Make games launch faster by loading resources in the background

[D8H]

Blocked by

• Upgrade Pixi to 7.3.0 #5633

Changes

• The 1st loading screen only appear while the 1st scene is loading.
• The other scenes are downloaded in background.
• Big games may not have the time to load completely while users navigate in the menu in this case a 2nd loading screen may happens while the level finish to load.
• New conditions and actions allow to make a scene display a custom loading screen.
  • An action allows to prioritize a scene to be downloaded?
  • A condition and an expression allow to follow the loading progress.
• 3D games with a lot of animated models may display a quick loading screen while they are parsed to avoid any frame skipping during the background loading.

Documentation

• [Resource loading] Add a page about resource loading GDevelopApp/GDevelop-documentation#139

[4ian]

Shuld we move these into a "Loading" group?

[D8H]

There is only one action, it would look odd, unless if it's for hiding it, but it would make an extra click for users without saving any space in the list.

[D8H]

Maybe we could explain in the description that most games don't need to worry about it?

[4ian]

Yes please. Use a Hint in newIDE/app/src/Hints/index.js to do so. Thanks!
"For most games, the default, automatic loading of resources will be sufficient. You can use this action to ensure you start loading a specific scene. This is helpful if you want to use the expressions related to loading to display a progress/loading bar."

[4ian]

We can't use use ResourcesInUseHelper?

[D8H]

Do you mean moving the features in this class?

[4ian]

I'm not sure but I had the impression that we already had a class that was made to list the resources, so I was wondering if this new class could indeed be merged with the existing one?

[D8H]

ResourcesInUseHelper search resources by type on the whole project when the new one is searching resources per scene no matter the type. It's very likely that we will want to cross these searches at some point, but we should leave it for later.
I should rename the new class SceneResourcesFinder and move it in the same folder as ResourcesInUseHelper.

[4ian]

For GDevelop users, would it be simpler to return a percentage?

Suggested change

	export const getSceneLoadingProgress = (
	export const getSceneLoadingProgressPercent = (

[D8H]

A percentage is a format not a value 0.1 can be formatted "10%". Values for 0 to 1 is easier to use because you don't have to divided by 100 every time you use it, for instance to calculate the position of the right side of the bar.

It would lead to aberration like "10,000.0%" if users use an extension to format the number.

[4ian]

Ok, fine to keep it then, even if we have percentages in other part of the app (sounds volume, etc...).

[4ian]

The naming is a bit outdated but let's keep it for compatibility

[4ian]

Let's go!