Instancing MultiMesh with local to scene flag set throws Vulkan buffer argument error

[SdgGames]

Godot version

v4.0.beta4.official [e6751549c]

System information

Windows Server 2022, Nvidia 4080 Ti, Vulkan

Issue description

I made Minecraft using chunks made of of MultiMeshInstance3Ds. Each time a new chunk is instanced, there are errors thrown. It turns out, the "Local To Scene" flag in the MultiMesh resource was causing the error. This project was a convert from Godot 3.5.1. The issue was not present in that version, it appeared after upgrading.

Error output from reproduction project below.

E 0:00:00:0780   _ready: Buffer argument is not a valid buffer of any type.
  <C++ Error>    Method/function failed. Returning: ERR_INVALID_PARAMETER
  <C++ Source>   drivers/vulkan/rendering_device_vulkan.cpp:6311 @ buffer_update()
  <Stack Trace>  Game.gd:7 @ _ready()

Despite printing an error, everything does seem to be working, I can use the multimesh that is created.

Steps to reproduce

Create a MultiMeshInstance3D with a MultiMesh and Mesh resource. Set the Local To Scene flag as shown below:

Save the scene. Load the scene resource from another scene, then call multiMeshScene.instantiate()

A rendering error will be thrown.

Minimal reproduction project

Multimesh.zip

[Lippanon]

Still present in v4.0.beta.custom_build [2a04b18d3]

E 0:00:01:0175   _ready: Buffer argument is not a valid buffer of any type.
  <C++ Error>    Method/function failed. Returning: ERR_INVALID_PARAMETER
  <C++ Source>   drivers\vulkan\rendering_device_vulkan.cpp:5856 @ RenderingDeviceVulkan::buffer_update()
  <Stack Trace>  Game.gd:7 @ _ready()

[Swarkin]

Still present in v4.0.rc5.official [6296b4600] // Edit: 4.0.stable as well

E 0:00:01:0109   Load.gd:36 @ _process(): Buffer argument is not a valid buffer of any type.
  <C++ Error>    Method/function failed. Returning: ERR_INVALID_PARAMETER
  <C++ Source>   drivers/vulkan/rendering_device_vulkan.cpp:5857 @ buffer_update()
  <Stack Trace>  Load.gd:36 @ _process()

[rmvermeulen]

v4.0.stable.mono.official [92bee43ad] I see the same issue, and it doesn't seem to matter if it's created from a saved tscn/tres file and/or duplicated afterwards. Even if I create the MultiMesh resource and node 'manually' from code this error pops up whenever it's added to the scene.

[SamsPepper1]

I get this same error message in v4.0.1.stable.official when duplicating a multimesh with an instance count of 0, as well as a second when the multimesh is set as 'local to scene' (but only when the multimesh has instancecount of 0).

[this error only shows upo when 'local to scene' is set AND instance count is 0]

E 0:00:00:0761   buffer_update: Buffer argument is not a valid buffer of any type.
  <C++ Error>    Method/function failed. Returning: ERR_INVALID_PARAMETER
  <C++ Source>   drivers/vulkan/rendering_device_vulkan.cpp:5857 @ buffer_update()

[when instance count is set to 0]

E 0:00:00:0769   Test_Multimesh_Buffer_Error.gd:6 @ _ready(): Buffer argument is not a valid buffer of any type.
  <C++ Error>    Method/function failed. Returning: ERR_INVALID_PARAMETER
  <C++ Source>   drivers/vulkan/rendering_device_vulkan.cpp:5857 @ buffer_update()
  <Stack Trace>  Test_Multimesh_Buffer_Error.gd:6 @ _ready()

It's easy enough to work around by making sure instance count is above 0, but there shouold probably be a check before vulcan tries to update a non existant buffer. I tried digging to work out where this check could be but made no headway.

Will happily make this a new issue if folk think it requires it.

[ironstrasza]

In my case, I need to instance hundreds of local to scene MultiMeshes and this really slows down the engine (150+ instances, and I have to wait up to 15-20 seconds for the engine to throw an error for each of them). After that, everything works fine.

If you can raise an issue for them, it would be much appreciated @SamsPepper1

[caimantilla]

Just saying, while the error is annoying in Vulkan, it crashes the whole program when using the OpenGL ES Compatibility renderer. It happens whether duplicating in code or using local_to_scene, so the only option is to create a new MultiMesh in code.

ERROR: GL ERROR: Source: OpenGL Type: Error     ID: 1282        Severity: High  Message: GL_INVALID_OPERATION error generated. Target buffer must be bound.
   at: _gl_debug_print (drivers/gles3/rasterizer_gles3.cpp:168)

[fracteed]

I am just running into error this in 4.1.1. My multimeshes are working correctly but each one gets this error on creation.

I am setting the instance count with gdscript and in general there is a lot of weirdness with using a multimesh from an instanced scene. But they do render correctly so far. Every time I change something in the scene with the multimesh, I have to add in back to the master scene, otherwise the changes don't update.

[fracteed]

@SamsPepper1 I had also tried this tactic, but had even more issues with it. I have it on a value above 0 and then in the ready method try to change the instance count and get the error "Condition instance_count > 0 is true". It also doesn't increase the instance count correctly, so the buffer size is incorrect.

I seem to only be able to dynamically change the instance count in ready if it is on zero to start with. Note, that 3.x didn't exhibit these issues.

[NatGazer]

Still present in 4.2 rc2 official

And yes, the project silently crashes when it's in compatibility mode. This issue should be given more attention than what it's getting

EDIT: The easiest way I found to overcome this problem is to not store the multimesh but only the mesh itself. Then you can do something like this:

var multimesh_mesh_inst : Mesh = preload("YOUR MESH PATH")

func _ready() -> void:
  #Setup multimesh
  var multimesh : Multimesh = MultiMesh.new()
  multimesh.transform_format = MultiMesh.TRANSFORM_3D
  multimesh.use_colors = true
  multimesh.instance_count = 0
  multimesh.mesh = multimesh_mesh_inst
  
  #Setup MultimeshInstance
  var multiMeshInstance : MultiMeshInstance3D = MultiMeshInstance3D.new()
  multiMeshInstance.multimesh = multimesh
  add_child.call_deferred(multiMeshInstance)