Sleeping in a while loop, then activating the loop again before the sleep ends causes double loops.

ID:2187896
 
Dec 18 2016, 10:13 am
(See the best response by Ter13.)
Code:
mob
    proc
        moveRun(i)
            if(i)
                if(stamina > 5)
                    state = STATE_RUN
                    move_speed *= speed
                    accel += 2
                    world << output("Running.", "chat")
            else if(!i)
                if(state == STATE_RUN)
                    state = STATE_NULL
                    move_speed /= speed
                    accel -= 2
            while(state == STATE_RUN)
                lastRun = world.time
                staminaChange(0, 5)
                world << output("[usr] has [stamina] stamina. Stamina percentage is [round(stamina/maxStamina * 100)].","chat")
                sleep(20)


Problem description:
If I were to run, stop running, then start before the sleep(20) ends - it will create two instances of the loop. How would I resolve this?



Dec 18 2016, 10:30 am
You could add an if that only does what u wanna do if last run +20 is less than or equal to world.time
Dec 18 2016, 11:03 am
Best response
 
mob
    var/tmp
        state = STATE_NULL
        state_time = 0
    proc
        moveRun(i)
            if(i&&state!=STATE_RUN)
                var/time = world.time

                state = STATE_RUN
                state_time = time
                move_speed *= speed
                accel += 2
                world << output("Running.","chat")

                var/ntime = time
                while(state==STATE_RUN&&state_time==time&&stamina>0)
                    if(world.time>=ntime) //only do this every 2 seconds.
                        staminaChange(0,5)
                        world << output("[usr] has [stamina] stamina. Stamina percentage is [round(stamina/maxStamina * 100)].","chat")
                        ntime = world.time+20
                    sleep(world.tick_lag) //repeat every tick so the loop will end immediately on state change
                if(state==STATE_RUN&&state_time==time) //this only happens when the user runs out of stamina
                    state = STATE_NULL
                    state_time = world.time
                move_speed /= speed
                accel -= 2
            else if(!i&&state==STATE_RUN)
                state = STATE_NULL
                state_time = world.time


The reason you are getting two loops is because they aren't gated properly.

With state machines, I like to not only track the state, but also the time that the state was last changed. This makes it so that state loops don't tend to double-trigger unless you enter, exit, and then enter the same state in the same frame, which shouldn't be allowed in the first place.

With state loops, I also prefer not to sleep for any period of time longer than a tick. sleeping for longer than one tick can mean that iterations can overlap if the state machine transitions states multiple times during a longer sleep.
Dec 18 2016, 11:55 am
In response to Ter13
Thanks for your help!