get_image() gives wrong result on GradientTexture2D

[bionick7]

Godot version

4.0 beta2 (mono version)

System information

Ubuntu 22

Issue description

the get_image() command gets an image with both wrong size and wrong general look when called on GradientTexture2D.
It seams the the image is always 64x64 pixels. It depicts a different gradient with generally the same colors.

Steps to reproduce

Put the following code on a Sprite2D and put any gradient not 64x64 pixels in size into "gradient_texture"

extends Sprite2D

@export var gradient_texture: GradientTexture2D 

func _ready():
	var img = gradient_texture.get_image()
	prints(img.get_width(), img.get_height())
	texture = ImageTexture.create_from_image(img)

Minimal reproduction project

GradientTexture2DBug.zip

[timothyqiu]

Size properties are set after gradient:

godot/scene/resources/texture.cpp

Lines 2518 to 2520 in 56563ef

	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "gradient", PROPERTY_HINT_RESOURCE_TYPE, "Gradient", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_EDITOR_INSTANTIATE_OBJECT), "set_gradient", "get_gradient");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "width", PROPERTY_HINT_RANGE, "1,2048,or_greater,suffix:px"), "set_width", "get_width");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "height", PROPERTY_HINT_RANGE, "1,2048,or_greater,suffix:px"), "set_height", "get_height");

set_gradient() updates the image directly, while set_width() and set_height() defers the update:

godot/scene/resources/texture.cpp

Lines 2414 to 2418 in 56563ef

	void GradientTexture2D::set_width(int p_width) {
	ERR_FAIL_COND_MSG(p_width <= 0 || p_width > 16384, "Texture dimensions have to be within 1 to 16384 range.");
	width = p_width;
	_queue_update();
	}

So in _ready(), the image you get still uses the default 64x64 size, and there's a size update pending.

As a workaround, you can put either snippet at the beginning of _ready():

# Wait for one frame
await get_tree().process_frame

# Or something like this to trigger the image update
var g := gradient_texture.gradient
gradient_texture.gradient = null
gradient_texture.gradient = g

[Calinou]

The update is likely deferred so that the gradient isn't generated twice when both width and height are set at the same time. Otherwise, whenever the gradient uses a non-default width and height, it'd be generated twice.

We may not be able to fix this without causing this inefficiency, so I'd vote for documenting this in the class reference instead.

[knil79]

This is confirmed in 4.0.2 as well, is there already a commit for the documentation update with the work around?

[KoBeWi]

Fixed by #81137