Understanding the double Thunder Hammer

[Prog]

Some people wonder what happens when two Goblin Tanks use their Thunder Hammer on each other at the same time. Until today I thought that the player with the lower number always gets his stun first (which was a pretty good excuse when playing light force), but today after mentioning it the answer was disbelieve. So a couple of us got into a private game and tested around. Quickly I was proven wrong, but nevertheless there was a strange behavior. Rarely we got double-stuns. I don't believe in randomness, so I looked for an answer and programed a testing ground into the latest open source version of battle tanks.

All tests used this basic triggers:
First:

Code:

Events
Player - Player 1 (Red) types a chat message containing reset as An exact match
Actions
    Unit - Pause all units
    Unit - Unpause Goblin Tank 0183 <gen>
    Unit - Unpause Goblin Tank 0186 <gen>
    Unit - Set level of Thunder Hammer (Goblin Tank) for Goblin Tank 0183 <gen> to 4
    Unit - Set level of Thunder Hammer (Goblin Tank) for Goblin Tank 0186 <gen> to 4
    Unit - Move Goblin Tank 0183 <gen> instantly to (Center of Team 1 Tank Respawn Move <gen>)
    Unit - Move Goblin Tank 0186 <gen> instantly to (Center of Region 045 <gen>)
    Unit - Make Goblin Tank 0186 <gen> face Goblin Tank 0183 <gen> over 0.00 seconds
    Unit - Make Goblin Tank 0183 <gen> face Goblin Tank 0186 <gen> over 0.00 seconds
    Unit - Set life of Goblin Tank 0183 <gen> to 100.00%
    Unit - Set life of Goblin Tank 0186 <gen> to 100.00%

Second:

Code:

Events
Player - Player 1 (Red) types a chat message containing test as An exact match
Actions
    Unit - Order Goblin Tank 0183 <gen> to Neutral - Firebolt Goblin Tank 0186 <gen>
    Unit - Order Goblin Tank 0186 <gen> to Neutral - Firebolt Goblin Tank 0183 <gen>
    Unit - Order Goblin Tank 0183 <gen> to Human Mountain King - Storm Bolt Goblin Tank 0186 <gen>
    Unit - Order Goblin Tank 0186 <gen> to Human Mountain King - Storm Bolt Goblin Tank 0183 <gen>

(I didn't know which spell was the basis of the thunder hammer and was lazy, so I used both possibilities)

At first I looked for a random spot to test:

   

I tried this with three different player and position combinations: Blue vs Orange, Red vs Orange and Orange vs Red (switched up the positions). In total the Goblin Tank from one position (in the picture the one in orange) won (first stun) far more often. I tested until one side won 20 times.

Blue vs Orange results: 6x Blue, 20x Orange, 2x Draw.
Red vs Orange results: 10x Red, 20x Orange, 3x Draw.
Orange vs Red results: 3x Orange, 20x Red, 2x Draw.

It looked like it had something to do with the positioning, but it also looked like red did better than anyone else. But the samplesize was small so I needed a better way to find out. So I came up with the second setup. I tried to flatten a ground to test the difference of Player 1 vs Player 6. I saw a landslide victory for red. Out of 30 tries red won 29 times, with 1 draw. Then I switched up the places and suddenly orange won pretty much every attempt. Soon I found out that it wasn't really flat. One Goblin Tank started a little bit on high ground. And this Goblin Tank nearly always won.

   

So I flattened the ground again. Now it was a draw every single time. The ground decides who wins.

   


But I wasn't satisfied. I formed this suspicion that it has some relation to the movement speed. Cobra had this idea in our first tries in the private game that if you wait until the other goblin is already close and start moving towards him only at that point, then you will always get stunned first (because the other Goblin Tank already has the speed buff). But it goes further than that. I gave one of my Goblin Tanks the Goblin Speed Skill on lvl 4 and then started the brawl on flat ground. He won every single time. 20 out of 20.
   
(ignore the bounty/respawntime/speed 1, that is not correct because those tanks are just placed there and not part of the normal triggers)


Based on this I give you my theory on Goblin Tank stuns: The tank with the higher momentum always stuns first. With even momentum both stun at the same time. Uneven terrain influences your momentum in a way that is sometimes difficult to predict so the stun effect can seem random. In some cases even a minimal difference can be the deciding factor. Minimal differences that can explain why a setup that looks the same to us can have different results if there is a difference on one position that is not visible for us but is still calculated in the game. This explains why in my first setup the result was not as clear as with the later ones.

I put this here under strategy, but I personally think it should be fixed to always stun both, if there is a possibility (I'm not sure there is one). The map is not flat and that may create imbalance. Also buy Speed Boosts if you play Goblin vs Goblin.

[Exodus]

Very interesting read, thanks for that! Also an interesting way to use the open source map ;)
I'm actually suprised that you could create situations where the outcome is always the same, as I expected the Wacraft engine to be more erratic in that way.

Generally, there is no way to "fix" this kind of thing. Warcraft has an internal way of handling command chains and issuing them and this I cannot change. There is another way however, a special case for the Goblin Hammer, if you will.

Despite everything, the Goblin Hammer uses a projectile, which stuns on hit. This projectile is invisible and has infinite movement speed (set to 0). The skill has a cast range of 150, so if you would set the movement speed to - for example - 300, it will take half a second for the stun to actually hit, giving both tanks enough time to cast their skills, regardless of terrain or their own movement speed. This should always lead to a double-stun situation, but will obviously also affect other situations, giving the target more time to escape.