Seeing that TickDuration is being deprecated and that I should use Duration instead, I faced a problem. I need to get total seconds like a float. Using .total!"seconds" returns a long and if the duration is less than 1 second I get 0. My question is whats the right way to do it. Because I saw that TickDuration has a to!("seconds", float) method, but Duration doesn't have one. I can convert Duration to TickDuration and call to but seeing that its deprecated makes me think there is a better way.

On Sunday, 17 January 2016 at 14:43:26 UTC, Borislav Kosharov wrote:
> Seeing that TickDuration is being deprecated and that I should use Duration instead, I faced a problem. I need to get total seconds like a float. Using .total!"seconds" returns a long and if the duration is less than 1 second I get 0. My question is whats the right way to do it. Because I saw that TickDuration has a to!("seconds", float) method, but Duration doesn't have one. I can convert Duration to TickDuration and call to but seeing that its deprecated makes me think there is a better way.

Why not just use a smaller granularity for Duration.total and convert the result?

duration.total!"nsecs" / cast(float) 1e9

On Sunday, 17 January 2016 at 18:57:13 UTC, biozic wrote:
> On Sunday, 17 January 2016 at 14:43:26 UTC, Borislav Kosharov wrote:
>> Seeing that TickDuration is being deprecated and that I should use Duration instead, I faced a problem. I need to get total seconds like a float. Using .total!"seconds" returns a long and if the duration is less than 1 second I get 0. My question is whats the right way to do it. Because I saw that TickDuration has a to!("seconds", float) method, but Duration doesn't have one. I can convert Duration to TickDuration and call to but seeing that its deprecated makes me think there is a better way.
>
> Why not just use a smaller granularity for Duration.total and convert the result?
>
> duration.total!"nsecs" / cast(float) 1e9

Yea I could do that, but its not intuitive to get a total of one magnitude to just convert it to another. My question is why doesn't `to!` accept Duration.

On Sunday, January 17, 2016 14:43:26 Borislav Kosharov via Digitalmars-d-learn wrote:
> Seeing that TickDuration is being deprecated and that I should use Duration instead, I faced a problem. I need to get total seconds like a float. Using .total!"seconds" returns a long and if the duration is less than 1 second I get 0. My question is whats the right way to do it. Because I saw that TickDuration has a to!("seconds", float) method, but Duration doesn't have one. I can convert Duration to TickDuration and call to but seeing that its deprecated makes me think there is a better way.

In general, using floating point values with time is an incredibly bad idea. It can certainly make sense when printing stuff out, but using it in calculations is just asking for trouble given all of the unnecessary imprecision that it adds. So, Duration does not directly support floating point values at all, and that's very much on purpose. I'd strongly argue that the fact that TickDuration does was a mistake.

So, if you're doing floating point calculations with time, I'd strongly urge you to rethink your code. And if you're just trying to print out the a duration as a floating point value, because it's nice to view that way, then that's fine, but you'll need to do the conversion yourself. And it's not that hard. It just isn't handed to you directly, because aside from printing, code really shouldn't be using floating point values for time. e.g.

string toFloatingSeconds(Duration d)
{
    import std.conv;
    enum hnsecsPerSecond = convert!("seconds", "hnsecs")(1);
    auto s = d.split!("seconds", "hnsecs")();
    return to!string(s.seconds + cast(real)(s.hnsecs) / hnsecsPerSecond);
}

And yes, that's a bit more of a pain than using to!("seconds", float) with TickDuration, but it's also the sort of thing that most code really shouldn't be doing. So, adding that functionality to Duration would just encourage folks to write buggy code.

- Jonathan M Davis

On Monday, 18 January 2016 at 12:46:31 UTC, Jonathan M Davis wrote:
> In general, using floating point values with time is an incredibly bad idea. It can certainly make sense when printing stuff out, but using it in calculations is just asking for trouble given all of the unnecessary imprecision that it adds. So, Duration does not directly support floating point values at all, and that's very much on purpose. I'd strongly argue that the fact that TickDuration does was a mistake.
>
> So, if you're doing floating point calculations with time, I'd strongly urge you to rethink your code. And if you're just trying to print out the a duration as a floating point value, because it's nice to view that way, then that's fine, but you'll need to do the conversion yourself. And it's not that hard. It just isn't handed to you directly, because aside from printing, code really shouldn't be using floating point values for time. e.g.
>
> string toFloatingSeconds(Duration d)
> {
>     import std.conv;
>     enum hnsecsPerSecond = convert!("seconds", "hnsecs")(1);
>     auto s = d.split!("seconds", "hnsecs")();
>     return to!string(s.seconds + cast(real)(s.hnsecs) / hnsecsPerSecond);
> }
>
> And yes, that's a bit more of a pain than using to!("seconds", float) with TickDuration, but it's also the sort of thing that most code really shouldn't be doing. So, adding that functionality to Duration would just encourage folks to write buggy code.
>
> - Jonathan M Davis

I want to use float time in a game where I call the update method passing the delta time as float seconds. It's more easy to multiply the dt with a speed constant meaning how much the object will move after 1 second. Such float delta time is used in many game engines and it's somewhat standart way of doing it. Also the method you wrote returns a string and I need a float to multiply it with a number.
Thanks for the reply anyway

On Tuesday, 19 January 2016 at 14:07:50 UTC, Borislav Kosharov wrote:
> On Monday, 18 January 2016 at 12:46:31 UTC, Jonathan M Davis wrote:
>> [...]
>
> I want to use float time in a game where I call the update method passing the delta time as float seconds. It's more easy to multiply the dt with a speed constant meaning how much the object will move after 1 second. Such float delta time is used in many game engines and it's somewhat standart way of doing it. Also the method you wrote returns a string and I need a float to multiply it with a number.
> Thanks for the reply anyway

Checkout out how DSFML handles this.
You simply pass around a Clock object that you can restart every frame using

clock.restart();

You then call your update function with update(Clock.getElapsedTime());
Then in each objects update(Time t) method you just get the time in whatever unit you want. Works pretty well.

http://www.dsfml.com/

On Tuesday, 19 January 2016 at 15:25:58 UTC, wobbles wrote:
> On Tuesday, 19 January 2016 at 14:07:50 UTC, Borislav Kosharov wrote:
>> On Monday, 18 January 2016 at 12:46:31 UTC, Jonathan M Davis wrote:
>>> [...]
>>
>> I want to use float time in a game where I call the update method passing the delta time as float seconds. It's more easy to multiply the dt with a speed constant meaning how much the object will move after 1 second. Such float delta time is used in many game engines and it's somewhat standart way of doing it. Also the method you wrote returns a string and I need a float to multiply it with a number.
>> Thanks for the reply anyway
>
> Checkout out how DSFML handles this.
> You simply pass around a Clock object that you can restart every frame using
>
> clock.restart();
>
> You then call your update function with update(Clock.getElapsedTime());
> Then in each objects update(Time t) method you just get the time in whatever unit you want. Works pretty well.
>
> http://www.dsfml.com/

Yes that's exactly what I'm using. But they changed it to return a Duration instead of Time and that broke my code. See the source https://github.com/Jebbs/DSFML/blob/master/src/dsfml/system/clock.d#L65

On Tuesday, January 19, 2016 14:07:50 Borislav Kosharov via Digitalmars-d-learn wrote:
> On Monday, 18 January 2016 at 12:46:31 UTC, Jonathan M Davis wrote:
> > In general, using floating point values with time is an incredibly bad idea. It can certainly make sense when printing stuff out, but using it in calculations is just asking for trouble given all of the unnecessary imprecision that it adds. So, Duration does not directly support floating point values at all, and that's very much on purpose. I'd strongly argue that the fact that TickDuration does was a mistake.
> >
> > So, if you're doing floating point calculations with time, I'd strongly urge you to rethink your code. And if you're just trying to print out the a duration as a floating point value, because it's nice to view that way, then that's fine, but you'll need to do the conversion yourself. And it's not that hard. It just isn't handed to you directly, because aside from printing, code really shouldn't be using floating point values for time. e.g.
> >
> > string toFloatingSeconds(Duration d)
> > {
> >     import std.conv;
> >     enum hnsecsPerSecond = convert!("seconds", "hnsecs")(1);
> >     auto s = d.split!("seconds", "hnsecs")();
> >     return to!string(s.seconds + cast(real)(s.hnsecs) /
> > hnsecsPerSecond);
> > }
> >
> > And yes, that's a bit more of a pain than using to!("seconds", float) with TickDuration, but it's also the sort of thing that most code really shouldn't be doing. So, adding that functionality to Duration would just encourage folks to write buggy code.
> >
> > - Jonathan M Davis
>
> I want to use float time in a game where I call the update method
> passing the delta time as float seconds. It's more easy to
> multiply the dt with a speed constant meaning how much the object
> will move after 1 second. Such float delta time is used in many
> game engines and it's somewhat standart way of doing it. Also the
> method you wrote returns a string and I need a float to multiply
> it with a number.
> Thanks for the reply anyway

Using floating point as a delta for time is inherently buggy. Depending on what you're doing, you may get away with it, but it means that error is going to creep into your timing. And the bugs introduced by using floating point like that can be quite subtle. I would strongly urge anyone using floating point values with timing like that to rework their code to use integral values. Aside from TickDuration, all of core.time and std.datetime quite carefully avoids floating point values - even functions like convClockFreq (which converts one clock frequency to another).

So, if you want to use floating point values with time stuff, that's obviously your prerogative, but Duration does not directly support it and isn't ever going to directly support it precisely because it's error-prone.

- Jonathan M Davis