4 ms·
> Like in a video game, the world moves at the same rate regardless of the frame rate If only this were true. There are plenty of games where the frame rate is
by andrewstuart2 8y ago
> Like in a video game, the world moves at the same rate regardless of the frame rate
If only this were true. There are plenty of games where the frame rate is capped at 60hz because the physics engine is coupled to it. If you force a framerate increase via .ini tweaks or something, you get really weird physics. I think Skyrim had this problem. Also, there are examples of where changing the network tick rate [1] can affect the physics engines.
[1] https://www.youtube.com/watch?v=sB5u96Vgyks https://www.youtube.com/watch?v=sB5u96Vgyks
- saagarjha 8y agoWhat happens if your computer can't support a 60 Hz frame rate?
- deleted 8y ago[deleted]
- LeoNatan25 8y agoThe games slow down. Until recently, most Japanese games were tightly tied to 30hz or 60hz logic, and would speed up or slow down if forced (willfully or not) to run at different frequency. This is not strictly a Japanese games phenomenon, but I've seen it mostly in PC ports of Japanese developed games for consoles. To me, that's bad software design. 40 years ago, developers used to sync their logic to the refresh cycles of the target machine's display. That's amazing, but also something that should not happen in 2018 (or 2010 or 1998).
- peterburkimsher 8y agoIsn't that the reason for the Turbo button? For the younglings: it was a physical button to underclock the CPU on old PCs. https://en.m.wikipedia.org/wiki/Turbo_button https://en.m.wikipedia.org/wiki/Turbo_button
- LeoNatan25 8y agoYes, but the turbo button is and should remain a relic of the past, rather than a cornerstone of modern gaming design.
- yoklov 8y agoEh, it’s extremely difficult to write a physics engine that behaves predictably with variable timesteps. Likely impossible at the extremes.
- fnordsensei 8y agoMy ignorance on this subject is a vast abyss, but reality seems to work OK with this, because "subjective" and "objective" time can be decoupled. The world doesn't really care if your video camera takes a snapshot every 1/30th or 1/60th of a second, it'll keep doing whatever it is doing at its own pace. Can't a virtual world be built with the same principles?
- cuban-frisbee 8y agoThey can and they are. Take for example Forza Motorsport, the physics engine, i.e. How the cars react to different road conditions updates at 360 hz while the graphics updates at 60 hz.
- vbezhenar 8y agoMay be real world is simulated with 5.39e44 fps, so you won't feel the difference between 30 fps or 60 fps camera. You can't simulate virtual world with similar performance yet.
- GolDDranks 8y agoThe framerate of the physics simulation can be decoupled from the frame rate of the rendering loop. For example, you can aim for a 30fps steady timestep simulation and a vsync-capped rendering. you can then use interpolation methods for quick-and-dirty calculation to smooth the movement to match the rendering timestep.
- IshKebab 8y agoNo it isn't. You might need to set a minimum time step to avoid instability but a variable time step is trivial. The only place it might cause issues is if you need it to be deterministic, e.g. for multiplayer.
- jdmnd 8y agoI found this[0] discussion on Jonathon Blow's youtube channel about game physics/framerate dependence. It certainly seems to more than simply a problem of software architecture as some commenters appear to suggesting here. [0] https://www.youtube.com/watch?v=fdAOPHgW7qM https://www.youtube.com/watch?v=fdAOPHgW7qM