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Modified Atan2 Errors
http://www.robotc.net/forums/viewtopic.php?f=1&t=4969
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Author:  recondelta090 [ Wed Oct 10, 2012 10:44 pm ]
Post subject:  Modified Atan2 Errors

I am working on using the position of the joystick to calculate an angle between 0 to 360 or -180 to 180 and the built in atan2 function doesn't do that. I have a modified Atan2 code that displayed a value between 0 to 360 before RobotC 3.50 but now I get the following errors.
Code:
#define yDirection (joystick.joy1_y1)
#define xDirection (joystick.joy1_x1)
float angle = 0.0
short x = xDirection, y = yDirection;

short vectorAngle = angle;

void getJoystickVector()
{
  x = -xDirection; y = yDirection;
    angle = x == 0 && y > 0 ? PI/2 :(
            x == 0 && y < 0 ? 3*PI/2 :(
            x >= 0 && y == 0 ? 0 :(
            x > 0 && y > 0 ? atan(y*1.0/x) :(     **Error**:Invalid numeric type (float, string) for assignment to byte variable
            y >= 0 ? atan(y*1.0/x) + PI :(          **Error**:Invalid numeric type (float, string) for assignment to byte variable
            y < 0 && x > 0 ? atan(y*1.0/x) + 2*PI :
                    atan(y*1.0/x) + PI)))));
}

Author:  mightor [ Thu Oct 11, 2012 3:47 am ]
Post subject:  Re: Modified Atan2 Errors

You could also just use the atan2 function in ROBOTC :)
Code:
float atan2(const float Y, const float X);

- Xander

Author:  fxlj007 [ Fri Oct 12, 2012 3:17 pm ]
Post subject:  Re: Modified Atan2 Errors

What's the difference between atan() and atan2()? Seems atan2() is a newly-added function, as it doesn't appear in the Help document?

Author:  Spiked3 [ Fri Oct 12, 2012 4:56 pm ]
Post subject:  Re: Modified Atan2 Errors

Welcome to the internet. Google is your friend; http://en.wikipedia.org/wiki/Atan2

Author:  mightor [ Sat Oct 13, 2012 3:09 am ]
Post subject:  Re: Modified Atan2 Errors

atan2 is twice as healthy as a regular atan but has fewer calories while still maintaining the same fresh flavour.

Regards,
Xander

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