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June 27, 2019

Bug Hunt VI

Bug Hunt VI

This is yet another post that will look at some important, interesting or just funny bugs in StarCraft II Co-op. Previous posts are here: #1, #2, #3, #4, #5. I would like to thank everyone who either notified me about bugs or reported them on the official bug report forum. Today's list is:

Mecha Baneling & Bonus Damage

Update: This issue has been fixed in patch 4.10.0

Stetmann's Mecha Banelings don't deal bonus egonergy damage if they are killed, or if they use their jump ability.

The trigger handling bonus damage requires Mecha Banelings to use a special BanelingStetmannDamageTrigger effect (image below). Mecha Banelings use this effect when attacking without jumping or while ordered to explode manually, however, this effect isn't used if they jump or are killed.

The trigger controlling bonus damage for Mecha Banelings

So right now you should choose either their Jump ability or bonus damage, as they won't work together. And one more note, damage after jumping (or when they are killed) isn't increased by melee upgrades.

Mecha Baneling & Structure attack

Update: This issue has been fixed in patch 4.9.3

Since we are already talking about Mecha Banelings, their Enable Structure Attack ability doesn't do anything. I don't know who actually uses it, but it might be interesting to see how it works.

Banelings and similar units have usually two weapons ⁠– one that doesn't auto-attack non-threatening structures, and another that does. This ability switches between their two weapons. However, in the case of Mecha Banelings, neither of their weapons is in the list of weapons to enable/disable, and so the ability does nothing.


Update: This issue has been fixed in patch 4.10.0

Corsair's Neutron Flare weapon's splash damages even invulnerable units. This includes respawning Stetellites, Gary's E-Gorbs or even units with active Guardian Shell.

Corsairs punching through the Guardian Shell

Lava on the Vermillion Problem

Update: This issue has been fixed in patch 4.10.0

Lava on The Vermillion Problem won't damage ground units if they stand in certain areas.

Special credit to NightSky, JamesRaider and Terrazine for their video showcasing this.

Top 10 lava bathing spots on Veridia Prime

What's particularly interesting is how lava damage is done. Lava itself doesn't do any damage, the damage is instead handled by invisible units that rise up together with lava (image below). They deal damage only to units at similar height, and so they are dangerous only during lava surges. However, they don't cover everything that's consumed by lava.

Invisible units (selected spheres) that handle lava damage

Missions not ending

Update: This issue has been fixed at some point the way I suggested

In previous bug hunts I have talked on two occasions about the issue where missions wouldn't end. I have suggested that RunMissionVictorySequence could wait only for a limited time before proceeding. This was eventually implemented. However, I was wrong to think this alone is enough.

After the mentioned trigger, there is another one that waits for all transmissions to be completed (image below). But the original problem was that a transmission got stuck and is still active. This hasn't changed, and so the trigger will wait indefinitely and prevent players from reaching the victory.

VictoryFanfareQ waits for all transmissions

I was lucky to get this bug myself (replay). Before you could at least try to pause/un-pause, but that's impossible now. The only option seems to be to wait until one player leaves the game.

Possible fixes would be to try clearing stuck conversations at the end of RunMissionVictorySequence, or add a similar time limit when waiting for all transmissions to end.

Missile Command & Minimap

Update: This issue has been fixed in patch 4.10.0

Minimap icons from the Missile Command mutator don't disappear.

Minimap is getting crowded

This is likely due to this change in patch 4.9.2

However, it hasn't affected just Alien Incubation. This also means that missiles won't trigger Fatal Attraction, Black Death or Scorched Earth mutators, and their minimap icons won't be cleared either (image below).

We will have to see how this bug is handled and how will Missile Command interact with other mutators in the future.

Minimap icons aren't cleared

Trains & Conjoined Behavior

Update: This issue has been fixed in patch 4.11.0

This one is caused by inherent limitations of how trains work currently. Each train car is a separate unit, and they need to sync their life somehow. They do this through a conjoined behavior. This behavior sync their life each game tick, and sets it to the life of the most damaged unit in the group.

The problem is when you deal damage to more than one unit in a group during one game tick. Lets say you deal 100 damage to one car, and 101 damage to another car. You would expect 201 damage to be done, but the health will go down by only 101. So focusing one train car and minimizing ignored damage is often better.

I have done few tests to illustrate this effect. It's particularly impactful for units that need high surface area (e.g. Zerglings), or units that deal splash damage (e.g. Mutalisks).

Unit Note
Damage ignored
Dark Templar front attack + Shadow Fury
Mutalisks any attack pattern
Swarmlings wide spread

This also makes final damage score inaccurate, but more on that in the next part.

Trains & Just Die!

Post-game train-damage score can be highly inaccurate on Oblivion Express with Just Die! mutator. Often one player scores even negative train damage.

This is related to the conjoined behavior described previously and how the score is handled. You cannot just count damage done to trains, it would lead to different results each game which would be confusing. Instead, a trigger compares current and previous train states (image below), the difference in health is then added to the score.

There are two issues with this. With Just Die!, the difference in train health just after the train resurrects will be very high and negative. It will still be added to players' score – often making it negative.

The score will also be generally inaccurate in all games even without this mutator. Some damage will be ignored, and all effective damage done during one tick will be counted towards the first player that deals damage after synchronization.

Trigger handling train damage score
One additional note, the issue with Just Die! that caused only one train from double waves to resurrect is fixed.

Toxic nests

Update: This issue has been fixed in patch 4.10.0

Toxic Nests can kill even invulnerable units. The best example of this is that they can destroy normally invulnerable Kill Bots.

Kill Bot getting killed by Toxic Nests

You need to detonate them manually, and Kill Bots can take several hits, and so you can't rely on Toxic Nests alone. This also won't work on Polarity.

Another interesting fact about Toxic Nests is that with Eminent Domain mutator, they immediately switch to Amon after exploding. This makes using them very dangerous, and should be left to situations where you will never have to walk over them (for example for some spawn-camping spots). Spawning Toxic Nests to your ally mineral line is also one of the worst things you can do.

Toxic Nest harass

Chronoboost & Morph

If mastery-improved Chronoboost is applied to a morphing Lair or Hive, its animation and actual morphing speeds will be different. The animation will finish first, its new model will be visible, but the Lair or Hive won't be finished for some time.

Morphing Hatchery that visually looks finished

There is no issue with basic Chronoboost as it doesn't increase morph rate. However, masteries that improve Chronoboost make it to increase morph rate by up to +30%. Or they would, if it worked correctly.

Increased morph rate does reduce animation time properly (table below), but the actual morph time is only reduced by truncated morph rate (e.g. 1 from 1.99). This makes it that Karax's Chronowave with 2 morph rate is working correctly, but 1.99 morph rate would lead to 30s discrepancy. So perhaps this is some issue with data types?

Morph rate Animation time [s] Morph time [s]
1 60
1.3 46
1.99 30
2 30 30

Infested Diamondback's Weapon

There are more things wrong with this weapon:

  • Weapon period and damage point are different based on target distance
  • Mech Attack Speed mastery doesn't increase attack speed of Inf. Diamondbacks
  • Inf. Diamondbacks don’t get Vorazun’s damage bonus if they’re cloaked
  • Weapon damage ignores armor

Vorazun's Strike from the Shadows doesn't increase spell damage, and Inf. Diamondback's damage is set to spell-type. As for armor reduction, it has to be set manually but it was left at zero.

But by far the strangest thing about this weapon is that its effective weapon period (the time between attacks) and effective damage point (the time between the unit starting to attack and it dealing damage) change depending on how far the target is.

In the following table there are values for melee range (1 distance), maximum range (8) and 20 distance to see what would happen at that range.

Distance Effective weapon period [s] Effective damage point [s]
1 1
8 1.6875 0.8125
20 2.25 1.375

It's clearly worse the farther you are from the target. This weapon is strange, it looks like a missile weapon that actually wants to be a beam weapon instead.

It might be better to completely remake it. But the simplest change might be to use one-phase very fast missile mover—making it more like a beam weapon. That itself can get period down to correct 1s and damage point to 0.125s at 8 range.

Mastery would still have to be fixed in another way. For example each mastery point could increase PeriodicEffectRateMultiplier on StukovInfestedDiamondBackBileStreamSprayInitialCP by
0.015. This gives the correct +15% attack speed at 15 mastery and +30% at 30 mastery.

Final Note

This concludes the sixth edition of bug hunt. As always, if you encounter any bugs yourself, report them on the official bug report forum.

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