Runtime Errors - Health & EXP hud meters.

ID:142306
 
Jun 27 2008, 4:40 am
Code:
mob/Login()
    if(prob(50))
        src.loc = locate(9,9,1)
    else
        src.loc = locate(27,9,1)
    src << browse(loginmessage)
    src.client.screen += new/obj/hudMeters/health_01
    src.client.screen += new/obj/hudMeters/health_02
    src.client.screen += new/obj/exphudMeters/exp_01
    src.client.screen += new/obj/exphudMeters/exp_02
    src.updateHealth()
    src.updateEXP()

mob
    proc
        updateHealth()
            var/percent=round(src.health/src.mhealth*100,10)
            if(percent>100) percent=100
            if(percent<0) percent=0
            for(var/obj/hudMeters/o in src.client.screen)
                o.icon_state=num2text(percent)
            spawn(10) src.updateHealth()
mob
    proc
        updateEXP()
            var/percent=round(src.exp/src.mexp*100,10)
            if(percent>100) percent=100
            if(percent<0) percent=0
            for(var/obj/exphudMeters/o in src.client.screen)
                o.icon_state=num2text(percent)
            spawn(10) src.updateEXP()


obj
    hudMeters
        health_01
            icon='meter_01.dmi'
            icon_state="0"
            New(client/c)
                screen_loc="1,1"
                c.screen+=src
        health_02
            icon='meter_02.dmi'
            icon_state="0"
            New(client/c)
                screen_loc="2,1"
                c.screen+=src
    exphudMeters
        exp_01
            icon='emeters_01.dmi'
            icon_state="0"
            New(client/c)
                screen_loc="1,2"
                c.screen+=src
        exp_02
            icon='emeters_02.dmi'
            icon_state="0"
            New(client/c)
                screen_loc="2,2"
                c.screen+=src


Problem description:

proc name: updateHealth (/mob/proc/updateHealth)
runtime error: Cannot read null.screen
proc name: updateEXP (/mob/proc/updateEXP)
runtime error: Cannot read null.screen
proc name: New (/obj/hudMeters/health_01/New)
runtime error: Cannot read null.screen
proc name: New (/obj/hudMeters/health_02/New)
runtime error: Cannot read null.screen
proc name: New (/obj/exphudMeters/exp_01/New)
runtime error: Cannot read null.screen
proc name: New (/obj/exphudMeters/exp_02/New)
BYOND Warning: further proc crash messages are being suppressed to prevent overload...


This has only happened when the client clicked load to load his/her character. There was much more than this, but it was the same runtime error for each person, so I just narrowed it down to the one of each.
Jun 27 2008, 4:58 am
Use Client/New() to add things to the screen instead of Login(), i'm fairly sure you'll see better restults.

Also, make sure you have #define DEBUG in your code so you can pinpoint EXACTLY what line the error is comming from.
Jun 27 2008, 4:59 am
When you load a character, your client logs out on the current mob and logs in to the saved mob.

The previous mob continuously calls updateHealth() and updateEXP(). Remember that you logged out from that mob? That means its client is null. (Like what the runtime error says)
Jun 27 2008, 7:06 am
Howey wrote:
Code:
> mob/Login()
>   if(prob(50))
>       src.loc = locate(9,9,1)
>   else
>       src.loc = locate(27,9,1)
>   src << browse(loginmessage)
>   src.client.screen += new/obj/hudMeters/health_01
>   src.client.screen += new/obj/hudMeters/health_02
>   src.client.screen += new/obj/exphudMeters/exp_01
>   src.client.screen += new/obj/exphudMeters/exp_02
>   src.updateHealth()
>   src.updateEXP()
>


Your issue is here, you're not creating the objects how the New() function you defined expects them to be created. You need to do:

new/obj/hudMeters/health_01(src.client)

And whatnot instead, because inside of New() you're adding to the screen already and you're telling it that it needs a client passed as the argument. Without that argument you're trying to add the object to nothing's screen.