In theory, it could do either -- there's no way of knowing from just looking at a screenshot -- but I'd assume that normally, it's simulating the physics and looking at where the ball winds up to determine the score, and that if the physics engine is deterministic, that any variation from launch to launch in a pachinko simulator would come from slightly varying launch speed and angle.

If you can manage to get a ball stuck in a game, or if the game can fire multiple balls simultaneously, then I'd say that'd be consistent with it just simulating the physics and determining the outcome from where the ball winds up.

I don't really know what the benefit to computing a result in advance would be, unless one has a model that optimizes for player engagement or something.

In case of that particular game, it’s rigged to fuck. Anything that tries to get you to spend money is going to be. So I’d say a previously calculated result dictates the outcome.

This question isn’t only for mobile game. I remember asking myself this very question with Super Mario Land on Game Boy when finishing a level and you had a chance to get 1up 2up 3up or a mushroom.

If the animations look realistic, it's almost certainly not predetermined. That's by far the simplest way to get the desired effect. However, that doesn't mean it's fair. It could easily use a real physics engine, but still subtly rig the system. For example, bounces off of the pins could have an elasticity factor of 0.4 for bounces towards the big prize, but 0.5 for bounces away from it. Or maybe the hitboxes on the center pins are just a little bit bigger. Stuff that will noticably affect the large-scale statistics, but that you're not gonna notice with your eyes.

The cheapest way to do this is to let the animation (the physics simulation) determine the result.

Picking a bin for the ball to go into, then working backward from that to an animation that looks like it’s following the same physics at other animations, is far more computational work.

Therefore, my money is on the animation determines the result. Now, it may be pre-determined from parameters, but that doesn’t mean it’s predictable, due to a concept called “computational irreducibility”.

It could actually depend,

You could derive the result from a pseudorandom value and then call an animation to reflect that result, or you could derive it from building the visual in a game engine and just letting it play same as it would if it was a physical version of the game.

If I had to guess I'd imagine a mobile game might lean towards the RNG option simply because I personally would estimate it would be less of a burden on the hardware, which for mobile gaming can be a big deal.

Just like every video game, your odds can be heavily rigged against you if the developer wants it.

Use this game as an example. No one's going to recognise if the developer does intentional weighting (guiding the ball towards smaller wins via additional small vectors other than bouncing)

On a carnival game, game host could use a weighted die to rig the odds towards it? On a video game, developer controls everything.

The easy way if doing this is just using a physics engine and calculate the result depending on where the ball lands. Prototyping a game like that would take me a few hours probably.

That being said if the game asks for money to do anything it's highly unlikely that that's what it's doing, instead it's probably choosing your result based on how much do they want you to win and then calculate a path for the ball that gets this result.

Something that makes it difficult to do this second alternative is if you have some semblance of control, e.g. if you choose the strength to use for the ball or something, that makes it slightly trickier to pull off because you're against the clock on finding a path and might end up with an unrealistic move (however if those round things make the ball kick around like they do on a pin all machine they can be used to set the course you want).

Long story short it's easier to do the animation deciding the result but if the game asks for money in exchange for anything in-game it's more profitable to do the results deciding the animation.

Physics engines are rarely deterministic, which means most of these games use what you would call the "animation deciding results"

It is very rare that it works the other way around contrary to what others have commented it is non trivial to make weighted deterministic random in this manner

While technically possible, only very specialised games with reasons good enough to budget the programming required will go the route you describe as "result calculated before the animation"

I've played that mini game, definitely don't think it's rigged. I've gotten max points plenty of times, it's just hard since the 10 is in the middle and there are obstacles in the way. I would guess they fuzz the plunger so you can't memorize the perfect location for max points every time.