When to use Float32Array instead of Array in JavaScript
I would assume that the glMatrix library uses Float32Array because it is primarily used in WebGL-applications, where matrices are represented as Float32Arrays (http://www.khronos.org/registry/webgl/specs/1.0/#5.14.10).
I emailed the developer of glMatrix
and my answer below includes his comments (points 2 & 3):
Creating a new object is generally quicker with
Array
thanFloat32Array
. The gain is significant for small arrays, but is less (environment dependent) with larger arrays.Accessing data from a
TypedArray
(eg.Float32Array
) is often faster than from a normal array, which means that most array operations (aside from creating a new object) are faster with TypedArrays.As also stated by @emidander,
glMatrix
was developed primarily for WebGL, which requires that vectors and matrices be passed asFloat32Array
. So, for a WebGL application, the potentially costly conversion fromArray
toFloat32Array
would need to be included in any performance measurement.
So, not surprisingly, the best choice is application dependent:
If arrays are generally small, and/or number of operations on them is low so that the constructor time is a significant proportion of the array's lifespan, use
Array
.If code readability is as important as performance, then use
Array
(i.e. use[]
, instead of a constructor).If arrays are very large and/or are used for many operations, then use a TypedArray.
For WebGL applications (or other applications that would otherwise require a type conversion), use
Float32Array
(or otherTypedArray
).