LAB NOTES
Will We Ever Get Total Ray Tracing?
The math says no
ZAK STOREY, EDITOR-IN-CHIEF
© CD PROJEKT RED
I’VE BEEN HAVING fun with ray tracing in World of Warcraft and Cyberpunk 2077. It’s pretty cool, but it’s not perfect—most importantly, in what it tries to mimic: light.
A quick tl;dr on ray tracing. Nvidia has dedicated hardware on its current-gen RTX cards that simulates how light works by using “rays” to predict certain variables. It does this by bouncing an individual particle or ray off the geometries and materials in the game scene to try to get a better understanding of how shadows are formed and light reacts with those materials. That gives more realistic shadows, reflections, and refractions. It’s the same technique used in a lot of CGI in Hollywood blockbusters. The difference is that in GPUs we only use a comparably small number of rays per scene, as it takes an incredible amount of processing power to achieve this in real time, so a lot of the gaps are plugged with clever use of both traditional rasterization and ray tracing.