LogInWe’ve partnered with the wonderful people from Konami’s PES Graphics Team and discussed how the lighting is produced in Pro Evolution Soccer (PES).
Lighting in games has been one of the few things that are constantly evolving. This year, we’ve seen a lot of special attention paid to real-time lighting, making it one of the hottest topics on discussion boards. Taking into consideration the relevance of lighting tech, we’ve partnered with the wonderful people from Konami’s PES Graphics Team and discussed how the lighting is produced in one of the most popular soccer game series – Pro Evolution Soccer (PES).
Lighting in Sport Games
Light in games is usually a tool to build the mood. Little dim lights fit spooky corridors, red lights fit the environments of hell, and brightly lit spaces often feel cheerful and optimistic. With sports games though, it’s a little bit different. In games like PES, the lighting is produced mostly to achieve better realism and show the popular sport in its full glory. The main goal is to bring the visuals as close to the television image as possible.
Building truly realistic lighting in a real-time scenario with an increasing demand for more content can prove quite difficult sometimes.
“When we are working with real-time graphics one of our main focuses is finding the right balance between quality and performance. But sometimes we, the graphics programmers, can get carried away and forget about productivity, iteration, adaptability, etc. That’s why we keep reminding us that it’s important to understand what the artists need and develop the technology for them, not just for our own needs” — PES Graphics Team
With any development, not just PES, the conflict between tech and art continues to be one of the biggest problems for game developers. Finding the perfect technology to help build a good lighting in a real-time sports game is extremely difficult, especially since there are such challenging technological requirements.
“At the end of the day, we also need to put emphasis on optimization. In the last few years, we reshaped our engine to maximize performance for our specific requirements while we simplified our graphics source code to improve flexibility and to reduce potential bugs. We are now also using dynamic resolution and a state of the art temporal-spatial upsampler for all our platforms. This was the most significant optimization effort but we did not stop there; our graphics pipeline is periodically checked in search of bottlenecks and optimization opportunities. When we find something strange we analyze it right away and, if possible, take actions as fast as we can.” — PES Graphics Team
Lighting in PES
“Technically speaking, the PES lighting system is nothing special in itself. It consists of a typical Deferred rendering pipeline and a physically based shading model.
We focus instead on enabling the creation of as many higher quality assets as possible within a short amount of time. We accelerated iteration and allowed artists to spend more time doing what they love – art.” — PES Graphics Team
With every new release game developers faced with new problems. With the latest PES game, the core requirements were:
- 60FPS with no frame drops
- Support rendering at 4K/HDR on all capable platforms
- Support various times of day and weather variations
- The game image must be as close as possible to the actual stadium reference pictures.
To achieve the last two goals, the developers had to find a solution for faster iteration. They were required to build a faster content production pipeline, to let artists have more control and flexibility without being hampered by the technical challenges.
“Until PES2018, our engine had also targeted PS3 and Xbox 360, so it was not perfect at handling realistic lighting, and it did not show ideal results while working with global illumination.
Because our illumination pipeline was designed to run efficiently on PS3 and Xbox 360 the results do not reach satisfactory quality levels without first some tweaking. As a result, our small team of lighting artists had to perform plenty of manual adjustments for every scene and weather condition. Our working hours increased and our schedule became desperately tight.
In the past, we had used other global illumination solutions such as baked lightmaps but we had to go through increasingly long bakes. Even small modifications in our content would cost many hours among other problems.
Although PES has mostly outdoors scenes, the stadium roofs generate big predominant shadows. Under these shadows, the illuminance balance, shadows gradation and accurate contrasts are very important. Regardless of the solution we had tried, the artists were forced to add extra lights to improve the illumination in these areas, giving them even more work to do.
Many approaches can be used to model GI and they all in theory output approximately correct results. We believe the key here is not to choose the solution the graphics programmers like best, but to choose the workflow which will allow our artists to work comfortably and create images as they are intended.
After a lot of thought, we decided to replace our global illumination pipeline with a dynamic solution, which was already available on the market. This is when we started thinking more about Enlighten”. — PES Graphics Team
Enlighten
Enlighten is a widely used solution for low cost and high-quality real-time GI. If played RiME, you’ve seen what it can do.
Most importantly, Enlighten offers fast iteration and a simple workflow. Real-time lighting updates mean instant feedback on lighting changes. More iterations in less time should enable the lighting artists to produce their best work.
While many real-time GI solutions make heavy use of the GPU, Enlighten requires close to zero GPU time even at high display resolutions. This means graphics programmers can use the spare GPU time to improve image quality and responsiveness.
Enlighten simulates multiple light bounces to produce realistic lighting even in shadowy enclosed areas. All this has no impact on the game frame rate because the simulation runs as a background task.
“Enlighten uses math known as Spherical Harmonics and an octree data structure to efficiently encode lighting data across a large volume of space. In the engine, Enlighten gives us lighting data in the form of a 3D virtual texture. It’s simple and inexpensive for us to use this texture to apply the diffuse GI when rendering.
Before, to distribute diffuse GI data throughout the space, artists would have to carefully place many GI volumes. Instead, Enlighten automatically determines where to place the diffuse GI data, giving us more accuracy only where it’s needed This saved the artists a lot of time”. — PES Graphics Team
The Benefits of New Lighting Solution
“In the last few years, we went to several stadiums to take plenty of reference data, including aerial references from helicopters. All this information allows us to match almost all our game cameras with the real counterparts.
There were also technical improvements in other areas of the graphics pipeline that complemented our lighting system perfectly. For example, we have increased the texture information density significantly, reduced illumination artifacts (like specular aliasing) and improved temporal stability, just to name a few things. And of course, we plan to keep improving our engine to increase the realism of our lighting even further.
Finally, our illumination artists had iterated several times until they were able to adjust the lighting to their liking. Producing great lighting is a group effort and everyone gave their best.
For PES 2019 we produced high-quality artist-friendly indirect lighting by using Enlighten.
We got rid of the extra manually placed lights and other annoying and unnecessary complications. Even things like camera exposure can now be controlled more easily.
One final anecdote: our artists had always wanted to blend the stadium lights with the GI of the sunset on summer nights. Now, with our new lighting solution, they were finally able to do this, producing stunning illumination. This kind of things looks awesome and motivates us to keep pushing our limits.”— PES Graphics Team