Lighting the scene with emissive materials
We used lights in previous recipes whenever we needed to illuminate a scene. You might remember what we did in Chapter 1 when we explored the Image Based Lighting (IBL) technique. Lights are one of the key types of actors within Unreal, and their importance is critical within the rendering pipeline. We wouldn’t be able to see much if it wasn’t for them!
Having said that, the engine puts another interesting option at our disposal whenever we need to light a level: emissive materials. As their name implies, this type of shader allows objects to emit light, helping us shade the levels we are creating differently.
Of course, they come with their own set of pros and cons: on the one hand, they allow us to use custom 3D models to light different areas, enabling interesting-looking effects such as neon lights or light coming from TV screens – something that would prove quite difficult to tackle using standard lighting techniques...
