Enlightening Worlds: Illuminating Scenes with the Universal Render Pipeline

Lighting is a complex topic and there are several possible ways to handle it, with each one having its pros and cons. In order to get the best possible quality and performance, you need to know exactly how your renderer handles lighting, and that is exactly what we are going to work on in this chapter. We will discuss how lighting is handled in Unity’s Universal Render Pipeline (URP), as well as how to properly configure it to adapt our scene’s mood with proper lighting effects.

In this chapter, we will examine the following lighting concepts:

• Applying lighting
• Applying shadows
• Optimizing lighting

At the end of the chapter, we will have properly used the different Unity illumination systems like direct lights and lightmapping to reflect a cloudy and rainy night.

Applying lighting

When discussing ways to process lighting in a game, there are two main ways we can do so, known as Forward rendering and Deferred rendering, each having some variants. Both handle lighting in a different order, with different techniques, requirements, pros, and cons. Forward rendering is usually recommended for performance, while Deferred rendering is usually recommended for quality.

Also, in Unity, the Forward Renderer comes with three modes: Multi-Pass Forward, which is used in the Built-In Renderer (the old Unity renderer), Single-Pass Forward, which is used by default in URP, and Single-Pass Forward+, the only form of Forward that HDRP (High Definition Render Pipeline) supports, as well as an option for URP. We have several modes because each one has different characteristics and limitations, making them ideal for different types of games.

Choosing between them depends on the kind of game you are creating and the platform you need to run the game on....

Applying shadows

Maybe you are thinking that we already have shadows in the scene, but actually, we don’t. The darker areas of the object, the ones that are not facing the lights, don’t have shadows—they are not being lit, and that’s quite different from a shadow. In this case, we are referring to the shadows that are projected from one object to another—for example, the shadow of the player being projected on the floor, or from the mountains to other objects.

Shadows can increase the quality of our scene, but they also cost a lot to calculate, so we have two options: not using shadows (recommended for low-end devices such as mobiles) or finding a balance between performance and quality according to our game and the target device.

Figure 12.22: Area 1: an area not being lit because it doesn’t face the light. Area 2: an area not being lit because it is shadowed by the other cube

In this section, we are going to discuss the...

Optimizing lighting

We mentioned previously that not calculating lighting is good for performance, but what about not calculating lights, but still having them? Yes, it sounds too good to be true, but it is actually possible (and, of course, tricky). We can use a technique called static lighting or baking, which allows us to calculate lighting once and use the cached result.

In this section, we will cover the following concepts related to static lighting:

• Understanding static lighting
• Baking lightmaps
• Applying static lighting to dynamic objects

Understanding static lighting

The idea is pretty simple: just do the lighting calculations once, save the results, and then use those instead of calculating lighting all the time.

You may be wondering why this isn’t the default technique to use. This is because it has some limitations, with the big one being dynamic objects. Precalculating shadows means that they can’t change once they...

Summary

In this chapter, we discussed several lighting topics, such as how Unity calculates lights and shadows, how to deal with different light sources such as direct and indirect lighting, how to configure shadows, how to bake lighting to optimize performance, and how to combine dynamic and static lighting so that the lights aren’t disconnected from the world they affect. This was a long chapter, but lighting deserves that. It is a complex subject that can improve the look and feel of your scene drastically, as well as reduce your performance dramatically. It requires a lot of practice, and here, we tried to summarize all the important knowledge you will need to start experimenting with it. Be patient with this topic; it is easy to get incorrect results, but you are probably just one checkbox away from solving it.

Now that we have improved all we can in the scene settings, in the next chapter, we will apply a final layer of graphic effects using the Unity post-processing...