prevent requestAnimationFrame stops

[leandro]

hello

I'm working on a real time game and I am using the requestAnimationFrame API for the animations. The problem is that when I switch browser tab, stops the animation. I understand that is a feature, but it is possible disable it?

[Chris]

This is the whole purpose for using requestAnimationFrame, so... I fear there is no way to prevent that behavior

 

A suggestion:

use RAF only for your rendering output!
You can base your game logics on a javascript timer - that won't stop doing game calculations when you switch away from the tab.

[rich]

What Chris said Use raf for rendering and a setTimeout for game logic. It's not ideal, but it's easy to check the tab visibility state, so you could actually use raf for everything until the tab loses visibility and then start a setTimeout going.

 

Alternatively you could pause the game and keep track of the time it paused, then when it resumes (i.e. they come back to the tab) you take a count of the time and make-up for that lost time in your game logic (i.e. advance that number of steps).

[Hugeen]

RAF is stopped when you switch tab but using the setTimeout is not a good solution either.

 

Because as mentioned in this link: http://stackoverflow.com/questions/6563859/minimum-setinterval-settimeout-delay-on-background-tabs/6563900#6563900

 

Background tabs have setTimeout and setInterval clamped to 1000ms to improve performance

 

You should pause your game to fix this issue :-(

[leandro]

Thank you very much, this helped me a lot. It seems that I will not be able to use timeouts / intervals. I'll try to use WebWorkers

 

 

see you soon

[Chris]

Why are you not able to use timeouts/intervals? They are available on every browser, whilst WebWorkers arent.

Also, afaik, its not possible to replicate a timeout/interval with a webworker...

[leandro]

by the mechanics of the game I can not pause. My game is like Tetris, between two people and in real time. If someone pauses the game, the other player would be complicated. Also there is some playing time probably would pause or would also be very different for the two players.

 

I have no choice to have something running in the background to make constant checks with the server and many other things

[Chris]

Uhm, that would be a setTimeout() or setInterval() ...

[Ezelia]

@leandro I encountered a similar issue with an online game and my solution was :

 1 - keep gamestate on the server (it's an online game right ?)

 2 - when the window lose focus stop the rendering but continue to update gamestate from the server

 3 - when the window get focus again clear the canvas and redraw the whole scene from the current server side gamestate.

 

the solution will maybe need some modifications in your rendering process but it works just fine

[martensms]

As suggested, split your whole game into two different loops. A render loop that only makes the draw calls and an update loop that executes the game logic and is triggered by a setInterval() finally.

 

You also should know that intervals are executed less precisely when the tab is inactive (to save resources), so you might want to calculate an interpolation load indicator that allows you to implement correct game logic, but has not to be something like precise physics simulations.

[narukaioh]

I'm trying to use setInterval() to make a NPC that move randomly.. but I'm not succeeding..

I'm using an engine (canvas engine) for this. (forgive me if my english is very bad.. e-e"..)

 

anyway.. can someone help me? D: