A Look into Lighting for Games

As hinted above, I’ve been playing games since I was 6 years old. Even if as a kid I didn’t realize I could make a living out of that (the industry was not really there at that time either) I always have been super into games. When I reached university there were not that many options to study games development yet (only 1-2 schools in France) so I enrolled in a more general degree (multimedia creation) and taught myself 3D on the side. Even if it was tough to go that way, in the long run, it allowed me to have a lot more versatility and adaptation skills due to some knowledge/experience in other specialties like programming, scripting, marketing, networking, management, etc.

Goals

When I decided to join the class Art of Lighting for Games I already had quite a lot of experience in lighting games. Still, I wanted to hear from an experienced industry specialist about the best practices and how he was approaching lighting, especially for AAA titles. I was mostly self-taught and I was not sure whether my approach was the best. It was also a great way to push myself by having some deliverables (one scene to light per week for ten weeks) and rapidly improve my skills.

Even though what we are taught in the class can work in every engine, it was a great chance for me to also get my hands on Unreal Engine which I had not used in a very long time.

Organization of the Class

Every week we were given a scene in which all the lights had been removed and we had to light it from scratch while following some very broad guidelines like “do a night scene”. The subjects were varied (interior, exterior, RTS game, multiplayer game, cinematic cutscene, etc.) so we got prepared to a wide range of challenges and their specific constraints – the same thing we could get in a real game production environment. While having a broad direction (and being shown one approach to it during the class), we still had a lot of liberty in the ways to work on our scenes. It resembles a game production scenario where the lighting artists are usually entrusted with their work and have some leeway in how to make the best out of it. Omar (the instructor) encouraged us to take risks and to try / suggest different approaches.

Lighting Workflow

A good starting point is always a solid collection of references for what you want to achieve. These references could come from concepts, movies, photographs, paintings or even other games as long as they give you a direction and an idea about how the light would affect your scene. Having a good moodboard also helps to sell your ideas to other people who you would work with during real production.

Once you have an idea about what you would like to achieve it’s important to start broad and get solid foundations rather than immediately focus on small details. A typical workflow would be to start with the sky which provides the overall mood for your scene and fill everything with some basic light values. I usually use HDR sky captures for that (more details will come later) and do not hesitate to edit the HDRI in photo image editing software if needed. Once I’m happy with the global light, it’s time to add a directional main light source (the sun for the exterior or your main light for the interior – which could come from the windows, for example) and to tweak its intensity and position until you get interesting highlights and shadows. At this point, if your HDRI sky has a strong evident light source it’s always wise to rotate it until it matches your main directional light source.

These two light sources are the most important things to nail when doing exterior lighting. In almost every case, if your initial setup is off there is no point in tweaking other things. Also, with just these two things done right, you can already have a very appealing image.

At this point, if your scene is supposed to be a part of any kind of foggy environment, it would be a good idea to add some fog as it will help set the overall mood. It’s quite often an easy and beneficial addition to make a scene more visually interesting.

Set up some basic reflection probes, so that the reflective material is rendered properly. Once you are happy with what you have you can start to add more secondary and fill lights. For video games, it’s important to keep in mind the gameplay and make sure the environment is easy to read and the light is leading the player toward the right things. If you have a bright spot outside of the golden path (where you want the player to go) it could distract the player and lead him toward an uninteresting area (which would be a false call). Take time to refine your reflections by adding more localized probes when needed.

Now it’s time for the cherry on top of the cake: the post effects. There’s plenty of them and it’s important not to add them too early as they could make you lose focus on solid foundations. However, they are very helpful in setting the right mood. A big part of post effects is directly related to the lighting artist work. The most useful ones for your scene mood would be Tone Mapping, Exposure, Depth of Field, and Bloom.

Building Up Your Visual Library

I don’t have any readily created library of values as any scene is different and the values can greatly change depending on the setup of the scene. There’s a lot of cheating involved in environment lighting in order to achieve good results while maintaining smooth performances and there’s not just one right way to approach a scene lighting.

However, having a good library of HDRI skies is very helpful in getting the right mood for a scene. They really help to give that first pass on a scene lighting and the more you have the more options are available to you. There’s quite a lot of them available for free online, so it’s just a good habit to keep an eye for new good things and save them when you find some. Otherwise, there are some libraries you can buy online or you could even capture HDR skies by yourself with any decent camera and a tripod.

With practice and experience, you get a good sense of what a correct value is and you tweak everything as you go from your main light source to all the small filling ones. It’s more of a repeating and time-proven process which guides you toward the final lighting – the same way a painter starts with broad strokes and finishes with small details. During the class, we were provided with the example scenes from the lecturer so in case of a problem we could always have a look at how he approached them.

Stylized Game Environment Task

Stylized environments offer more creative liberty and it was very welcomed to have it for a change during the class. The setup of a stylized scene was very different from what we worked on before. For this specific exercise, there was a strong gameplay constraint as the scene is used for a Tower Defense like environment. The path must remain the central focus of attention, but at the same time, the units walking on it during gameplay must remain very visible.

The original scene was lit with lava (red / orange color scheme), but I decided to try something else. In that specific case, I didn’t really use photo references (acid lava pits are not that common!) but rather used my judgment to determine how to light this environment. I decided that the main light source would be the lava pit with glowy fumes coming out of it. The light beams coming through the ceiling of the cave were used to brighten the path and the top of the rocks. The key here was to make sure all the colors worked well together and to create some light pools along the gameplay path. If evenly lit, the path would have not caught the player’s attention that much and this alternation of bright and darker spots was key in getting interesting lighting. A useful technique I used here is to temporarily remove any saturation on the render (you can use tonemapping for that or just take a screenshot and bring it to your favorite photo editing software) and check my brightness values on the overall image. Balancing lighting is not just about colors saturation, it’s also about brightness/darkness. These values are very important to check whether the image is well-balanced.

The lava pits are lit with omni lights surrounded by fog. By increasing the amount of light scattering through the fog it creates these thick pools of light which give the toxic feel to the lava and help to sell the diffuse and spreading light effect.

The same principle has been used for the level entrance and exit gates. I used a super strong spotlight coupled with some fog to create those cones of foggy light getting out of the gates and put the emphasis on those important gameplay elements. The lack of color saturation helps them stand out from the rest as well.

Interior Lighting Task

This scene was a bit tricky to tackle as the light volumes were quite big compared to the amount of light I managed to get through the windows naturally. It required the use of quite a few fake lights to simulate bouncing light rays and keep the area easy to navigate (once again, we were doing a video game scene and gameplay had to come first).

In the corridor, I took the liberty to open the ceiling arch which was originally closed in order to bring a complementary color (blueish light source) and make the scene more visually appealing. That’s the kind of calls lighting artists should go for and discuss with other artists on a regular project. As the amount of light naturally coming from the outside was not that intense, I added a spotlight right outside of the newly created window and cranked its value. In order to reinforce its visual impact, I also added some light ray billboards and dust particles floating in the corridor. In the end, they help a lot breaking the symmetry in the corridor layout and catch the player’s attention.

Like in the previous scene (and all the lighting I do), one of the key things to keep your focus on is the alternation of bright and dark areas. It brings some rhythm in your light composition and makes things a lot more interesting in the end. You should never feel restricted by the light sources visible in your scene and feel free to add more if it helps increasing visual quality. The same is done in movies: if the movie makers were only using the real light sources visible, the lighting would not be interesting in their scenes. There’s always a lot of reflecting panels and light sources hidden outside of the camera frame. And it’s exactly the same in video games. If (for example) an area is too dark, feel free to add a soft light to brighten it. Completely black and white spots are something you usually need avoid.

Feedback

I really enjoyed the Art of Lighting Games class. The personal feedback videos we got on every completed exercise were really helpful in pushing our skills to the next level. The exercises were varied enough to make me confident that I could tackle a wide range of different games as a lighter. The class also assured me that the approaches I was using to make my lighting were correct and the pieces of advice on key things given by a specialist will be very valuable in the future of my career.

I also really enjoyed the fact that we have access to other students’ works and video reviews. Every person in the class had their own take on the same subject and it was very instructive to see how it worked out. It also highlights the fact that there’s not just one right solution on how to properly light a scene.

To finish, here is a video from one of the course’s most challenging exercises. The lighting of a cutscene: