https://wiki.splashdamage.com/index.php?action=history&feed=atom&title=DecalsDecals - Revision history2026-04-07T18:53:47ZRevision history for this page on the wikiMediaWiki 1.31.0https://wiki.splashdamage.com/index.php?title=Decals&diff=3321&oldid=prevDucks: Batch update2007-11-21T15:30:29Z<p>Batch update</p>
<p><b>New page</b></p><div>Decals - such as wall stains, cracks and marks - are semi-transparent textured patches placed just slightly in front of world geometry. Using decals adds variety to the monotony of plain, tiled textures, and also help visually integrate [[map objects]] with world geometry.<br />
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== Example ==<br />
[[Image:decals_building.jpg|frame|none|Before and after example of using decal patch meshes to 'dirty-up' a building, breaking up the repeating textures.]]<br />
[[Image:decals_bridge.jpg|frame|none|Island's bridge uses a MD5 decal model]]<br />
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== Usage ==<br />
# Create a [[Brush Basics|patch]] for the decal to appear on.<br />
# Use the Media Browser to find an decal texture for the patch (search for 'decal')<br />
# Move the patch so it is flat against a wall<br />
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[[Image:decals_usage.jpg|frame|none|Using a textured patch placed flat against a wall as a decal.]]<br />
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* Note: some decals require that the patch be placed slightly away from the wall (0.5 units or so) in order to avoid z-fighting. This can be countered by using decals with the 'polygonoffset' parameter set.<br />
* Note: most decals don't contribute to the collision mesh, but it is always wise to turn off their 'Solid Collision' flag in the Primitives inspector.<br />
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== Material Setup ==<br />
Since decals are non-collidable, (usually) transparent, placed flush against walls and don't cast shadows, they need a special material setup in order to appear correctly in-game. <br />
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For example, here's the definition in {{filename|decals_new.mtr}} for the {{filename|textures/decals/decal14}} texture in the usage example above:<br />
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material textures/decals/decal14<br />
{<br />
sort decal<br />
polygonoffset<br />
nonsolid<br />
translucent<br />
{<br />
blend filter<br />
map textures/decals/decals_14_d.tga<br />
}<br />
}<br />
<br />
Its parameters are fairly self-explanatory:<br />
* <tt>sort decal</tt> - ensures the renderer sorts faces using this texture with other decals<br />
* <tt>polygonoffset</tt> - 'lifts' the decal away to prevent z-fighting<br />
* <tt>nonsolid</tt> - so the decal won't contribute to the collision hull (to stop the player getting caught on it)<br />
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* See [[Materials]]<br />
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== See Also ==<br />
* [[Brush Basics]]<br />
* [[Detail Groups]]<br />
* [[LOD Groups]]<br />
* [[Materials]]<br />
* [[Map Objects]]<br />
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[[Category:Basic Level Design]]</div>Ducks