Visual analysis
Sometimes people say that today’s games don’t measure up to the old ones and don’t offer much besides visuals. But what if modern visuals could be added to classic games that are even twenty years old? NVIDIA’s RTX Remix technology (or software) is supposed to do just that, making it relatively easy to add better graphics to even very old games using a mod – including raytracing effects and things like DLSS or DLAA. Let’s see how it works.
Visual analysis
Original Portal vs. Portal with RTX
The very first scene from Portal using shows what a difference remixing to ray tracing graphics makes in an old game, and we’re not just talking about the visual quality of the detail, but rather the overall different character of the scene that path tracing/ray tracing creates. On the left you have the original Portal, on the right you have Portal with RTX (native resolution, without upscaling), with ray tracing. The comparison is made with NVIDIA’s ICAT tool.
Scene 1
The fundamental problem with traditional graphics, at least in these older games, is how the limited lighting simulation flattens the scene. Basically, there’s no sharp light, no darkness, and no sharp shadows. The darkest part under the cubicle is kind of grayed out and bright due to the small dynamic range. On the other hand, the light forms a kind of visible “ether” spreading from the lamp, although in the practical world it would not look like that. Because this illumination is spilt over a large part of the scene without contrast, the impression that the light is really bright is actully lost.
The result is more of a fog or haze. This fog, reminiscent of a view of a distant horizon in natural exterior, gives the game an unnatural look overall, but one that you wouldn’t find too noticeable if you were used to such games back in those days. But it comes out very clearly when you compare the image to the remixed version.
In Portal with RTX, the whole scene is free of this haze, and you can clearly see into the glassed-in area in the foreground, and the office section behind the glass in the back at the top. In a space with artificial lighting of this nature, the environment should definitely look more like this. The illuminating light effect and reflections of the open portal, which are missing in the original, are nice too.
Scene 2
That difference between the milky character of the light (left) and the contrasted raytracing lighting (right) is also present in the next scene. The raytracing technology adds portal reflections to the glass that are absent in the original.
Also note the difference in material on the floor and walls. This is texture replacement with RTX Remix in practice, it’s not just upscaled or using a higher resolution, instead the texture was replaced with a different graphical asset based on some stylistic choice of the modders. Again, we see the effect where the glass is somewhat bluish in the original game, adding a haze that the remixed version doesn’t carry over (one wonders to what extent this was the intention in the original). On the other hand, the new technology adds the ability for the glass to distort the image based on its material nature – note how the horizontal stripes on the glass break the shape of the portal behind it with light refraction effects.
Scene 3
The third scene is again transformed due to the texture replacement, but especially by the lighting, where the original (left) is perhaps quite overbrightened, although it is up to question whether the light in the remixed version (right) isn’t a bit too dim in turn. The strange cast shadows stretching horizontally across the walls and floor have disappeared in the raytraced version, but instead there are now properly cast real shadows from the cage in the corner and the camera or sensor on the wall. The latter unnaturally stands out against the light wall in the original version.
But raytracing makes a big difference on objects. The original doesn’t use illumination on the inside of the cubes, and the red light on the mechanism that drops them is also pretty unnatural. The biggest difference though is the series of lights on the ground, which in the original look like they’re painted on, whereas in the remixed ray-traced version you believe they’re glowing.
In the corridor passage you can notice the differently designed lighting at the end of it. This is again one of the things where modifications made with RTX Remix can make stylistic changes. Old games don’t have lighting that is very complex (much less based on the physical workings of its sources), which mods not only can, but in fact often must address and retouch the lighting design somehow.
Scene 4
In the final screenthos you can see how the presentation of the material changes with ray tracing (right). The original visual (left) couldn’t create the impression of things gleaming that ray tracing simulates quite nicely – see especially the cube-mosaic material on the sides of the foreground passage.
However, the light also reflects diffusely off the floor, which, along with the way the light is cast from a distant bright room, creates a much more natural feel and improves realism. It also allows you to perceive the perspective and distance of the opposite wall better. The original Portal cannot render the light and shadow that is created in a scene in this way.
The original also again suffers from that flattened rendering of light levels in the scene, whereas the remix has a more dynamic composition of light and dim or dark parts.
You can also notice the appearance of the metal pyramids above the passage in the foreground, or the added grilles on the doors (again, replacing the asset instead of just improving it).
Tomb Raider with RTX (Open Lara RTX: Reimagined Realms)
With Portal, we said that the realistic behavior of light and shadow makes a big difference in how natural a scene feels and how immersive it can be. Tomb Raider is probably an even better demonstration of this, as those light levels are even more primitive and flattened in the original. While you won’t lose your orientation in space in Portal, even though the nature of its original visuals already already has a bit of that feel, in old games like Tomb Raider, for example, that effect is already considerable for me.
In the RTX Remix modification, the environment is completely different. Using path tracing to render this game does dramatically change the look of virtually all the scenes, and leads to darkness in a lot of places that has to be dealt with by that flashlight tool we were mentioned in the previous chapters, but the perception of space is much better. You are also more likely to notice various niches, bends or openings that might not have been very noticeable in the original version (it is of course possible that this reduces the difficulty of puzzles where the authors may have relied on this).
The lighting added in front of the character that you see here is the flashlight feature. This is a tool that many mods use to overcome the fact that while the original game had uniform visibility due to technical limitations, the addition of realistic lighting by RTX Remix often causes nothing to be visible in the game environment. However, this also corresponds to how the environment should realistically work. Ideally you would want the flashlight to be held directly by the character, but that would already require modifying the game’s program and is beyond what RTX Remix can do (however, with Open Lara RTX it could probably be done, since it is a rewrite and replacement of the original game code).
Here you can see quite well how working with lighting will give you better grasp of the depth of the scene and improve your orientation. But you’re also more likely to see the various attacking vermin in this game, which you can often notice too late in the original, unless you are familiar with the game.
There’s something very interesting about the RTX Remix mod of Tomb Raider that might not be so visible in the final form, if the author proceeds with major replacement of in-game assets with brand new ones. If you click through our screenshots, you’ll see that the original low-resolution textures are still used, which are more of a kind of pixelized impressionism than a realistic representation of objects and materials. This looks, let’s face it, quite bad in the original game.
But it’s remarkable how much the impression changes when the same thing is rendered with realistic lighting and shadows. The transitions this creates mercifully hide extreme texture imperfections and even extremely angular models (look at how your hands look with the guns drawn, for example), at least in interior and dark scenes. It’s possible that after several hours of playing, one gets used to this and starts to see those imperfections again.
This image shows how incredibly primitive the original game’s environment is from today’s perspective. The shadows and light rendered by ray tracing can help the final look a lot, though. It works better when the scene is dark and there’s a local light source throwing shadows like this.
In strong daylight and outdoors, ray tracing probably wouldn’t salvage the primitive models and textures as much, as is somewhat hinted in the following image (it would help if there were more different objects and shapes in the scene to cast shadows). The original Tomb Raider is a game set in an interior space, though sometimes a view of the outside environment is simulated.
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- Contents
- RTX Remix?
- How to get ray tracing into old games
- Visual analysis
- How we tested
- Gaming performance in Portal with RTX
- Gaming performance in Max Payne (with RTX)
- Gaming performance in Tomb Raider with RTX
- Conclusion
