Simple scene drops FPS to 58/59 and it shows a lot [3.5.1 stable / GLESS 3]

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Simple scene drops FPS to 58/59 and it shows a lot [3.5.1 stable / GLESS 3]

dandorf

I'm doing a test project and on a simple screen, without enemies, just a tilemap and a character moving with a 2D camera that follows me, the game drops every "x" seconds at 58 or 59 FPS and it's very noticeable because it jerks. ..
It's very annoying and I don't know how to fix it.

I am moving the character with _physics_process and move_and_slide().

In the debugger, Monitors and Profiler tab there is nothing that is excessively overloading the game...

Any ideas?

cybereality

What kind of computer are you running and how complex is the game?

I have a tilemap demo with just a block texture and I can get around 10,000 FPS.

dandorf

cybereality

It is a very simple game.

My PC has the following characteristics:

SSD hard drive and 64 bits OS.

Anyway, the same thing happens to me on my Android phone. I don't think it's a PC problem.

I put a test video of the game and you will see how it jerks... because the FPS drops from 60 to 58/59 from time to time (I have seen it in the debugger)

https://www.youtube.com/watch?v=i1NTetyYbEo

in the second 4 approx of the video you can see what I comment

Pixophir

dandorf ... from 60 to 58/59 ..

That's insignificant. From 60 to 59 could just be a rounding error.

dandorf

Pixophir That's what I thought, that it would be something insignificant, but it is too noticeable in the game... because it jerks every time it drops 1 or 2 FPS.

cybereality

You can test with V-Sync off, but the FPS is never going to be exactly one number. It will fluctuate and that is normal.

dandorf

Without V-Sync it has very high FPS (700 approx) but it still jerks.

I have verified that with the fixed camera this is much less noticeable. But I'm interested in the camera follow you all the time.

Megalomaniak

dandorf Without V-Sync it has very high FPS (700 approx) but it still jerks.

This is why for debugging purposes graphing the frametime is better. Also see what is going on in process and physics on the low rate/slow frames if you can. It might be something on the cpu side and not gpu that is bottlenecking/taking long on those frames.

Pixophir

Then it is most probably something different from the mere frame rate, or even the flow of the game. Maybe a virus checker or some such ... but I can just guess without more information.

cybereality

Could be something with loading files. DIsk reads can cause hiccups. Probably not GPU related if you get 700 FPS without VSync.

Object creation or deletion can also cause hiccups.

dandorf

The game so far is super simple, because I'm testing the main mechanics before starting game development.

I put a couple of images of the debugging of the game to see if it helps.

I ask out of ignorance...

Could the problem be due to the constant movement of the camera follow the player? because if I leave camera static those unwanted stutters don't happen

cybereality

No, the camera would not cause that. But a moving camera can cause things to happen, such as objects appearing or disappearing, which could have an effect on the performance.

Honestly, the 59 FPS thing is not the problem. Even AAA games will hover around 58 - 62 FPS because it is not perfect, every frame is doing something different so it's not possible for it to be exactly the same.

The issue is probably with your logic being framerate dependent. If you use the delta parameter (the time of the last frame) and make sure all movement code is based on delta, then it doesn't matter the frame rate.

You could even have a game drop from 60 FPS to 45 FPS to 30 FPS and then back to 60 FPS and there will be no slow down. Granted it won't look as smooth, but there will be no difference in the speed of objects or hiccups.

So you might want to double check and make sure you are using delta and timing correctly, having the right things in physics process and/or process and updating correctly.

http://kidscancode.org/godot_recipes/4.x/basics/understanding_delta/

dandorf

I'm using move_and_slide() in _physics_process and in that case I think it's not necessary to use _delta (I'm not actually using it).

So surely the problem is then in the calculation of the speed of the character or something similar.

Keep investigating!!!

Thanks so much for the help

Pixophir

I don't think that deltatime has to do with what you describe, but without code and maybe the scene that's just adding to the guess work. Here are some hints for better help with problems: https://docs.godotengine.org/en/latest/getting_started/introduction/learning_new_features.html?highlight=community#learning-with-the-community.

dandorf I'm using move_and_slide() in _physics_process and in that case I think it's not necessary to use _delta (I'm not actually using it).

For being independent from frame time, delta must be used to calculate the velocity of an object in _process or _physics_process. move_and_slide() then calculates the outcome of the object's position based on velocity.

https://docs.godotengine.org/en/latest/classes/class_characterbody3d.html?highlight=move_and_slide#class-characterbody3d-method-move-and-slide

But the differences here are so small that I doubt there is any visible effect, and I think what we see in the video is not in the engine or in the game, but some other process is causing it.

dandorf

I have created a new project to simplify as much as possible and see where the problem is.

I share what I have:

Project config:

World scene:

Player scene:

Player gd:

The tiles and the character are 64x64 px.
I don't know what more info I can give you, I hope you can help me solve it.

It's super simple, very few resources and very little code...
Well, it keeps giving those annoying "jerking" when the FPS drops.

I don't understand, I'm desperate now.
Maybe I'm making some noob mistake (what I am, I'm just starting at this), but I can't see it

Thank you all very much for the help!

cybereality

The code looks fine to me. Maybe speed should be a float, but I think it auto converts.

var speed = 450.0

What operating system are you using and what monitor resolution and refresh rate? It may be a system/OS issue and not Godot.

Also, that bounce code won't work. You should probably either check for collision or use an Area2D or ray cast to see if it touched the wall. You might want to remove that code.

Megalomaniak

Try changing line number 6 to:
func _process(_delta):

See if that changes it. I don't really see any reason that particular code has to be executing in physics step.

cybereality

It does because they are calling move_and_slide and that calls into the physics engine.

I have found that using process is smoother, however can cause issues when the frame rate and physics step are out of sync.

So yes, that will likely fix the stutter, but may cause other issues down the road depending on how they use the physics engine.

Megalomaniak

cybereality Then their best way forwards might be to increase the physics fps perhaps.