Cubemaps are not oriented consistently between rendering pipelines

If you try to create a cube map from images, like the code block below, you might find that images in the cubemap are not oriented correctly: ¹

@tool
extends Node
 
const NX = preload("res://prefabs/black_hole/preprocess/nx.png")
const NY = preload("res://prefabs/black_hole/preprocess/ny.png")
const NZ = preload("res://prefabs/black_hole/preprocess/nz.png")
const PX = preload("res://prefabs/black_hole/preprocess/px.png")
const PY = preload("res://prefabs/black_hole/preprocess/py.png")
const PZ = preload("res://prefabs/black_hole/preprocess/pz.png")
 
@export var preprocess: bool = false
@export var cubemap: Cubemap
 
func _process(_delta: float) -> void:
	if preprocess:
		preprocess = false
 
		cubemap = Cubemap.new()
		cubemap.create_from_images([
			PZ.get_image(),
			NZ.get_image(),
			NX.get_image(),
			PX.get_image(),
			PY.get_image(),
			NY.get_image()
		])

You might run into this problem because cubemaps do not render the same between Compatability (which uses OpenGL) and the Forward+ (which uses Vulkan) renderers. For more information, see godotengine/godot#85440. ¹

Footnotes

1. 202404182259 ↩ ↩²