Details The player view camera is not in sync with the rest of the game, causing visible stuttering when walking or moving the camera when the FPS aren't exactly matching the maximum refresh rate of the screen. Explanation: At startup, the game syncs the frequency at which the camera follows the player's movement to the desktop refresh rate, causing jittery camera movement when looking around or walking. This issue is most noticeable when FPS fall below the refresh rate or when using Variable Refresh Rate. If you stay still and observe an object moving, it will appear smooth, showing the issue is only with the camera movement. The menu's smoothness appears correctly too (no stutter). The stutter is only when the camera moves while following the player. Easy way to reproduce: For example, when opening the game with a refresh rate of 24Hz and then switching to a higher refresh rate while the game is open, the game's camera will still update at 24 FPS, as it was the maximum refresh rate at the moment and the camera movement will be desynced, but the rest of the game will look correctly. (It seems that stutter can still happen even at matching refresh rates due to normal frame time variation). How I realized: The stuttering was most noticeable with Variable Refresh Rate (VRR) monitors, but it happens in fixed refresh rate too. With VRR: It's possible to see a constant stuttering pattern when moving the camera around/walking and the game's FPS aren't equal or evenly divisible to the refresh rate selected when the game was launched. Fixed refresh rate, and VSync Off: When the frame rate drops below the refresh rate, there will be screen tearing as expected, but there will be stutter behind the screen tearing too (which shouldn't happen as the screen tearing is how the frames that are out of sync are shown in this case, so it shouldn't happen in both ways at the same time.) (This was due to the fact that the camera still updated at 60 FPS, so there was a mismatch with the game's frame rate, and that's what caused the visible stutter). For example: With 55 fps in-game and 55hz reported by the monitor, but with 60hz selected in windows when launching the game, there will be a frame rate mismatch between the camera movement and the game presentation, similar to when you watch a 55 fps video on a 60hz monitor. Steps to reproduce: Select a lower refresh rate to make it easier to see (e.g. 24 Hz). Launch the game. Once already in a world, switch to a higher refresh rate (e.g. 120 Hz). Look how the game's camera still moving at 24 fps despite the rest of the game updating at 120 fps (easier to see while watching an object that moves constantly). What's expected: The game camera follows the player movement smoothly. What happens: The game camera movement is stuttery, only updating its position 24 times every second. Attachments I attached 2 videos demonstrating the behavior of the issue. Launched_at_120_FPS : This video shows how the camera smoothness behaves when the game was launched with a 144 Hz refresh rate selected. (camera movement is consistent, smooth and matches the game's fps). Launched_at_24_FPS : This video shows how the camera smoothness behaves when the game was launched with a 24 Hz refresh rate selected. movement is inconsistent, jittery and doesn't match the game's fps). (It's easier to notice the difference in the videos with a high refresh rate monitor). Make reference to the difference in smoothness of the camera when walking from left to right, and the same smoothness of the pendulum on both videos.
