Time.time in unity - time

Question

i see a video of how to move a cube like snake game move
HI
in this video ( https://www.youtube.com/watch?v=aT2zNLSFQEk&list=PLLH3mUGkfFCVNs51eK8ftCAlI3hZQ95tC&index=11 ) he declare float name **lastMove **with no value (zero by default) and use it in condition and **minus **it with Time.time then assign it to **lastMove **.
my question is what is the effect of lastMove in condition when it has no value?
if i clear it from "if statement" the game run fast but if remain in "if statement" time passed very slower

Answer 1

What he does is check continuously if time - lastMove is bigger than a given predefined interval (timeInBetweenMoves). Time keeps increasing each frame while lastMove is fixed. So at some point this condition will be true. When it is, he updates lastMove with the value of time to "reset the loop" = to make the minus difference lower than the interval again.The point of doing this is to move only at a fixed interval (0.25 secs) instead of every frame. Like this:
interval = 0.25 (timeBetweenMoves)
time (secs) | lastMove | time - lastMove
-----------------------------------------
0.00 | 0 | 0
0.05 | 0 | 0.05
0.10 | 0 | 0.10
0.15 | 0 | 0.15
0.20 | 0 | 0.20
0.25 | 0 | 0.25
0.30 | 0 | 0.30 ---> bigger than interval: MOVE and set lastMove to this (0.30)
0.35 | 0.30 | 0.5
0.40 | 0.30 | 0.10
0.45 | 0.30 | 0.15
0.50 | 0.30 | 0.20
0.55 | 0.30 | 0.25
0.60 | 0.30 | 0.30 ---> bigger than interval: MOVE and set lastMove to time (0.60)
0.65 | 0.60 | 0.5
0.70 | 0.60 | 0.10
...
This is kind of a throttling.