Force Javascript array to Float32

Question

I'm working with WebGL, so I need Float32Arrays all the time. Is there a way to force an array to be a Float32Array? I tried this:

var cubeVertices = new Float32Array(3 * 4 * 6);
cubeVertices = [
   /* Vertices */
];

But this appears to change the type to a Float64Array, since I can't use it with WebGL, but it works when I do a new Float32Array(cubeVertices). I don't really want to use the new Float32Array command all the time, since it allocates memory that is of no use, because I don't need several copies of my data.

So is there a way of creating a Float32Array without having two arrays, where one is never used again?

Akxe · Accepted Answer · 2020-06-10 13:26:32Z

1

There are only 3 ways to create the actual Float32Array:

new Float32Array(length)
TypedArray.from(source[, mapFn[, thisArg]]) source
TypedArray.of(element0[, element1[, ...[, elementN]]]) source

answered Jun 10, 2020 at 13:26

Akxe

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innis · Accepted Answer · 2020-06-10 13:27:21Z

0

You can do

Float32Array.from(yourArray);

The from method converts Array-like objects to Float32Array and is available for other Array types on javascript, like Array, Float32Array or Int16Array.

You can read more about this on the "Indexed Collections" of the following URL: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects

answered Jun 10, 2020 at 13:27

innis

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3 Comments

user11914177 Over a year ago

I edited the question, so that it becomes more clearer, that I don't want to just form a new array form an old one

innis Over a year ago

have you tried cubeVertices = Float32Array.from(cubeVertices) after creating the array?

user11914177 Over a year ago

But thats also useless, it just creates a new array

juzraai · Accepted Answer · 2020-06-10 13:30:03Z

0

I think this will be correct for you.

var num=[6676.88,8878.99.....];
var floatVal=num.map(function(value){
     return Math.fround(value);
});
console.log(floatVal);

edited Jun 10, 2020 at 13:30

juzraai

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answered Jun 10, 2020 at 13:25

Shantanu Sharma

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1 Comment

user11914177 Over a year ago

But that doesn't solve the problem, it just creates an other array and by that point I can just do a new Float32Array

user11914177 · Accepted Answer · 2020-06-11 14:03:34Z

0

So I kind of created my own solution out of these answers, so that there aren't two arrays wasting memory. I use the Float32Array.from function and create a local array there that should be deleted after that line, so my code looks like this:

var cubeVertices = Float32Array.from(
  [
     0.5, -0.5, -0.5,
    -0.5, -0.5, -0.5,
     0.5,  0.5, -0.5,
    -0.5,  0.5, -0.5
  ]
);

Thanks to Akxe, using Float32Array.of would be even better, but it is not very widely supported.

edited Jun 11, 2020 at 14:03

answered Jun 10, 2020 at 13:40

user11914177

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4 Comments

Akxe Over a year ago

Not the best of solutions... Float32Array.of(0.5, -0.5, -0.5, -0.5, -0.5, -0.5); would work better

user11914177 Over a year ago

@Akxe what does it change?

user11914177 Over a year ago

@Akxe also of is not supported by Safari, which is an important browser

Akxe Over a year ago

It would prevent create the intermediate array... If you know the length upfront why don't you want to use the normal constructor? It will work best. PS: Really sorry to hear you need Safari

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