PureBasic Forums - English

please someone check the sin() and cos() functions in ver3.8B
it seems that there is a difference in calculating these functions in new version versus version 3.72
regards
Reza

What difference are you talking about... I'm using them in this game I'm making, and I didn't see any difference when I upgraded til 3.8 (3.79Beta)

-Lars

Me too, sin & cos all over the place and seems ok.

i used this code in my program:

pi4=atan(1)
for direction=0 to 7
x=int(cos(direction*pi4)+.5)
y=int(sin(direction*pi4)+.5)
next direction

here is the result for x in version 3.72 and 3.8b

direction 3.72 3.8b
---------- ------ ------
0 1 1
1 1 1
2 0 0
3 -1 0
4 -1 0
5 -1 0
6 0 0
7 1 1

any idea?!
regards
Reza

I don't know if 3.72 didn't use radian values, but if it didn't, just try multiplying your direction with (3.141593 / 180)...
(probably won't help you, but it's worth a shot..)

-Lars

sure atan() (or arctan()) will return result in radian in all languages.
may be the problem is in the int() function
any idea?
regards
Reza

I can't figure it out.. are you sure you're using the same formula?!
I tried your code, but it returned the 3.8 result as you wrote..

-Lars

what do you mean it returned 3.8 results?!
the problem is diferences between 3.72 results and 3.8 results

direction 0 1 2 3 4 5 6 7
3.72 1 1 0 -1 -1 -1 0 1
3.8 1 1 0 0 0 0 0 1

I got almost the same results as you did in 3.8
one number differs though..

I got the sequence: 1 1 0 0 0 0 1 1

-Lars

ok, but i wrote my program to get results like what i got from v3.72!
why formula return different result in new version?!

Dunno.. maybe ask Fred..

-Lars

1.) Make sure you declare floats as floats

when you set:

pi4=ATan(1)
x=Int(Cos(direction*pi4) + 0.5)

result: 11000011

but
when you set:

pi4.f=ATan(1)
x=Int(Cos(direction*pi4) + 0.5)

result: 11000001

2.) Use:

x=Round(Cos(direction*pi4) + 0.5, 0)

instead of

x=Int(Cos(direction*pi4) + 0.5)

to get the same result as v3.72

The Handbook says:

Int()
Returns the interger part of a float number.

Example

Result = Int(10.565) ; Will return '10'

...
so if you look at the float values the v3.72 INT(x) command didn't work right...

so there was a bug in int function (v3.72) and nothing wrong with 3.8 beta about this function, yes?
thanks
regards
Reza

You're welcome
Hope that now all works well.

yes, those are ok now.
thanks