40 lines
1.4 KiB
Plaintext
40 lines
1.4 KiB
Plaintext
/// Calculate difference between two bearings, in -180 to 180 degrees range
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pub fn angle_difference(bearing1: f64, bearing2: f64) -> f64 {
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let diff = (bearing2 - bearing1) % 360.0;
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if diff < -180.0 {
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360.0 + diff
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} else if diff > 180.0 {
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-360.0 + diff
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} else {
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diff
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_angle_difference() {
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assert_eq!(25.00, angle_difference(20.00, 45.00));
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assert_eq!(90.00, angle_difference(-45.00, 45.00));
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assert_eq!(175.00, angle_difference(-85.00, 90.00));
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assert_eq!(-175.00, angle_difference(-95.00, 90.00));
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assert_eq!(170.00, angle_difference(-45.00, 125.00));
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assert_eq!(-170.00, angle_difference(-45.00, 145.00));
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approx_eq(-118.1184, angle_difference(29.4803, -88.6381));
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approx_eq(-80.7109, angle_difference(-78.3251 , -159.036));
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approx_eq(-139.5832, angle_difference(-70099.74233810938, 29840.67437876723));
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approx_eq(-72.3439, angle_difference(-165313.6666297357, 33693.9894517456));
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approx_eq(-161.5029, angle_difference(1174.8380510598456, -154146.66490124757));
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approx_eq(37.2988, angle_difference(60175.77306795546, 42213.07192354373));
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}
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// approximate equality on floats.
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// see also https://crates.io/crates/float-cmp
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fn approx_eq(f1: f64, f2: f64) {
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assert!((f2-f1).abs() < 0.0001, "{} != {}", f1, f2)
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}
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}
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