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[TeaAndBiscuits]

Hi guys,
I have a little maths question for you.

My entities move around using some basic physics in the form of

vel.x += stepSize * timeElapsed;
pos.x += vel.x;
vel.x *= friction;

NOTE : stepSize, timeElapsed and friction are effectively constant

It would be really useful to know the top speed the entity will be able to reach (roughly no need for 100% accuracy here!)

After a few beers last night my brain isn't able to deal with this today   

cheers

[BorisTheBrave]

velX before  = velX after
i.e.

velX = (velX + stepSize * timeElapsed) * friction;

Rearranging

velX = stepSize * timeElapsed * friction / ( 1 - friction)

[TeaAndBiscuits]

Thanks for the reply!

But can you explain this a little bit more please? My brain still isn't working, time for a brew I think 

[TeaAndBiscuits]

EUREKA!

I get it now. Coffee for the win

Many thanks

[PleasingFungus]

...shouldn't the second line (of the original code) be "pos.x += vel.x * timeElapsed"?

[TeaAndBiscuits]

Really?
Velocity is a product of distance and time so then multiplying the velocity by time wouldn't work.

Also Velocity accumulates over many frames so to then multiply the total velocity by the time step would make funky things happen.

[BorisTheBrave]

no, cavalcade is right. velocity = distance / time.

[bateleur]

To put things in more intuitive terms, if you run for twice as long wouldn't you expect to travel twice as far?

[TeaAndBiscuits]

WOOPS! 

Got myself into a right pickle. Thanks for the correction, looks like I need to fix this then. Damn.