godot 4 glTF runtime loader

[flobotics]

hi,
i searched alot, but can only find old github post about it. Is there a doc about the new glTF runtime loader in godot 4 ?

Is it possible to e.g. start a multiplayer-networking-game and while playing, another persons sends per e.g. email a new glTF (e.g. mesh+texture) and you want to load it into the running multiplayer-networking-game without rebuilding/reloading/redistribution ?

thx

[Calinou]

cc @fire

[fire]

I don't have a detailed answer, but here's a few minutes paragraph.

The feature is using GLTFDocument and GLTFExtensions to load glb etc. at runtime like from a buffer.

You can do it, but it's not fully optimized for runtime usage.

Will see if I can get some examples, but I'm a bit slow.

[flobotics]

ok, i will do some tests

[fire]

1. Supply a glb in a byte buffer.
2. GLTFDocument has an append_from_buffer, which will give you a GLTFState.
3. You can then pass the gltf state to generate scene.

[flobotics]

thx, i am new to gdscript.

I use the Fox.glb to have a good base ( https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Fox/glTF-Binary )

1. supply a glb in a byte buffer
   var myfox = load("res://Fox.glb") #loading should be a normal filesystem path
   var myArr = PackedByteArray()
   ??? how put the myfox in myArr ???

2. GLTFDocument has an append_from_buffer, which will give you a GLTFState.
   What is the second parameter "base_path" of append_from_buffer() ??

need to learn more GDScript

[flobotics]

i can load the fox with

var gltf := GLTFDocument.new()
var gltf_state := GLTFState.new()

var path = "C:/Users/SuperUserName/Documents/godot-workspace/godot-data/Fox.glb"
var snd_file = FileAccess.open(path, FileAccess.READ)

var fileBytes = PackedByteArray()
fileBytes = snd_file.get_buffer(snd_file.get_length())

gltf.append_from_buffer(fileBytes, "base_path?", gltf_state)

var node = gltf.generate_scene(gltf_state)
add_child(node)

I use "base_path?" as parameter and it seemed to work ?

Now testing with multiplayer networking

[fire]

For a byte buffer setting base path to "" (empty) string is fine. It's a feature to not require access to the filesystem.

[fire]

Working on the docs godotengine/godot#68933

[flobotics]

thanks for the base_path info.

still trying/working on a multiplayer network test for glTF runtime loader cross platform (i am new to godot :) )

[flobotics]

hi,
i try to spawn the Fox.glb file from a networking server and it should be displayed also on the clients.

I use https://github.com/TheGodojo/Godot-4-Networking-Demonstration-Complete as a simple test project.

In the player_character.gd script i added:

@rpc(any_peer, call_local, reliable, 1)
func spawnGlTF():
	# if we are the server (could be multiplayer.is_server() ? )
	if multiplayer.get_unique_id() == 1:
		print("spawnGlTF")
		var gltf := GLTFDocument.new()
		var gltf_state := GLTFState.new()

		var path = "C:/Users/SuperUserName/Documents/godot-workspace/godot-data/Fox.glb"
		if FileAccess.file_exists(path):
			print("File to spawn exists")
		else:
			print("File to spawn does not exist")
			return
			
		var snd_file = FileAccess.open(path, FileAccess.READ)

		var fileBytes = PackedByteArray()
		fileBytes = snd_file.get_buffer(snd_file.get_length())

		gltf.append_from_buffer(fileBytes, "base_path?", gltf_state)

		var node = gltf.generate_scene(gltf_state)
		add_child(node)	
	else:
		print("notSpawnGlTF")

and call it simply when someone clicks on the player_character

func _on_mouse_click_area_input_event(camera, event, position, normal, shape_idx):
	if event is InputEventMouseButton:
		rpc("clicked_by_player")
		rpc("spawnGlTF")

The fox is loaded as a child of the player-1, but only on the server side ? What do i wrong/miss ?

thx

[fire]

I think this is a networking problem @Faless probably knows immediately. I think it's because the scene paths don't match.

[fire]

I've been also playing with a runtime loader.

https://github.com/V-Sekai-fire/VSK_model_explorer

Reference

https://github.com/V-Sekai-fire/VSK_model_explorer/blob/b5d453cd1e193c4a5a3a2cff786a9c60afaf6204/scene/ModelExplorer.gd#L32-L52

[flobotics]

hi @fire
i tried your model exporter, but its not working. I made issue V-Sekai/TOOL_model_explorer#1