After a level is created, its look can be moderated by an art director to have a certain color tint, blur, bloom, or intensity. This is conducted through simple post-process filtration. We will be discussing the features of PostProcess and we'll also discuss lighting approaches and their features, including custom lens flares, types of shadows, ambient occlusion, God Rays and light types, and their settings for achieving nice illumination under different conditions.
In this chapter, we'll cover the following topics:
- Emissive lighting
- Comparison of static and dynamic lighting
- Light exclusivity using channels and levels
- Adjusting shadows through light environments
- Distance field shadows
- Penumbras and hotspots
- Accessing the main PostProcessChain
- Ambient occlusion
- Depth of field
- Ensuring shadows work with translucent or alpha based materials
- Enabling and controlling light shafts
- Enhancing sunrays using lens flares
- Creating caustics using projected imagery
- Translucent colored glass
Lighting in UDK is built around real-time requirements. Epic Games provides the neatest explanation of the features that UDK includes in terms of Rendering, Shaders, and "Eye-Popping Lighting and Shadows" on their front page at http://www.UDK.com/features.
- Illuminate
UDK gives you all the options to perfectly light any scene. Ambient occlusion, per-pixel lighting, fill lighting, and fully dynamic specular lighting and reflections are all possible.
- Unreal Lightmass
Unreal Lightmass is an advanced global illumination solver, custom built to fully take advantage of all that Unreal Engine 3 has to offer. Light your world with a single sun, give off soft shadows, and let the diffuse inter-reflection (color bleeding) do the work.
- Detailed Shadows
Advanced shadowing with support for three techniques:
- Dynamic characters casting dynamic soft shadows.
- Ultra high-quality and high-performance pre-computed shadow masks.
- Directional light mapping with static shadowing and diffuse normal-mapped lighting. An unlimited number of lights can be pre-computed and stored in a single set of texture maps.
Scene lighting that you can put to work immediately is one of UDK's biggest perks. This area does however require some familiarity with the parlance of CG lighting and rendering. A good place to start would be the UDN documentation on lighting in UDK at http://udn.epicgames.com/Three/UDKLevelCreationHome.html.
Here are some of the terms that you would want to explore immediately:
- Lightmass—The Global Illumination system for UDK.
- DominantLight—Helps you set up a direct sunlight. Normally just one is used.
- PointLight—Omni-directional light for artificial lighting, fills, and local lighting.
- LightEnvironments—Used to optimize dynamic object lighting.
- Modulated Shadows—The default shadow type.
- Distance Field Shadows—A newer type of shadow.