Blizzard 3, Blizzard 3, Fire 3, Fire 3. Repeat.
Since AF/UI don't apply to you until the triggering spell hits your target, both casts of Blizzard (respective Fire) will be cast with the effects of Astral Fire (resp. Umbral Ice) active. The second cast of each spell, however, will impact the target after your buffs change to the opposite set. In other words, this sequence of events occurs (initially, assume AF3 is up):
- You start casting your first Blizzard 3. Since AF3 is up, it costs 80 mana and has a 1.75 second cast time.
- Cast finishes and the projectile leaves your hands. You start casting the second Blizzard 3. AF3 is still up so it also costs 80 mana and has a 1.75 second cast time.
- The first Blizzard 3 projectile impacts the target, switching your buff to UI3.
- Second Blizzard 3 cast completes and the projectile leaves your hands. You start casting the first Fire 3. UI3 is up, so it also costs 80 mana and has a 1.75 second cast time.
- Second Blizzard 3 impacts the target and refreshes UI3.
- First Fire 3 cast completes. You queue up the second Fire 3 cast, still under the effects of UI3.
- First Fire 3 impacts the target, switches your buff to AF3.
- Second Fire 3 cast completes, you begin casting the first Blizzard 3 of the next cycle.
- Second Fire 3 projectile impacts target, gets full damage buff from AF3.
The cycle is four casts long, each of them 1.75 seconds due to the cast speed increase from the opposite AF/UI buff. The Blizzard 3s do 220 potency each, the first Fire 3 220*70% = 154 potency (30% damage penalty from UI3), and the second Fire 3 220*180% = 396 potency (80% damage bonus from AF3). That's (2*220+154+396)/(4*1.75) = 141.43 potency per second. The complete cycle costs 4*80 = 320 MP, and you spend 3.5 seconds each cycle in UI3 so you'll get a mana tick. Effectively, mana will never dip below 90%.
Contrast with the typical rotation: B3,T2,F3,F1,F1,F1,F1,F1 with T3 on cloud procs and F3 on Firestarter. Ignoring procs, cycle length is 1.75+3+1.75+1.25+4*2.5 = 17.75 seconds with 220+(50+6*35)+220*70%+150*180%*5 = 1984 potency. An average cycle will have 6*5% = 0.3 cloud procs that add (60+8*35)= 340 potency and 2.5 seconds of cast time. We expect 5*40% = 2 Firestarter procs, each will add 220*180% = 396 potency and 2.5 seconds. Altogether, that makes for an expected 1984+0.3*340+2*396 = 2878 potency over 17.75+0.3*2.5+2*2.5 = 23.5 seconds, resulting in 122.47 potency per second.
What about B3,B3,F3,F3,F1,F1,...,F1, i.e, augmenting the rotation with some casts of Fire 1 w/ Firestarter during the AF phase? With AF3, a Fire 1 does 150*180% = 270 potency over 2.5 seconds, with a 40% chance to proc Firestarter for an additional 220*180% = 396 potency over 2.5 seconds: expected DPS is therefore (270+40%*396)/(2.5+40%*2.5) = 122.4 potency per second. That's less than the proposed rotation's expected DPS of 141.43 potency per second - casting more Fire 1s would *lower* the DPS.
Stuff to test:
- Is it true that spellcasts get the mana cost / cast speed effects from the active AF/UI stack at beginning of cast, and the damage multiplier effects from the active AF/UI stack at time of projectile impact?
- Does the cast speed reduction effect apply properly to the GCD as well?
- Do damage parsers reflect the theoretical relationship between the two cycles, or is something missing from the theory?
Edited, Oct 2nd 2013 1:55pm by cartec