Revision as of 23:26, 9 May 2011

Mobile Memory and PC Data Fields

"We all have nightmares to remind ourselves who we really are."
   -- Leonard Shelby, Memento

One of the most prominently lacking features from the original prog specification was

the ability for mobile’s to have a notion of "memory", or the total lack of any internal

state (other than ‘fighting’ or ‘not fighting’).

For example, mobiles could do none of the following:

- Remember which pc’s had been tasked with a quest

- Remember pc’s who have attacked them in the past

- Have a dialogue with a pc, where the mobile remembers what has been said

- Marking a pc to be attacked by all the mobs in a given town or location

- Marking a pc to get lower prices/preferred treatment from various mobs

Given the dearth of these features, we have implemented several different solutions for

these problems.

MOBILE MEMORY

Integer Memory

Firstly, every instance of a mobile has ten integer values associated with it. These

values, or "slots" as they are referred to, are themselves number from 0 to 9. From

within a prog, these values can be set to specific values, incremented, decremented,

and then tested by the mobile to see if they are equal to, not equal to, greater than,

or less than a specific value.

To see why this might be useful, consider a hen, which can be "fed" grain. Every time

the hen is fed, it would increment its "0" slot. If the "0" slot is greater than 10 (it

has been fed ten times), it refuses to eat, being too full. Then, over time (via a rand_prog,

say), the hen gradually becomes less full, until it’s ready to eat again.

The following are the mpcommands and if checks associated with mobile integer memory:

mpvalueup

mpvaluedown

mpvalueset

mpvaluerand

if mobvalue(<slot #>)

In addition to these, the value of a slot can be referenced by a variable, given by $0, $1, ... $9,

where the number corresponds to the given slot number.

Thus, if $0 had a value of "3", and $0 appeared in a prog, $0 would be interpreted as "3" wherever

it occurred. [Note: For technical reasons, the $# variables can never appear on the left hand

side of any if check (i.e., before the operator)].

Character Memory

After implementing integer memory for mobiles, we discovered that while useful, it was not yet

complete enough to allow for things we had planned. So, mobiles were given character memory,

in the form of focus fields.

Essentially, the focus fields allow the mobile to store PC information. Mobiles have two focus

fields, though they may have more in the future. Mobiles store their focus in the $f variable.

$f0 references the first focus slot.

$f1 references the second focus slot.

The following mpcommands govern the focus system:

mpfocus: Focuses on target player currently in the game, with specified focus slot

mpunfocus: Unfocuses the specified slot.

Memory

In addition to the ability to focus on individual pc’s, a mobile can also "remember"

a pc. Essentially, this is a binary toggle that every mobile has. Given a specific pc,

a mobile either does, or does not "remember" that pc. This memory persists until the mobile

"forgets" the player, or until the mobile perishes.

The following mpcommands govern the remembrance system:

mpremember: Remembers target player

mpunremember: Forget target player if remembers: True if mobile remembers target player

Personal PC Value Fields

If a mobile has "remember"-ed a pc, they gain a single integer field which they associate

with a pc. This operates exactly as the mobile integer memory fields, except that a different

set of commands reference this value, it is associated only with a specific remembered PC,

and (most importantly), it is relative to that particular mob. This means, for example, that

a hen could remember a pc, and set their personal value to 3, while an ethron could remember

them, set their personal value to 5, and both of them would "see" the PC as having their own,

personal value.

The following mpcommands govern the personal pc value fields:

mpmemvset: Sets a value on target player

mpmemvup: Increase a player’s value by one

mpmemvdown: Decrease a player’s value by two

if mobvcheck: Checks a player’s personal value field

PC DATA

Every player has 65,535 binary values associated with their player file. These values can be

toggled or checked by progs, and are permanent, until altered by a mobile or an affect.

By no coincidence, there is a one to one correspondence between vnums and these binary bits.

In general, a builder should only be altering bits which correspond to vnums in his or her area.

The following are commands which can set bits:

mpbitset: Sets a bit to 0 or 1

mpaddaff (using toggleoffaff or toggleonaff to toggle the bit after a specified duration)

if isbitset: True if the specified bit is set to 1