This week, after hearing Sony confirm, and then describe, the next PlayStation under development, you may be wondering what exactly “ray tracing” is and why it’s such a differentiator when it comes to high performance video game hardware. Here is a surprisingly watchable technical demonstration from Digital Foundry — using Minecraft of all things — to point out its applications — like your username casting a shadow.
Minecraft, using the mod Sonic Ether’s Unbelievable Shadows, makes for a surprisingly good test space. It’s not just because Digital Foundry’s Alex Battaglia and John Linneman can build rooms that call attention to concepts like “specularity,” and “bounce lighting” and “differentiated reflective surfaces.” Its because the voxelized world is optimal for the real-time demands of ray tracing.
“To have the entire world always be known [by the CPU] as being made of blocks is what mes this so performant,” Battaglia explains.
“Because these objects are non-moving and in a binary, present-or-deleted situation, that makes the calculations easier,” Linneman adds.
The rooms they’ve built show off not just those highly coveted godrays of sunshine, and indirect lighting, but also how a room can be indirectly lit off multiple reflections of a light source, and how colored surfaces’ reflections, will also mix and change when they bounce onto another colored surface. It is a highly technical discussion, of course, but the visuals are always there to fall back on, to illustrate what kind of a load the hardware has to carry to pull it off.
“It honestly just looks like an architectural rendering,” Battaglia says at one point.
“This is how light functions in the real world,” Linneman says simply. “Many games have a way of faking this effect, but this is generated in real time.”
Battaglia’s hardware for this technical demonstration is more powerful than an Xbox One X, and yet with this path-tracing* mod installed, it’s running at 720p locked to 30 frames per second — if that gives you a sense of how much this kind of rendering asks. Or as one joker put it in the YouTube comments: “2007: But can it run Crysis? 2019: But can it run Minecraft? Oh how the times have changed.”