Visuals of a game are critical to some players but only a nice extra touch for others. In any case, you as a developer probably have in mind a level of visuals that you want to achieve for your game . Getting there might be difficult. But after sorting out some basics (like better textures and their positioning and compression), there is one more jump in both quality and quality you can easily make. Decals.
“Decals” are a great way to add more visual details, enrich a scene and breakup tiling textures or big surfaces. As the latter was also a topic for us, let me share two examples.
Decals in the first picture add more details to a long corridor. As you can see, adding dirty smudges goes nice with rusty pipes.
Here is an even better example – a simple, small room with little objects in it. Add stains to the wall in the back and the room feels a little less synthetic.
Ok, now the best part. Decals are very easy to use and apply. Perhaps the only limitation is that they can be used on flat surfaces only. But beware – place too many, too large decals and they can have a significant performance impact. This is true especially on mobile devices, where GPU fillrate if often very limited. Use them wisely – where players can really see them.
How does it works (without getting int too much detail)? Adding decals into objects (with this plugin at least) works more like using a brush, you just paint with it over objects. In the background, decals are a simple texture file, just like the base texture on other objects. When the game runs, it adds one more layer to an object.
Decals can use transparency by including alpha channel although this is optional. So you can “paint” even complicated objects on top of any basic texture.
In other words, one of the best 10$ invested :)
A few links on the subject
- Authors of the Unity plugin we have used provide a video overview of what is their plugin capable of: www.protoolsforunity3d.com/quickdecals/ (or as a direct YouTube link: www.youtube.com/watch?v=tielCFE6mg4)
- Official Unity tutorial is a bit shy on the topic: docs.unity3d.com/Manual/shader-NormalDecal.html
- A very informative, practical and explanatory blog post with examples: http://blog.gamesfoundry.com/2012/06/folk-tale-decal-system-overview-in.html
Note: This article is based on our own experience from development in Unity. We would not like to claim it is the best or the only way to approach decals.