Hourglass visualization algorithm

How can I program hourglass behavior (similar like on picture) for my game?

Should I make something like gravitation and process each grain of sand?开发者_StackOverflow

What about digital hourglass (like on this clocks)?

Wasting effort on a "proper" simulation for grains of sand for the sake of an in-game hourglass is serious over-engineering.

Get an artist to produce a high-quality animation and either render it as a series of static images or as a movie.

Seriously, don't simulate the sand.

Tangentially, you can model falling sand with cellular automata. I'd not considered using it for an hourglass simulation, but in principle it might work quite nicely, and be a fun project.

Looking at your digital hourglass -- either the grains move in set patterns, or it might use something like this CA.

Modelling it is making a rod for your own back, you'd be better off just drawing the frames by hand and playing them back.

But -- if maths is your thing you could:

• work out the volume of sand in the top.
• define a rate of volume flow through the neck (keep this arbitrary as you'll want to tweak it).
• at any given time you can use the flow rate to work out how much sand has left the top.
• if you know the shape of the top vessel you can work out the current height of sand given the current volume of sand.
• if you know the shape of the bottom vessel you can work out the current height of sand given the volume of sand that's flowed through the neck.

I will play devil's advocate here and assume you actually want to simulate sand in your game not just create a simple hour glass loading indicator (as people have said it would be a waste of effort).

So I go back to my initial comment. What kind of resolution are you looking for?

Chances are you don't need to simulate each granule of sand. So keep it simple and leave the physics out of it and just simulate the effect.

For example, off the top of my head you can use 3 simple rules: Gravity: If the pixel below a "sand pixel" is empty shift that column down.

Cave In: If there is a empty space between two columns of "sand pixels" fill it in if the space below it is not empty (ie. not falling)

Pile Up: if there is empty space beside a column of "sand pixels" spread it out if the space below it is not empty.

These are just some example of rules that might work. The point is to experiment to come up with a simulation that will give the desired effect. Typically it is less work and processor intensive than modeling the physics.