How 200, 201 & 259 opcodes calculate the 'spell level'

[Ardanis]

During tests I seem to have found out how exactly 'Decrementing Bounce Spells [200]', 'Decrementing Spell Immunity [201]', 'Spell Trap [259]' opcodes (D&T in further) determine how much of the level allowance they've just wasted, as well as what is affected by them and what's not.

 

When determining whether or not the incoming spell is going to be negated, it looks at the power level (PL) of effects within the incoming's ability header. Those effects are then divided into two groups, one consists of those whose PL exceeds the level allowed for D&T (1-7 for Minor Spell D&T, 1-9 for the rest), and the other gets all the deflectable effects.

The first group is completely unaffected by D&T and goes through as if it wasn't there.

The second group is D&Ted as a single one. The D&T's spell level capacity (4 for Minor Spell D&T, 10/12 for Spell D&T, 30 for Spell Trap) is decreased by the group's PL. The latter is equal to PL of the effect with the lowerest index (shows at the top of the list in DLTCEP and NI) within the group. It is possible to change the group's PL by mere switching two effects places.

 

The division into two groups, one that passes and one that's stopped, is also true for immunity to spell levels (102).

 

 

Example.

 

We take Magic Missile, strip it of ability headers responsible for caster level beyond 1 (just for conveniance), remove it's original effects as well and create new ones - 1st has PL=2 and deals 2 damage, 2nd is PL=9 and deals 9 damage, 3rd is PL=5 and 5 damage. Then we have another character to cast Minor

 

Spell Turning (reflects 4 levels of spells up to 7th level) and start bombarding him with modified MM.

 

Round 1.

MST splits MM's effects into 2 groups:

1) unaffected - PL=9, which is '9 damage'

2) affected - PL=2, PL=5, these are '2 damage' and '5 damage'. The one with PL=2 is the first, so the group's PL=2.

Target suffers 9 HP loss, the original caster gets back the 2+5 worth of hurting.

The MST loses 2 of 4 levels of allowance and remains active.

 

Round 2.

Damage distribution is the same. The MST loses another 2 levels and dissipates.

 

 

Now, lets change places the 1st (PL=2) and the 3rd (PL=5) effects. Another round of MM bombarding begins.

 

Round 1.

MST splits MM's effects into 2 groups:

1) unaffected - PL=9, which is '9 damage'

2) affected - PL=2, PL=5, these are '2 damage' and '5 damage'. The one with PL=5 is the first, so the group's PL=5.

Target suffers 9 HP loss, the original caster gets back the 5+2 worth of hurting.

The MST loses 5 of 4 levels (since for as long as at least 1 level remains it can still negate any allowed PL) of allowance and dissipates.

[Avenger]

Ok, so, an effect blocks's 'spell level' is simply the first effect's power level. <--- heh, i could summarize your whole topic in a single sentence?

 

What about simple spell level immunity (like the one in minor globe)?

[devSin]

What about simple spell level immunity (like the one in minor globe)?

It's irrelevant? The engine doesn't have to use a level (for changing the remaining level of absorption/deflection), so it's handled per-effect.

[igi]

Added, thanks.