var mapping = { | |
0: { | |
0: 0 | |
, 90: -90 | |
, 180: -180 | |
, 270: 90 | |
} | |
, 90: { | |
0: 90 | |
, 90: 0 | |
, 180: -90 | |
, 270: 180 | |
} | |
, 180: { | |
0: 180 | |
, 90: 90 | |
, 180: 0 | |
, 270: -90 | |
} | |
, 270: { | |
0: -90 | |
, 90: -180 | |
, 180: 90 | |
, 270: 0 | |
} | |
} | |
module.exports = function rotator(oldRotation, newRotation) { | |
var r1 = oldRotation < 0 ? 360 + oldRotation % 360 : oldRotation % 360 | |
var r2 = newRotation < 0 ? 360 + newRotation % 360 : newRotation % 360 | |
return mapping[r1][r2] | |
} |