Am I using Atlas Correctly?

General
1

New to Godot - working on my first card game. I’ve been testing my game on lower-tier Android devices and I have come across some serious performance issues. In researching I came across the recommendation of using an Atlas for my images. I want to use an Atlas for my 50+ card images, but is this the most efficient way to do so?

var atlas_image = Image.new()
atlas_image.load("res://Assets/Atlas/AtlasCards.png")

Card #1:

var card_1_image: AtlasTexture = AtlasTexture.new()
var card_1_texture = ImageTexture.create_from_image(atlas_image)
card_1_image.atlas = card_1_texture
var card_1_region = Rect2(Vector2(0,0), Vector2(100, 150))
card_1_image.region = card_1_region

Card #2:

var card_2_image: AtlasTexture = AtlasTexture.new()
var card_2_texture = ImageTexture.create_from_image(atlas_image)
card_2_image.atlas = card_2_texture
var card_2_region = Rect2(Vector2(100,0), Vector2(100, 150))
card_2_image.region = card_2_region

Then I assign:

%Card_1.texture = card_1_image
%Card_2.texture = card_2_image

This is supposed to increased the performance, less memory for images. However, compared to current method where I just have a single image saved in my Assets folder and make an assignment like so:

%Card_1.texture  = preload("res://Assets/image_card_one.webp")
%Card_2.texture = preload("res://Assets/image_card_two.webp")

The option to use an Atlas seems far more complicated, especially since I have to now create/use 3 variables to make an image assignment - or 100+ to make assignments for each card. So I was wondering if my above setup was correct. It works, but is it the most efficient way to make the image assignments using an Atlas? Thanks.

2

You can use one texture for the atlas image for all cards, instead of creating a new ImageTexture from an Image for each one. Since you just need an ImageTexture and not an Image to do that, I believe you can just load the file as an ImageTexture:

var atlas_image_texture = load("res://Assets/Atlas/AtlasCards.png")

[...]

card_1_image.atlas = atlas_image_texture

Creating AtlasTextures does get repetitive, which makes it a good problem to use a helper function for. Probably something like this:

const card_texture_size = Vector2(100, 150)
func make_card_texture(row: int, column: int) -> AtlasTexture:
    var texture = AtlasTexture.new()
    texture.atlas = atlas_image_texture
    texture.region = Rect2(
        Vector2(column * card_texture_size.x, row * card_texture_size.y),
        card_texture_size
    )
    return texture

So then for the assignments you’d have something like this:

%Card_1.texture = make_card_texture(0,0)
%Card_2.texture = make_card_texture(0,1)
1 Like
3

I was able to resolve my issue in another way, but this is a great answer. I’ll surely use this in the future - thank you!

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