This is a route we’ve taken with Quake 2. It can be quite revealing to take an old, simple 3D game, and make it a full-path-traced visual experience. This is exactly what Serious Sam: the First Encounter has done. It’s not Serious Sam HD, but TFE. This mod is largely restricted by the restrictions of Serious Sam: The First Encounter’s 2001 release. As you can see, however, it’s impressive to be able to transition into a completely path-traced environment.
Author SultimTsyrendashiev makes extensive changes to the renderer, which runs via Vulkan API. He also modifies the core art assets. Path tracing must work properly and light can propagate through a scene. To do this, the textures have to be updated with normal maps and material value elements. The author of path tracer went in and modified all textures so they had these attributes. It requires a solid understanding of both art and coding. We want materials that look real but still evoke the feel of the original game. Materials are compatible with the path traced renderer and are of much higher resolution.
The video below explains how global illumination works. It also demonstrates the interactions between light and materials. But the bottom line is the GI does not only work on light bounced from the sun, the primary source of light, but can also be used from other man-made sources such as fire pits and torches. The developer faced a challenge when designing interiors. In the original game, there were ‘unmotivated light sources’ placed around levels. These lights are essentially fake lights that provide illumination. These unmotivated light sources are gone in the path-traced game version. They look rather strange when they’re traced. These sections have only light from fire-pits or torches.
Unmotivated lighting is now a problem in many areas. This could be problematic, so the creator of the path-tracing engine included a flashlight for players, similar to the one in Serious Sam 3. These sections now feel different because your flashlight lights up the long-dormant pyramids or crypts casting shadows over the surrounding area.
The path-traced renderinger now includes other light sources, such as power-ups. These can be used to illuminate the surrounding environment and act as emissive surface. Dynamic lighting flares are produced with each shot and every explosion. Mini-gun muzzle flash weapons create a dance of shadow and light around the area. Green laser bolts also do the same thing and every rocket explodes as it flies away. The extra show when you fire weapons makes it more impactful, since the original guns were not well-known for their incredible animations and sound.
Transparent surfaces like water are a final touch. Water surfaces in the original Unreal were identical to the ones used in the game. They featured hyper-blue textures that mimicked water and had blue lights nearby. This was to emphasize the watery appearance. The engine’s path-traced version now has water fully reflective, capturing both the surrounding environment and the sky. Also, water reflects objects in realistic ways when you look through it. The game doesn’t support ray traced caustics in the water like Minecraft RTX. Instead, animated textures are used.
It’s a stunning overall result. The game achieves its overall goal of blending realism and originality well. There are some problems. For example, metallic materials such as metal may appear grainy in low-level lighting or complicated light paths. This makes them sparkle less convincingly, the higher you get down on the resolution ladder. Because the path tracer doesn’t have any volumetric representations for light transport, the fudge volumetric approximation is gone. The game also has no fog. Lens flares, also faked in the original game, are absent in the path traced version. Instead of post-process bloom they have been removed. Although this bloom is great for adding depth to scenes, some people may find it too intense. However, there are ways to adjust the intensity.
This game can be slow, however, it has a high level of detail culling. The option will remove dynamic objects from RT calculations. However, this game is path-traced, so objects may disappear in the distance. The setting can have a high to moderate impact on GPU performance. This is based on an RTX3090 running at 1440p. Changing the setting to ‘less” improved GPU performance by 15% compared to the ‘full setting. Although it is the most popular option, switching to low increases frame rate by 32 percent. Indoor scenes may see different levels of pop-in. This mod also uses a lot of CPU, so be aware of your processor usage. For gameplay above 60fps, you should use the “less” setting on your modern Intel or AMD CPUs.
Many PCs won’t be able to handle this game at high frame rates and high resolutions. An RTX2060 can barely stabilize at 1080p30 even with optimized settings. To achieve 60fps gaming at 60fps, you will need to lower the resolution to 720p. Even then, we are at the edge of stability. An RTX3080 can do the same thing at 1440p with similar settings but with a higher dynamic LOD. Concerning AMD GPUs: I tried to play Serious Sam with a Radeon RX6800XT but the game wouldn’t boot. I also read online that AMD GPUs were not yet fully supported. However, when they do, it will be a great test case. This is similar to Quake 2 RTX. In the absence of Nvidia Lightspeed Studios’ RT remasters, such projects are welcome.
Publited at Thu, 9 Sep 2021 16:18:41 +0000