Calculating the difference of rotation states

NameHere

13y1.6kVisual Basic .NET

Is it possible to calculate the difference of rotation states? 359 and 0 should make 1 not 359.

8 Replies

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Vulpes13y ago
Accepted answer
OK, I'm clear now :)

Try this revised version:

using System;

public struct RotationState
{
public readonly double Degrees;

public RotationState (double degrees)
{
if (degrees < 0)
{
degrees = (-degrees) % 360;
degrees = 360 - degrees;
}
Degrees = degrees % 360;
}

public static double operator -(RotationState r1, RotationState r2)
{
double diff1 = r1.Degrees - r2.Degrees;
if (diff1 < 0) diff1 += 360;
double diff2 = r2.Degrees - r1.Degrees;
if (diff2 < 0) diff2 += 360;
return Math.Min(diff1, diff2);
}
}

class Test
{
static void Main()
{
var rs1 = new RotationState(0);
var rs2 = new RotationState(359);
double diff = rs1 - rs2;
Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff);
rs1 = new RotationState(-12);
rs2 = new RotationState(7);
diff = rs1 - rs2;
Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff);
Console.ReadKey();
}
}

The output should be:

The difference between 0 and 359 degrees is 1
The difference between 348 and 7 degrees is 19
NameHere13y ago
Ok thank you that worked :)
NameHere13y ago
I want the shortest distance between the rotations (sorry couldn't find the right description for that what I want)
Vulpes13y ago
The difference between -12 and 7 is in fact 341.

-12 is treated as 348, less 7, equals 341.

Anyway, if these are not the answers you're expecting, then you should make it clear what you do want.
NameHere13y ago
The difference of -12 and 7 is 340, that's not right...
Vulpes13y ago
Are you sure you've copied it correctly?

When I ran it, the output was:

The difference between 0 and 359 degrees is 1

Of course if you reverse the operands so that you're subtracting 0 from 359 the result will be 359 because the subtraction method always works in a clockwise direction.
NameHere13y ago
Doesn't work. I'm getting 354 as difference and that shouldn't be possible.
Vulpes13y ago
It sounds like a good use for operator overloading:

using System;

public struct RotationState
{
public readonly double Degrees;

public RotationState (double degrees)
{
if (degrees < 0)
{
degrees = (-degrees) % 360;
degrees = 360 - degrees;
}
Degrees = degrees % 360;
}

public static double operator -(RotationState r1, RotationState r2)
{
double diff = r1.Degrees - r2.Degrees;
if (diff < 0) diff += 360;
return diff;
}
}

class Test
{
static void Main()
{
var rs1 = new RotationState(0);
var rs2 = new RotationState(359);
double diff = rs1 - rs2;
Console.WriteLine("The difference between {0} and {1} degrees is {2}", rs1.Degrees, rs2.Degrees, diff);
Console.ReadKey();
}
}