Help with Tweens

General
1

I need help with Tweens. What I want to do is when I swipe right it changes the x pos of a sprite by 160 and when I swipe left it changes the sprites x by -160. But when I swipe an error says “subject must be a table or user data.” I’ve looked at the “Sprites and Tweens” discussion and tried it out but nothing changed. Can someone please help?

2

Here is the parameters tween takes: tween(time, table holding object(s) you want to change, table including new values for those you want to change, tween type, callback)

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So, if the x is a global variable, you need to do something like this tween(1, _G, { x = x + 160 }, tween.easing.linear)

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Explaining the parameters:

  1. Time: I chose a random 1 second, you can change it to your liking
  2. Table 1: `_G` is the table in which global variables are stored
  3. Table 2: This table includes an x value which is the current x value + 160, so it will change x to be 160 more
  4. Tween Type: I chose the default tween type, you can pick a different one if you want a slightly different effect
  5. Callback: I didn't put a callback, but you can add one if you need it for something else.

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Hope this helps!

3

I just don’t get the _g part! is that what I would put or what?

4

Sorry, that wasn’t supposed to be an explanation point, it was supposed to be a coma

5

Also, the x variable is Pcar.x (Player car)

6

_G is just a table holding all the global variables.
So you car could be a table like:

Pcar={x=WIDTH/2,y=HEIGHT/2}
If (swipe right) then
    tween(1,Pcar,{x=x+160})
end
7

this will change Pcar.x from its current value to it plus 160 pixels, in 1s.

tween(1, Pcar, { x = Pcar.x + 160 })
8

@Coder are you sure about {x=x+160})? The second x here is a global variable named x, and not a field of Pcar. This is why i wrote { x = Pcar.x + 160 }

9

@Jmv38, you are correct. I think @Coder was thinking about global vars.

@CrazyJoe73, I explained _G in my first post, but since you are using Pcar.x, Jmv is correct.

10

@Jmv38 yes I think you are right

11

Dang it I don’t know why but none of this is working. I’ll just give some code and maybe it will help. This is the sprite and tween code:

sprite(self.costume,pcarx,self.y,self.w,self.h)

tween(2, pcarx,{pcarx == Pcar.x + 160},tween.easing.quadInOut)

I made Pcar.x equal to pcarx unless it is moving right or left and then is equal to it again after it stops

12

I still get this:

error: [string “-- tween.lua …”]:98: subject must be a table or userdata. Was 592

Or when I make the object Pcar instead of pcarx I get this:

error: [string “-- tween.lua …”]:54: Parameter ‘1’ must be a number or table of numbers

13

outch! So Many may errors just in 2 lines of code. Impossible to help you properly Ith just those 2 lines.Post all the code if you want some help.
And put the code between blocs of ~~~ to keep it in blue.

14

One of the problems is thatpcarx is a variable not a table. Tweens require tables so:

pcarPos={x=0,y=0}
tween(2,pcarPos,{x=pcarPos.x+160},tween.easing.quadInOut)
15

@Coder You accidentally have tween.easing.quadInOut inside the table.

16

@SkyTheCoder Thanks

17

@CrazyJoe73, if you use the pcarx variable, you need to use _G for the table, as I mentioned above.

18

It finally worked! I just tweeted up coder’s code and did the _G as the object. Thanks for your help all of you!