Question

I would like to store the x y and z co-ords for some objects for a game but I can’t find a built in class like Point. Is there a nice standard class I could add in and use that would handle distance between points/bearings from one object to another etc?

Answer 1

Having recently done some vector mapping (including z / 3D), and seeing your Android tag, I recommend rolling your own.

The reasons are many:

• You can customize to meet your specific precision / memory / performance constraints.
• If multi threaded, you can make your class immutable and thread-safe
• I.e. If memory constrained you can store all three dimensions in an int or long
• If cpu constrained you can use plain-old separate numbers
• If GC / Garbage constrained, you can recycle and pool instances (mutable)

In the end, most of these primitives are quite simple to write, test, etc. The main methods you’ll need to write (beyond boilerplate constructor/get/set/…)
– Distance
– Dot product
– Unitize (make length == 1 for various math ops)
– And I’ve used DistanceSquared in the past for comparison functions… This removes the sqrt operator from most distance methods, while computing a relative distance useful enough for comparing point distances etc.