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How Much Can Real Time Ray Tracing Really Impact A Game?


Ray tracing is all the rage these days thanks to the recent RTX announcement from NVIDIA, but it's not something that people haven't already been chasing after. If you're looking for a deep discussion of what Ray tracing is or how it works you're not going to find it here, but from a high level it's using actual light sources and paths rather than glowing fake light that just illuminates areas in games.

A while back a friend clued me in on a project that enabled pathtracing in quake 2, not having time to really dig in back then I shelved it to later return for fun.  But, that changed recently as I was researching ray tracing from a programmer/developer side of things when I stumbled back across it and decided to dig in a bit. You can find more over on the site that details the Quake 2 Realtime GPU Pathtracing notes.   This article is not to figure out how to explain how it's done, but rather to show the difference from before and after it's applied.  This is honestly best left seen in action and is why the video below is the focal point of this.

I also felt it was important to have a side-by-side comparative point so we made sure to include this juxtaposition to really show the impact of the change.  It also really exaggerates one of the biggest hurdles of real time tracing, noise.  The noise that you're seeing is, in it's basic form, where the light is dispersing from and just simply can't be drawn faster.  It's similar to digital noise in the way it appears, but is actually worse as you introduce more and more light sources as it becomes more difficult to render in real time.

Our editor Usman took things a step further and actually combined the image to show what it would, or could, look like if this was utilizing NVIDIA's hybrid rendering method used in their new RTX suite.  The result was pretty impressive on what a combination of light tracing and normal game illumination could achieve.

So, it's really neat to see just what an impact this made on a 20 year of game it's going to be just as interesting to see what it does in the future.  I'll be spending a bit more time in the future looking at real time ray tracing from perspectives other than NVIDIA as well, because that does exist as quiet as they've been lately.