AtanD troubles

[Kamac]

Hi.

So i am having troubles with rotating by bitmap at, i am using atand.

rot3 = ATanD((posx - pos2x)/(posy - pos2y)*-1)

Everything works fine when posy is bigger than pos2y, but when it is otherwise, AtanD won't return me a value in degrees, that would rotate my sprite down.


It sounds kinda weird, but it returns values only that can rotate in up. So it can be rotated:

_\|/_

in all these directions, but not opposite

 

[thedesolatesoul]

Firstly, I think it is (y/x) not (x/y) as in your code.
i.e.

rot3 = ATanD((posy - pos2y)/(posx - pos2x)*-1)

And yes sometimes it does that...i saw a workaround in klaus' code somewhere.

when posy-pos2y = 0, AtanD will return zero. Instead of either 0 or 180.

So,

if posy-pos2y = 0 then
     if posx-pos2x < 0 then
           rot3 = 180
     else
           rot3 = 0
     end if
else
     rot3 = ATanD((posy - pos2y)/(posx - pos2x)*-1)
end if

I hope this works...havent tried it.

 

[Kamac]

I've switched X with Y so it is (y)/(x) now, but now it can rotate only left or right :BangHead:.

Your code doesn't works .


EDIT@

I've added:

rot3 = rot3 + 180

So now it's rotated properly, but if i would have dynamic objects, it would be harder :|

 

[thedesolatesoul]

This was Klaus's function:

Sub CalcAngle(x As Float, y As Float) As Float
   Dim a As Float
   
   If x - x0 = 0 Then
      a = 90
   Else
      a = ATanD((y - y0)/(x - x0))
   End If
   If x - x0 < 0 Then
      a = a + 180
   End If
   Return a
End Sub

I remember is worked beautifully.

 

[Kamac]

Hmph.

Could you provide some example of use Klaus's function in rotation? :sign0104:

 

[thedesolatesoul]

Why dont you have a look at: http://www.b4x.com/forum/basic4android-updates-questions/11186-rotation-moving-2.html#post62578

 

[Kamac]

:signOops:


Didn't notice that one :BangHead: