How can I tell which way mushrooms and powerups travel when hitting a ? block?
Solution 1:
There are two things that determine mushroom motion.
- Mushroom type
- Player location
Since the original Super Mario Bros, a Red Mushroom will always move towards the player after it has fully emerged from a block, while a Green Mushroom will always move away from the player after fully emerging.
Most power-up mushrooms will act similarly to a Red Mushroom, including New Super Mario Bros. Mini Mushrooms, as well as Poison Mushrooms from the Lost Levels (even though they decidedly do not power you up!).
Mega Mushrooms, also from New Super Mario Bros, will always take short hops to the right regardless of your position. As will the Helicopter Hat Mushrooms from New Super Mario Bros Wii.
Also, although this question is primarily concerned with mushrooms, Starmen emerging from a block bounce away from a player, similar in behavior to the Green Mushroom.
Solution 2:
(Now that I see the other answer and confusion, I no longer know if this is right. But this is the way I always saw it, and I thought it was consistent.)
It depends on where you hit the block. If you are slightly to the left of center when you hit the block, it'll go right. If you're slightly to the right, it goes left. Likewise, if a shell hits it from the left, it'll go right, and if a shell hits it from the right, it'll go left.
It also may depend on the specific game. This behavior began in Super Mario Bros. 3, and I've never thought to question it since. I believe in the original and "Lost Levels", mushrooms always go right regardless until they bonk into a wall or something similar.
Solution 3:
In my experience, I've noticed that there seems to be a moment right before beginning movement after the mushroom has fully exposed itself where it decides which direction it goes. Which direction it goes I'm fairly certain is determined by where you are positioned in relation to it. As far as I know it will ALWAYS move away from you (as in, whichever direction you are not in relation to it. If you are slightly centered towards the left of it at the moment it triggers, it will move right, and vice versa)
A lot of people also claim that it depends on the position of the question marks. While potentially true, I highly doubt it because I have never paid attention to it, so for me to have recognized this as truth when there was some other perfectly aligning determining factor is almost comically improbable.
When trying to get the mushroom quickly, if there are hazards/a pit nearby, I start on one side, jump under it, move a little further on that side, and begin running underneath the block in order to catch it on the other side.
If there's another determination for which direction it goes, I have no idea what it could be. I've been doing this for years, so if there is a contrary method, then I've just been horribly plagued by misleading coincidence for a long time. Hope this helped! =D