View source for Manual:DIL Manual/SFB PRE



<span id="sfbpre"></span>

 SFB_PRE            Command preprocessing

   When this flag is set, the program is activated by a few special events
   which can then be blocked or changed. Currently, this event is triggered
   just prior to a spell being cast, and just prior to any sort of damage
   being given to a target.

   PRE "command(CMD_CAST)"

   Assume a a spell is cast from player A on player B with a scroll C.

      'activator'... is a unitptr to A.
      'medium'   ... is a unitptr to C.
      'target'   ... is a unitptr to B.

      command(CMD_CAST) will evaluate to TRUE.

      'argument'.... will contain a number followed by any
                     argument to the spell itself. You should
                     parse this number, it equals the spell number SPL_XXX.
      'power' ....   is set to 'HM', i.e. how powerful the spell cast
                     is going to be. YOu can change this number at will.
                     If you decide to block the spell, you ought to set it
                     to -1.

 Example:
    wait(SFB_PRE, command(CMD_CAST));

    s := getword(argument);
    splno := atoi(s);

    if (splno == SPL_FIREBALL_3)
      power := 0; /* No damage */
    ...


   PRE "command(CMD_AUTO_DAMAGE)"

   Assume that damage is given from player A to player B with a sword C.

      'activator'... is a unitptr to A.
      'medium'   ... is a unitptr to C.
      'target'   ... is a unitptr to B.

      command(CMD_AUTO_DAMAGE) will evaluate to TRUE.

      'power' ....   is set to how much damage will be given. You can change
                     this number at will, but you should not set it to less
                     than zero.

      'argument'.... will contain three numbers that you must parse to
                     determine what kind of damage we're talking about.

                     First number is the attack group, this can be one of
                     MSG_TYPE_XXX from values.h and/or vme.h.

                     Second number is dependant on the attack group and
                     identifies what damage compared to the group. For
                     example WPN_XXX for weapon group.

                     Third number is the body hit location, one of WEAR_XXX,
                     (but not all of them, just hands, feet, legs, body, head,
                      arms, i.e. the armour positions, not positions like finger
                      or ear).


 Example:
    wait(SFB_PRE, command(CMD_AUTO_DAMAGE));

    s1 := getword(argument);
    grpno := atoi(s1);

    s2 := getword(argument);
    atkno := atoi(s2);

    s3 := getword(argument);
    hitloc := atoi(s3);

    if (grpno == MSG_TYPE_SPELL)
    {
       if ((s2 == SPL_FINGER_DEATH))
       {
           act("Your scarabaeus lights up as it protects your life force.");
           power := -1;
           block;
       }
    }
    ...


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 '''<i>A note upon activating a DIL program</i>'''

 This is what you can't do:

   If a DIL program is already active, e.g. it is sending a message or
   perhaps using "exec" to perform an action, then it can not be activated.
   Thus, any active DIL program is unable to catch further messages.
   Imagine this setting:

   You have five program P1..P5. P1 sends a message, which is intercepted
   by P2. P2 now sends a message, but since P1 is busy it can not process
   the message. P3..P5 are however possible candidates.
   Assume P3 sends a message, and P4 acts upon it. P4 now sends a message
   and the ONLY program which can catch it is P5, since all the other programs
   are "busy". If P5 sends a message no-one can act upon it. When P5
   returns, so does P4, P3, P2 and finally P1.