Drawing using Integer/Float

[Steve Elliott]

@ AGK
What happens if you do not use round() (as this is a custom command) but just cast the float to an integer?

Same thing.

[Derron]

Then this would be a bug imho. Or at least something unexpected.


Bye
Ron

[Steve Elliott]

If I draw a black rect-image on a white background using floats then I will see some grayish border around the rectangle when using SDL

I always thought SDL only worked with integers.

[Steve Elliott]

@ AGK
What happens if you do not use round() (as this is a custom command) but just cast the float to an integer?

Same thing.

Then this would be a bug imho. Or at least something unexpected.

Not really, like I said anything x.5 and above is correctly rounded up, so 5.5 *is* 6 if you round it up, 5.1 *is* 5 if you round down.  The C++/Blitz Max casting are working at a lower level there.   AGK doesn't have casting as far as I know, you can just pass a float into an integer variable and it will round up or down as I just wrote.

[Qube]

AGK doesn't have casting as far as I know, you can just pass a float into an integer variable and it will round up or down as I just wrote.

Yup, assigning a float value to an integer will just round up / down accordingly. Apart from that there are the commands Round, Trunc, Floor and Ceil.

[Steve Elliott]

Apart from that there are the commands Round, Trunc, Floor and Ceil.

Aha!  Trunc is the equivalent of casting (and works).

Code Select Expand


fnum As Float
num As Integer

fnum = 2.1 + 0.5      // rounds down eg2)  2.9 + 0.5 rounds up - prints 3
num = Trunc( fnum )
Print( num )          // prints 2


[Derron]

So it seem we kind of gave you some AGK experience points. Level up?


@ float to integer
if it rounds without telling you then I think it is unexpected behaviour. It might be some convenience thing but rounding rules differ according to who you ask (economics, programming, ...).
Nonetheless - we found "trunc" and so you can have your "+0.5" thing working - while we also found out that it seems to not be needed in all cases as you can render at floating point positions.


@ SDL
Yes it might be able to only handle integer positions - but if you just use SDL as "graphics basement" and put your own GL commands on top then you can of course do how you like (this is how Brucey handled in in SDL.mod I think).


bye
Ron

[Steve Elliott]

So it seem we kind of gave you some AGK experience points. Level up?

lol yes AGK was completely new to me, now I'm picking up the language bit by bit.

@ SDL
Yes it might be able to only handle integer positions - but if you just use SDL as "graphics basement" and put your own GL commands on top then you can of course do how you like (this is how Brucey handled in in SDL.mod I think).

Ah, so I was right.  Thanks to you and Qube for explaining how it was achieved in SDL. I've some experience with SDL/C++ but never liked that limitation.