How to use the AtlasTexture2D with Polygon2D

[ughuuu]

Godot Version

4.2.1

Question

I am using the AnimatedSprite2D to get an animation out of a AnimationFrames Resource. This resource is using a TextureAtlas. I want to make an animatable object that uses Skeleton2D node(only works with Polygon2D node).

So, I am taking an animation out of the TextureAtlas and putting it in the Polygon2D node. And now I am confused as to how it should work.

The texture atlas looks like this:

For a Polygon2D node with texture, normally, I would go in the Sprite Editor and draw out the boundaries, like this:

Problem happens when I go to the Polygons tab, it doesn’t seem to follow the uv’s I set:

Similar in game it’s rendered like that:

[ncs]

I’m having the same issue.
(In my case, I imported my textures via TexturePacker and had a plugin generate the texture atlas for me, but the end result is the same.)

Did you find a solution to the issue?

[ughuuu]

Nope, just gave up on this for now.

[ncs]

Ah, that’s unfortunate.
Thanks for the quick response though!

[ughuuu]

Looking back at this, probably it could be solved with a shader. I guess thats how the shader does it probably. Eg. attach a shader to the polygon, read input from the texture atlas and change the uv to show the correct one.

[Awtumn]

Yup.
Here’s what I used. It’s still hard-codey. Can be made better:
Shader:

shader_type canvas_item;
uniform vec2 uv_offset = vec2(0, 0); 
uniform vec2 uv_scale = vec2(0, 0); 

void fragment() {
    vec2 sampled_uv = uv_offset + (UV * uv_scale);
    vec4 color = texture(TEXTURE, sampled_uv);

    COLOR = color; // Output the final color
}

gdscript.
→ on the polygon2d
→ copy the rect x,y,w,h into Sprite Region Pixels
→ Atlas Size = size of the original image

extends Polygon2D

@export var atlas_size = Vector2(600,700)
@export var sprite_region_pixels: Rect2 = Rect2(247.0, 129.0, 73.0, 204.0):
	set(value):
		sprite_region_pixels = value
		_update_shader_params()

var _shader_material: ShaderMaterial

func _ready()->void:
	
	if not material is ShaderMaterial:
		push_warning("Polygon2D material is not a ShaderMaterial. Cannot set atlas rect.")
		return
	
	_shader_material = material as ShaderMaterial
	_update_shader_params()

func _update_shader_params():
	if not _shader_material or not texture:
		return
	
	if atlas_size.x == 0 or atlas_size.y == 0:
		push_warning("Atlas texture has zero size. Cannot calculate UVs.")
		return
	var uv_offset = Vector2(
		sprite_region_pixels.position.x / atlas_size.x,
		sprite_region_pixels.position.y / atlas_size.y
	)
	var uv_scale = Vector2(
		sprite_region_pixels.size.x / atlas_size.x,
		sprite_region_pixels.size.y / atlas_size.y
	)
	print("uv_offset ", uv_offset)
	print("uv_scale ", uv_scale)
	_shader_material.set_shader_parameter("uv_offset", uv_offset)
	_shader_material.set_shader_parameter("uv_scale", uv_scale)