Help understanding (Mathf.Round(damageDelayCount * 10) % 2 == 0)

Unity Engine
1

Hi,

I’m following a tutorial, and the instructor kind of glazes over this part ( as if I should know already ), but I’m having a little bit of trouble understanding the statement. So, for context

This is initiated from the Update method

if (damageDelayCount > 0)

In the method we have, which obviously decrements damageDelayCount over time

damageDelayCount -= Time.deltaTime;

then later we have

if (Mathf.Round(damageDelayCount * 10) % 2 == 0)
// Do stuff

I know it’s related to the countdown, so that when we hit 0 it does ‘do stuff’ part of the code, however, having a little trouble understanding the * 10 ) % 2 portion of the code, I kind of know what it’s doing, but would like a simple English explanation of exactly what it’s doing, just so I can add in my own comment in the code to understand it at a later date. ( ? Multiplying by 10 to make it easier to use the Mathf.Round function when counting down ? )

BTW, I’ve already repurposed the logic to be ( because vs doesn’t like the == 0 comparision )

if (Mathf.Approximately(Mathf.Round(damageDelayCount * 10) % 2, 0))
// Do Stuff

Thanks

2

Hi @ ,
Looks somewhat convoluted to my eye. But, If you print out the results of that calculation, it looks like it could be just used to add a sort of random behavior so that the code stays compact. Sometimes it might be 1-5 updates before the modulo operation value is 0. And you are right, when the damageDelayCount is multiplied by 10, it’s to get a bigger number that is a value in some range, depening on the input. Anyway just do a few debug prints (print the delay, rounded value, and the modulo result) and you will see quickly how that logic exactly works.

1 Like
3

The % is called the remainder operator, it divides the first number by the second and returns the remainder of the calculation. So, 5 % 2 would return 1, 4 % 2 would return 0.
Basically, in your example, the statement is checking if the rounded value you supply (Mathf.Round(damageDelayCount * 10) is a multitude of 2.

1 Like
4

@Team2Studio it’s more commonly called modulo operation. That’s what it is called in C#, and same goes for HLSL and many other languages. It does find the remainder but it’s not called remainder operator.

5

@Olmi it is called the remainder operator in microsoft docs for C# reference

6

@Team2Studio @Olmi

Thanks for the replies, that makes much more sense now. For some reason, I had divide by 2 in my mind, hence the confusion, but the remainder operator makes much more sense.

Kind Regards

BTW : The full code is used to ‘flash’ an object a set number of times before the damageDelayCount reaches 0, also, during which time the Player is unable to be damaged again.

1 Like
7

@Team2Studio looks like my head has bad sectors today. I stand corrected, you are right about the docs.