iOS app - How to use jpg/png/HEIC raw data as rng seed?

collectivenectar

I'm working on a feature for an app that I'm developing that involves shuffling an array, and I'd like to provide an option for the user to provide their own random seed for the built in shuffle() method. I've been testing it with just some random pngs still sitting in my project folder. Bear with me as I'm pretty new at programming in general, let alone godot, but this is as far as I could get(nodes here don't really matter, it's just some buttons and richtextlabels):

func _on_shufflefromimage1_pressed(): var image_1_as_image = image1.get_data() var image_1_as_pool_byte_a = image_1_as_image.data.data var image_1_hash = hash(image_1_as_pool_byte_a) $rn/randomnumber.text = str(image_1_hash) seed(image_1_hash) var deck_copy = global.deck.duplicate() deck_copy.shuffle() var deck_copy_indexed = [] for i in deck_copy: deck_copy_indexed.append(global.deck.find(i)) $sai/shuffledarrayindexes.text = str(deck_copy_indexed)

The first problem is that get_string_from_ascii returns nothing, no error, just blank. If I add print(image_1_as_pool_byte_a.get_string_from_ascii()) at the end and click (shufflefromimage1) there is no printout.

The second(potential?) problem is how would this be managed from an iOS standpoint? Different iOS versions provide different image formats. Between different iOS versions, the images produced can be jpg, png, or HEIC depending on if its a screenshot, an image capture from the camera, some even TIFF. I'm a bit of a newb at mobile development, so can this idea still work?

dotted

get_string_from_ascii(): I would say immediately that the source byte data must be ascii in the first place. It is not, it's numeric data that cannot be converted to ascii text.
image1.get_data() returns PoolByteArray
image_1_as_image.data.data you are trying access a (sub) property called ".data.data" on a PoolByteArray. PoolByteArray doesn't have a .data property
I'd recommend hashing the data of image1.get_data() with https://docs.godotengine.org/en/stable/classes/class_hashingcontext.html
on the iOS side, you are going to have to limit accepted image formats to ones supported by godot. I would recommend lossless JPEG images

Other: I would recommend that you start using typing to make your scripting life easier. The editor will catch type conflicts for you.

so for instance

var image_1_as_image = image1.get_data()

turns into

var image_1_as_image:PoolByteArray = image1.get_data()

collectivenectar

Thank you for the answer, I will definitely look into hashingcontext.

I will also study the use of typing, because you are correct in that data types have been giving me some problems, I didn't realize I was missing a useful way of preventing those problems.

It's my fault for omitting relevant information for the function, I had

onready var image1 = preload("res://are you ready button.png")

in the script before the mentioned function, so image_1.get_data() was giving me [Image:1487]

Thank you again for the thorough information, as a real beginner it helps :)

dotted

You are very welcome

Calinou

on the iOS side, you are going to have to limit accepted image formats to ones supported by godot. I would recommend lossless JPEG images

There is no such thing as lossless JPEG images :)

Godot supports WebP and PNG for lossless images – note that WebP can also be lossy depending on the encoder settings.

DaveTheCoder

If the image is being used solely as a seed for random number generation, the image format and lossiness should be irrelevant, unless you want the random sequence to be reproducible.

dotted

@Calinou

https://en.wikipedia.org/wiki/Lossless_JPEG

The only reason I suggest it, is because lossless preserves data integrity. If the image is to be edited (repeatedly) losses is very much a Good Thing. Also alternate compression values will change the seed wrt to the original, which may or may not be relevant.

I could dredge up from memory an old local SMPTE talk given by a video editor regarding the dangers of lossy compression for post production but that's two decades ago and I am becoming senile.