→The dirt runway effect
(i.e. setting a parameter to 100 means that the texture sheet is supposed to represent a 100 m x 100 m patch of runway). This is different from the way the default renderer treats dirt runways by stretching the assigned texture over the whole runway (i.e. texture magnification depends on runway size). The strength of the grain overlay can be controlled by
where a value of zero implies no grain texture and a value of 1 the full grain effect as on the texture.
is set to 1, the noise distribution will tend to favor the base layer in the center of the runway. <b>This requires a specific uv-mapping and will not work for custom-generated runways.</b> The strength of that bias is set by
which is between 0 (no bias) and 1 (don't draw overlay layer in runway center no matter what).
In addition, the effect uses a normal map (since it is used in a non-standard way, touch at your own risk) - the visual 'bumpiness' of the runway can be adjusted using
Using different mixtures of textures and parameters, a wide variety of visuals can be achieved, a few examples in the following.
A lakebed texture overlaid with sand gives proper visuals for e.g. the Rogers Dry Lake runways at Edwards AFB:
Using a largely grass-textured surface and allowing some gravel to show in the runway center gives the appearance of a worn grass runway:
Using the effect 'as is', i.e. without any additional parameters, reproduces the old appearance of the dirt runway effect in ALS:
With the original dirt runway texture mapped to a small size and framed by less structured dirt, also a compelling result can be achieved:
Using grass as the overlay material blends the runway outline nicely into the airport keep:
Finally an example of diffuse sand patches blended into each other by low frequency noise and a large value of the transition in the filter:
=== Overlay layers ===