For the vast majority of scenes in games, the best balance of performance and quality is precomputed visibility, lighting and reflections in static levels with hand-made model LoDs. The old Quake/Half-Life bsp/vis/rad combo. This is unwieldy for large streaming levels (e.g. open world games) and breaks down completely for highly dynamic scenes. You wouldn't want to build Minecraft in Source Engine[0].
However, that's not what's driving raytracing.
The vast majority of game development is "content pipeline" - i.e. churning out lots of stuff - and engine and graphics tech is built around removing roadblocks to that content pipeline, rather than presenting the graphics card with an efficient set of draw commands. e.g. LoDs demand artists spend extra time building the same model multiple times; precomputed lighting demands the level designer wait longer between iterations. That goes against the content pipeline.
Raytracing is Nvidia promising game and engine developers that they can just forget about lighting and delegate that entirely to the GPU at run time, at the cost of running like garbage on anything that isn't Nvidia. It's entirely impractical[1] to fully raytrace a game at runtime, but that doesn't matter if people are paying $$$ for roided out space heater graphics cards just for slightly nicer lighting.
[0] That one scene in The Stanley Parable notwithstanding
[1] Unless you happen to have a game that takes place entirely in a hall of mirrors
Yep. I worked on the engine of a PS3/360 AAA game long ago. We spent a long of time building a pipeline for precomputed lighting. But, in the end the game was 95% fully dynamically lit.
For the artists, being able to wiggle lights around all over in real time was an immeasurable productivity boost over even just 10s of seconds between baked lighting iterations. They had a selection of options at their fingertips and used dynamic lighting almost all the time.
But, that came with a lot of restrictions and limitations that make the game look dated by today’s standards.
I get the pitch that it is easier for the artists to design scenes with ray-tracing cards. But I don’t really see why we users need to buy them. Couldn’t the games be created on those fancy cards, and then bake the lighting right before going to retail?
(I mean, for games that are mostly static. I can definitely see why some games might want to be raytraced because they want some dynamic stuff, but that isn’t every game).
The player can often have a light, and is usually pretty dynamic.
One of the effects I really like is bounce lighting. Especially with proper color. If I point my flashlight at a red wall, it should bathe the room in red light. Can be especially used for great effect in horror games.
I was playing Tokyo Xtreme Racer with ray tracing, and the car's headlights are light sources too (especially when you flash a rival to start a race). My red car will also bounce lighting on the walls in tunnels to make things red.
It doesn't even have to be super dynamic either, I can't even think of a game that has opening a door to the outside sun to change the lighting in a room with indirect lighting (without ray tracing it). Something I do every day in real life. It would be possible to bake that too, assuming your door only has 2 positions.
However, that's not what's driving raytracing.
The vast majority of game development is "content pipeline" - i.e. churning out lots of stuff - and engine and graphics tech is built around removing roadblocks to that content pipeline, rather than presenting the graphics card with an efficient set of draw commands. e.g. LoDs demand artists spend extra time building the same model multiple times; precomputed lighting demands the level designer wait longer between iterations. That goes against the content pipeline.
Raytracing is Nvidia promising game and engine developers that they can just forget about lighting and delegate that entirely to the GPU at run time, at the cost of running like garbage on anything that isn't Nvidia. It's entirely impractical[1] to fully raytrace a game at runtime, but that doesn't matter if people are paying $$$ for roided out space heater graphics cards just for slightly nicer lighting.
[0] That one scene in The Stanley Parable notwithstanding
[1] Unless you happen to have a game that takes place entirely in a hall of mirrors