Exp Hit giving a weird runtime error......

ID:262157
 
Nov 23 2004, 3:35 pm
For some reason, people tend to complain that they can't hit anything in my game. I looked into this more closely and found this out as a runtime error:
runtime error: Cannot read null.exphit proc name: Attack (/mob/verb/Attack) source file: Attack And Equip System.dm,110 usr: \[Owner... (/mob/players/Knight) src: \[Owner... (/mob/players/Knight) call stack: \[Owner... (/mob/players/Knight): Attack()

This runtime error prevents players to actually hit their target, but the icon still does the attack animation. Here's my Attack verb that covers line 110. (W/O the attack animation code)
mob
    verb
        Attack()
            if(usr.attacking == 0)
                var/obj/K = new/obj/Weapons 
                usr.attacking = 1
                K.dir = usr.dir
                K.loc = usr.loc
                step(K, dir)
                var/turf/X = K.loc
                spawn(3)
                    del(K)
                for(var/mob/M as mob in X) 
                    if(M == src)
                        if(M.pvp == 0)
                            usr << "<font size=1>They are not PK!"
                            return
                        else
                            continue
                    var/damage = rand(1,usr.attack-10+usr.attackadd-M.defense+10+M.defadd)
                    if(damage <= 0)
                        damage = 1
                    M.killlist += usr.name
                    if(prob(70))
                        var/num = damage
                        s_damage(M, num, "red")
                        usr.exp += M.exphit
                        levelup()
                        M.health -= damage
                        if(M.health <= 0)
                            levelup()
                            Death(M)
                    if(prob(10))
                        var/num = damage*2
                        s_damage(M, num, "red")
                        usr.exp += M.exphit  // <--- Right here is line 110
                        levelup()
                        M.health -= damage*2
                        if(M.health <= 0)
                            levelup()
                            Death(M)
                    else
                sleep(7)
                usr.attacking = 0


It's kinda hard to reproduce the problem kind of, as the production of the runtime error is pretty random. Anyone have any fixes/suggestions?
Nov 23 2004, 3:59 pm
According to that runtime, Exphit is null, and it can't subtract a null value, so your going to have to set exphit to something. (Thats what it seems like.)
Nov 23 2004, 4:01 pm
Mega fart cannon wrote:
For some reason, people tend to complain that they can't hit anything in my game. I looked into this more closely and found this out as a runtime error:
<code> > runtime error: Cannot read null.exphit > proc name: Attack (/mob/verb/Attack) > source file: Attack And Equip System.dm,110 > usr: \[Owner... (/mob/players/Knight) > src: \[Owner... (/mob/players/Knight) > call stack: > \[Owner... (/mob/players/Knight): Attack() > </CODE>

It's kinda hard to reproduce the problem kind of, as the production of the runtime error is pretty random. Anyone have any fixes/suggestions?

The mob they're attacking is probably already dead. if(prob(70)) succeeded, and the enemy mob was attacked. The enemy mob died. After that if(prob(10)) also succeded. Unfortunately, M is already dead and gone.
Nov 23 2004, 4:04 pm
In response to Lenox
Lenox wrote:
According to that runtime, Exphit is null, and it can't subtract a null value, so your going to have to set exphit to something. (Thats what it seems like.)

<code> runtime error: Cannot read null.exphit </CODE>

The runtime is saying that it can't read null.exphit
The object that is being accessed is null. In this case, it's M, a mob.
Nov 23 2004, 4:06 pm
In response to Jon88
Jon88 wrote:
The mob they're attacking is probably already dead. if(prob(70)) succeeded, and the enemy mob was attacked. The enemy mob died. After that if(prob(10)) also succeded. Unfortunately, M is already dead and gone.

To fix this, you're going to need to add an if expression check to make sure that M is still alive.
Nov 23 2004, 4:15 pm
In response to Wizkidd0123
Do I have to make an if expression or can for() work also?
Nov 23 2004, 4:33 pm
In response to Mega fart cannon
Mega fart cannon wrote:
Do I have to make an if expression or can for() work also?

You're going to need an if().
for(var/A in MyList) statement
, as you're using it, means that it will loop through everything in MyList, and everytime it finds an element which matches A in that list, it will execute statement. So,
for(mob/M in world) M << "You are a mob."

means that for evrey single mob in the world, it will tell each mob: "You are a mob.".
Nov 23 2004, 4:38 pm
In response to Wizkidd0123
Ah. It's fixed now. Thanks for all your help!
Nov 24 2004, 9:08 pm
You should take another look at your Death() proc and how it's called, because right now you're doing it backwards. Death() should always be the responsibility of the mob that dies, and it should be sent the killer as an argument. Right now you've got src as the killer and the argument (M) as the victim. A correct DeathCheck() proc looks like this:
mob/proc/DeathCheck(mob/killer)

Lummox JR