3d rendering in games even today don't (in general) raytrace. While some things are raytraced in games /today/, getting performance is still achieved largely by leveraging the GPU, which in nowhere near as good at raytracing as general rastering. Essentially GPUs make raytracing faster simply because it is ridiculously parallel, and by limiting the kind of features that are supported (vs. general cpu raytracing)
And also "cheating" -- raytracing is ideally "correct", but for a game you don't need to be correct, you just need to be good enough (or rather, you need to be pretty, which isn't necessarily physically correct).
That said based on the content of the article this could be trivially improved with better data structures -- it's just walking a height map, but the article makes no mention of quad or kd trees which are iirc the standard go to for height map traversal.
My comment came from the observation that making sampled tracing of a depth buffer is similar to what (current, rasterizing) game engines do for ambient occlusion.
SSAO is not remotely close to raytracing (as done here). This post is not discussing ambient occlusion, but actual direction shadows.
SSAO doesn't sample a path across the depth buffer (because that wouldn't make any sense at all for shading), or consider light direction. This is very much my recollection from many many years ago, but basically my understanding is, but I recall that it's just a random sample of depth information surrounding a given fragment, and uses the depth of those samples relative to the current fragment as a scaling factor for the ambient contribution to to the final fragment light. The end result isn't even remotely close to correct, but again, correct isn't the same as being looking good enough (or even just looking good - in games you don't have totally control of how a scene may be seen by a player. Incorrect lighting can often be far superior to correct lighting from a gameplay pov.
3d rendering in games even today don't (in general) raytrace. While some things are raytraced in games /today/, getting performance is still achieved largely by leveraging the GPU, which in nowhere near as good at raytracing as general rastering. Essentially GPUs make raytracing faster simply because it is ridiculously parallel, and by limiting the kind of features that are supported (vs. general cpu raytracing)
And also "cheating" -- raytracing is ideally "correct", but for a game you don't need to be correct, you just need to be good enough (or rather, you need to be pretty, which isn't necessarily physically correct).
That said based on the content of the article this could be trivially improved with better data structures -- it's just walking a height map, but the article makes no mention of quad or kd trees which are iirc the standard go to for height map traversal.