Vector3.CalculateAngle() may return NaN
Posted Sunday, 10 July, 2011 - 19:31 by Arcane.Artist| Project: | The Open Toolkit library |
| Version: | 1.0-2010-10-06 |
| Component: | Code |
| Category: | bug report |
| Priority: | normal |
| Assigned: | Unassigned |
| Status: | open |
Description
// source Vector3.cs public static float CalculateAngle(Vector3 first, Vector3 second) { return (float)System.Math.Acos((Vector3.Dot(first, second)) / (first.Length * second.Length)); }
I've isolated my problem down to Vector3.CalculateAngle. If the differences between the value are small enough, Vector3.Dot(first, second) / (first.Length * second.Length) can result in a value greater then 1.0, causing Acos to return NaN. Can easily be fixed with below.
public static float CalculateAngle(Vector3 first, Vector3 second) { return (float)System.Math.Acos(Math.Min((Vector3.Dot(first, second)) / (first.Length * second.Length), 1.0f)); }