.jpg|400px|Tiling in agriculture]] | |||
Tiling like this is very prominent from high altitude, it is one of the visually least appealing features and should be avoided at all cost. If the base texture layer has much less structure, tiling is also much less apparent: | |||
[[File:tiling_example.jpg|400px|An example for texture tiling]] | |||
On the other hand, the more the structure inside a texture sheet is de-emphasized, the more prominent is also the appearance of the landclass boundaries where the texture sheets change: | |||
[[File:Egph_egeo3.jpg|400px|An example for landclass seams]] | |||
The ideal texture sheet is a compromise between these two extremes - structured enough to de-emphasize landclass boundaries, not so structured as to lead to bad tiling. | |||
Another thing to consider when extracting a texture from aerial photography is that the land may be often dusty on the photograph. That is problematic because in FGs texturing scheme we want to be able to [[http://wiki.flightgear.org/Procedural_Texturing#Dust add dust procedurally]] which only works if the base texture is sufficiently clean. | |||
So you may have to work with an image processing software to adjust hue and contrast of a texture sheet after taking it from a photograph, and run a mapping algorithm to make sure it does not generate seams when repeated. | |||