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ALS infrared vision: Difference between revisions
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→Preparing models for IR vision
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== Preparing models for IR vision == | == Preparing models for IR vision == | ||
In order to make an object appear at the correct temperature in IR vision, you need to tell the Shader the approximate temperature difference to the ambient air temperature. | |||
All objects are assigned by default one of six daily temperature cycles maintained by Advanced Weather based on time and weather situation (rock, soil, water, vegetation, cloud, structure), i.e. the effect declaration uses a line like (for rock): | |||
<syntaxhighlight lang="xml"> | |||
<delta_T><use>/environment/surface/delta-T-rock</use></delta_T> | |||
</syntaxhighlight> | |||
In a derived effect, you can either assign one of these cycles, or, if the object has an internal heat source, assign a parameter of your choice. For instance, to make an airplane fuselage 10 degrees hotter than ambient air, use | |||
<syntaxhighlight lang="xml"> | |||
<delta_T>10.0</delta_T> | |||
</syntaxhighlight> | |||
(the currently usable range for the parameter is about -10 to +10, much hotter or colder objects would need a special treatment in the shader). | |||
== Known limitations == | |||
The IR vision has no dedicated fogging model. For modest amounts of haze that's not an issue because IR vision can penetrate haze much better than optical vision, but for strong wet fog this gives an unrealistically good IR visibility. Because the contrast between cold sky and warm terrain is never hidden, the implication is that in low visibility the edges of the terrain tiles become visible, especially if you fly too high. | |||
Any object which by its nature can not be assigned into the ALS framework at all (such as particles, ) or is explicitly declared to not use ALS for rendering (such as objects assigned model-transparent.eff) will appear wrong in the IR vision effect, transparent objects should be rendered using model-combined-transparent.eff or glass.eff to show up correctly in all rendering frameworks. | |||
The sophistication of how much thermal physics a shader effect can compute is obviously limited, and any single object may appear implausible as a result. | |||