mikolalysenko/box-intersect

how to specify an empty box?

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looking at boxEmpty(d, box) function here https://github.com/mikolalysenko/box-intersect/blob/master/index.js#L9

I'm wondering what the format is for declaring a box empty, so that it's not included in intersection tests.

Is it simply passing an empty array [] ?

Or do we 0 out the box dimensions as in[0, 0, 0, 0] ?

It seems there are 2 cases where a box will be considered empty, and excluded from intersection tests:

  • an empty array []
  • an array where any dimension's min value is > max value. An example: assuming a 2d array, the format is [minX, minY, maxX, maxY] this array: [ 4, 2, 0, 2 ] will be considered empty because minX (4) > maxX (0)

So it seems boxEmpty() is doing all of the validity checking for a given box.