Sizable Theft Auto 5’s PC RT enhancements tag at GTA 6 features

Grand Theft Auto 5 for PC has finally received the RT enhancements to achieve feature parity with the next-gen console versions, almost three years after they launched on Xbox and PlayStation systems. The wait was worth it, as the scalability is impressive, and the game also includes the option to enable ray traced global illumination – which may very well hint at the types of RT technologies we can expect to see in the forthcoming Grand Theft Auto 6.

However, let’s be realistic. GTA 5 is nearly 12 years old now, and thus, there are limitations to how significantly improved the game can visually appear. The original was designed around the constraints of the Xbox 360 and PlayStation 3, at least, and that still shines through today, even with the highest-end PC capabilities. Character models reflect their era, while the quality of assets and textures is far from the standard of modern releases. GTA 5 originates from a time before the gaming industry embraced techniques such as physically-based art pipelines and shading algorithms. Although ray tracing can enhance the game in various ways, it cannot match the quality of a brand-new triple-A open-world title.

Nonetheless, these enhancements are welcome. Pre-RTGI GTA 5 is a title that suffers from a common issue many non-RTGI games face, particularly those from this period. Indirect lighting in the original is handled with a clever approach. According to investigations by Adrian Courrèges, the game produces a cubemap from the player’s camera position in real-time, similar to many racing titles. This provides the game with approximate real-time reflections on surfaces like cars, and for rougher textures, the game seems to utilize a filtered variant of that to ensure shadows are not pitch black. The downside is that lighting is only represented from one angle, leading to shadows in GTA 5 appearing gray or overly dark. Everything not exposed to sunlight tends to have a murky gray or almost blue tint, with the edges of geometry adorned with a thick halo of screen-space ambient occlusion.

Ray traced global illumination – not available in the next-gen console versions – is a game-changer here, with lighting bouncing around the environments at a much higher quality. To say it really brightens the atmosphere would be an understatement: the diffuse light you receive from the sun along with the indirect shadows dramatically transform the game’s appearance – and always for the better.

RT reflections are also part of the package, significantly changing the look of reflections on surfaces like windows, transforming them from low-quality raster versions into per-pixel RT upgrades. However, unlike other games with a physically-based pipeline, these RT reflections do not uniformly apply to all materials depending on the angle. Instead, RT reflections apply to specific materials within the game that are marked as either ‘somewhat shiny’ or ‘fully shiny’ in the original. Nonetheless, at maximum settings, the BVH structure for RT (the geometry against which rays are traced) is far more intricate than the console versions – meaning that even though the method is selective, it is also much more detailed than what Xbox or PS5 can provide.

In fact, the RT global illumination solution is so comprehensive that it cannot simply be seen as a superficial add-on to the original game. A considerable amount of care and development effort has gone into it, which undoubtedly seems like quite a deal for a free update for just one version of an older game. In reality, based on our analysis of GTA 6’s first trailer, there is substantial evidence here to suggest that this technology may likely be backported from the forthcoming Rockstar title to GTA 5 on PC. So, we might indeed be getting an early glimpse of the lighting abilities showcased in GTA 6 concerning both the features we can expect and the performance levels we can anticipate.

Let me substantiate my reasoning here with a selection of points. Typically, when an older game gets updated to this degree with some form of ray tracing limited to just a subset of the platforms that can run it, developers often restrict ray tracing somewhat. For example, in Dead Light 2, the RTGI only works from sunlight but not from other light sources. Similarly, in the The Witcher 3’s recent-gen update, RTGI does not operate on a per-pixel basis and is instead applied roughly across the world using probes, leading to apparent artifacts as a result.

This is not the case here – it is far more detailed. First off, it applies to all light sources, not just the sun. This is not limited to static lights, but even dynamic lights, like those from vehicles. Achieving diffuse light from any random light source in the world to work consistently and coherently is a challenging task requiring a lot of work, but it is clear that Rockstar has put in the effort. The RTGI is indeed per-pixel as well, demonstrating very finely detailed shadows and light reflection without any of the artifacts seen in less expensive or simpler implementations. And based on what we have seen in GTA 6’s initial trailer, a per-pixel RTGI implementation is also present, which works exceptionally well with emissive materials – surfaces in the game meant to emit light.

As you can see in the video above, I put this to the test with some challenging examples – and it performs remarkably well. In summary, it is encouraging from the GTA 6 trailer that RTGI is present, with a comparable level of fidelity to the same technology demonstrated in the newly RT-enhanced GTA 5 for PC.