Directional Pickle w/ Angles

I'm trying to figure out a way to retrieve a special directional value from Object A's position, facing Object B. I retrieved the angle easily using the VAngle function.


I have two problems though...

1) The trick is, I'd like to convert this to 8 directional values, 0 to 7. However, using Floor(Angle/45) gives rather uneven results. Using Round (Angle/45) works better, but the problem is that for the last 22 degrees it rounds the value up to 8. Is it possible to somehow use an expression to make it jump back to 0 at this point, or will I need an extra event telling it to do so?

2) I'm trying to figure out how to make Object A turn to face Object B; turning in the direction that will reach the desired angle faster. I managed to achieve this using multiple events, but once again I'd like to sum this up with a single expression by somehow retrieving a positive or negative value (turn left / right). Can it be done?

1. Round(Angle/45) mod 8

2. Though this is not one event, the iea still might be of use. Before you make Object A turn towards Object B, calculate the difference in angles between the two directions and store them. The direction with the lower absolute value (you don't need to store the angle difference with the absolute value) is the quicker direction.

You might get some complications with getting Object A to face Object B instead of getting Object A point in the same direction of Object B, but the concept should still hold.

Update: Looks like schrodinger has a quick and simple equation that you want for part 2.

2) ATan2(sin(current_angle-target_angle),cos(current_angle-target_angle))

will give you the signed (+/-) angular difference between current_angle and target_angle
through shortest path :)

edit: re-reading your post, target_angle would obviously be OAngle("object",Xobject1,Yobject1)

...assuming that with "facing" you mean "pointing at" as ProdigyX points out


1) this I think I don't understand - you need a direction (0-32) from the angle you already have, but you need it to be...?

edit2: re-reading again I guess I understand now.. sorry! ProdigyX already answered anyway X)

Wow, you guys never cease to amaze! Thanks :)

1) I keep running into the mod function in many of these magical expressions, I need to read up on that.

2) Works great! I even managed to get the value range of -1 to 1 I was looking for by dividing the result with Abs(result). However, I'm not sure I understand the difference between "face" and "point in the same direction" :o

1) agreed - mod uses are subtle but more useful than one could think of!

2) yeah that little expression is rarely seen around but it's hugely useful, I've been using that extensively lately and it never failed :D

I guess the doubt on "facing" could be at a quick read if one or both objects were to switch "direction" / or both to face each the other's face,
though reading well how you wrote it it was effectively pretty clear. But with math and angles always better double-checking XD

'Mod' is just another operator like + - / *
But not as commonly used

What 'X mod X' does is return what is remaining after a division

Example:
5 / 2
2 goes 2 times inside 5 -> So this calculation returns 2

5 mod 2
2 goes 2 times inside 5 ( leaving the number 1 remaining ) -> So this calculation returns the remaining 1

'Mod' is just another operator like + - / *
But not as commonly used

What 'X mod X' does is return what is remaining after a division

ExampleA:
5 / 2
2 goes 2 times inside 5 -> So this calculation returns 2

5 mod 2
2 goes 2 times inside 5 ( leaving the number 1 remaining ) -> So this calculation returns the remaining 1

ExampleB:
7 / 4
4 goes 1 time inside 7 -> So this calculation returns 1

7 mod 4
4 goes 1 times inside 7 ( leaving the number 3 remaining ) -> So this calculation returns the remaining 3

...
EDIT: Not sure what happened with the double post, i just edited the first one

Mod is really useful for wrapping values. I use it a lot to make a timer loop back to 0 :P

(timer value+1) mod wrap value

Ah, that explains alot! So it turns out I've actually used mod before, as %, when messing around in C++

Thanks for clearing things up guys :)

Hmmm, so the symbol for mod is %
That could be confusing
I think it deserves its own symbol