Kamehameha Death Check Problem

ID:141687
 
Dec 12 2008, 12:27 pm (Edited on Dec 12 2008, 12:49 pm)
Code:
            Bump(atom/M)
                if(isturf(M)) // If whatever the head bumps is a turf..
                    owner.kame = 0 // Allow the owner to fire another beam
                    owner.icon_state = "" // Give them their default icon_state
                    owner.move = 1 // Allow them to move
                    for(var/obj/O in src.Beam) // Checks for objects in the Head's Beam list...
                        del(O) // Deletes any objects found
                    del(src) // Deletes the head
                else if(ismob(M)) // If whatever the head bumps is a mob...
                    view(src.owner) << "[src.owner]'s beam hits [M]!" // For all in the owner's view, gives a message          
                    M:powerlevel-= M:ki
                    usr.DeathCheck(owner,M)
                    owner.kame = 0 // Allows the owner to fire another beam
                    src.owner.icon_state = "" // Sets them to their default icon_state
                    owner.move = 1 // Allows them to move
                    for(var/obj/O in src.Beam) //For all objects in the Head's Beam list...
                        del(O) //Delete any objects found
                    del(src) // Delete the head
                else
                    if(!ismob(M) && !isturf(M) && !isobj(M) && !isarea(M))
                        owner.kame = 0 // Allow the owner to fire another beam
                        owner.icon_state = "" // Give them their default icon_state
                        owner.move = 1 // Allow them to move
                        for(var/obj/O in src.Beam) // Checks for objects in the Head's Beam list...
                            del(O) // Deletes any objects found
                        del(src) // Deletes the head


mob
    proc
        DeathCheck(mob/M)
            if(M.powerlevel<=0&&M.npc)// if the hp's 0 and its a NPC.
                world<<"<font color=red>[src] has killed [M]</font>"/// say theyve killed M
                src.exp+=M.exp
                del(M)///delete the npc frm the world cuz its dead
                src.Level()// call the lvl proc
                return/// stop runtime errors =D
            if(M.powerlevel<=0&&M.client) // if hp 0 and its a client.
                world<<"<font color=red><B>Player Death:[src] has been killed by [M]</B></font>"// same as before
                M.powerlevel=M.powerlevel_max//give them full hp back.
                M.loc=locate(180,18,1)//take them to spawn point, dont DEL them.
                src.exp+=src.powerlevel// give them exp!!
                src.Level()/// call lvl proc


Problem description: My Death Check don't work. When I try to kill a npc on my game it says error and more errors:

runtime error: Cannot execute null.DeathCheck().
proc name: Bump (/obj/Beams/Head/Bump)
usr: 0
src: Head (/obj/Beams/Head)
call stack:
Head (/obj/Beams/Head): Bump(Vegeta (/mob/npc/Vegeta))
Head (/obj/Beams/Head): Move(Sand (183,22,1) (/turf/Sand/Sand), 8)

What is wrong with my code?


Dec 12 2008, 12:37 pm
1. :(colon operator) abuse. 99.9% of the time, use typecasting, it's safer.
else if(ismob(M))
   var/mob/hit=M //hit refers to M.
   //This only works if M is a mob, which it is due to the conditional above.
   //"hit" will have all mob variables, allowing you to access them.


2. usr abuse. usr doesn't exist in the context you're calling DeathCheck() with. usr is extremely unsafe, 98% of the time.


Bottom line: use owner.DeathCheck(M).


I'm not sure where all you new programmers learn about the : operator. Experimentation? Just DO NOT use it. :)
Dec 12 2008, 12:47 pm
In response to Kaiochao
Oh thanks a lot, it worked.
Dec 12 2008, 2:20 pm
In response to Kaiochao
99.9% of the time, use typecasting, it's safer.

If you want to, you can always use it. Tou could create a datum with the variables of built-in datums that aren't meant to be messed with (appearances, for example) and then type cast the whatever as that datum.

appearance
       var
            icon
            icon_state
            list/overlays
            list/underlays
            pixel_x
            pixel_y
            //there are probably more, I don't know all of them

mob/verb/Overlay_icons()
       for(var/X in overlays)
            var/appearance/A = X
            src << A.icon
Dec 12 2008, 2:45 pm
In response to Jeff8500
Indeed.

Jeff8500 programmed:
> appearance
>        var
>             list/overlays
>             list/underlays
>             pixel_x
>             pixel_y
>             //there are probably more, I don't know all of them


You can't actually use those. >_>
>        for(var/X in overlays)
>             var/appearance/A = X
>             src << A.icon
>

And for that I'd just use the 'as' keyword to override the type, you don't actually need a secondary variable. 
for(var/appearance/A as anything in overlays)
Dec 12 2008, 3:08 pm
In response to Kaioken
Ah, I don't use as much. And as for the overlays/underlays and pixel offsets thing, Lummox JR has said that they do have those vars.
Dec 12 2008, 4:08 pm
In response to Jeff8500
Not in accessable form as far as we're concerned, though.