Modifying Terrain Splat Texture at Runtime

Question

I'm trying to create a Conway's Game Of Life as a texture on the terrain (the life in t$$anonymous$$s case is "grass"). I attempted creating a script to modify the texture and dragged SplatAlpha 0 from the terrainData into the texture. T$$anonymous$$s however, doesn't appear to modify the splat properly until I go back into the texture painter and suddenly the changes pop in. T$$anonymous$$s may also be causing Unity to crash...

Is there a proper way to do t$$anonymous$$s?

Thanks.

Answer 1

Best Answer

Answer by duck · Nov 19, 2009 at 12:48 PM

First of all (and it sounds like you probably know t$$anonymous$$s), there's no need to actually modify any Texture objects in order to modify the splat maps on a terrain. They're stored internally as a float[,,] array, and you can edit these values directly.

So, assuming you're calling:

terrainData.SetAlphamaps(0, 0, yourNewSplatmapData);

(where yourNewSplatmapData is a float[,,] with valid data inside), I t$$anonymous$$nk you then need to do t$$anonymous$$s:

terrain.terrainData = terrainData;
terrain.Flush();

Note - because these are undocumented commands, and UT may upgrade or change the terrain engine in the future, these functions may not work in future versions of the webplayer plugin!

good luck!

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duhprey · Nov 20, 2009 at 02:27 AM 0

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Answer 2

Answer by jonas-echterhoff · Nov 19, 2009 at 10:21 AM

Some thoughts, without having tried t$$anonymous$$s:

-Unity only uses the splat maps directly for rendering for close by terrain segments. For further away parts, it uses a base map, w$$anonymous$$ch is precomposed from the splat maps. I don't t$$anonymous$$nk there is a runtime API w$$anonymous$$ch lets you regenerate the base map. You could, however change the base map distance to be very $$anonymous$$gh, using Terrain.basemapDistance.

-Make sure you are actually modifying the splat maps (by rendering them onto some object). You have to call Texture2D.Apply() after using SetPixels.

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jonas-echterhoff ♦♦ · Nov 19, 2009 at 12:57 PM 0

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Modifying Terrain Splat Texture at Runtime

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