[Native SDK] I got a runtime error "Buffer Validation Cannot create buffer of zero length."

fullc0de

Hello

While testing several models for our app, we encountered the following error during the initialization of model:

-[MTLDebugDevice newBufferWithLength:options:]:642: failed assertion `Buffer Validation
Cannot create buffer of zero length.`
Coming from the lines:
(CubismComandBuffer_Metal)
Line 89
_vertices = [device newBufferWithLength:_vbStride * count
options:MTLResourceStorageModeShared];
(CubismRenderer_Metal)
Line 1310
const csmInt32 drawableVertexCount = model->GetDrawableVertexCount(i);
Line 1317
_drawableDrawCommandBuffer[i]->CreateVertexBuffer(device, vertexSize, drawableVertexCount);



We tried the models in frameworks CubismSdkForNative-4.r.7 and CubismSdkForNative-5.r.1-beta.3 both in the demo app and in our app and both resulted in the mentioned error. (Simulator and real device)

The target model can be downloaded via https://ko-fi.com/s/867102f774. It's free.

This issue is caused by value 0 from "model->GetDrawableVertexCount(i)" some value of an array on a certain index has value 0. I was wondering if it's normal that the array contains zeros sparsely. We found the workaround to return 1 instead of 0 to resolve it. That's working now, but I am afraid that it's the right approach.

As mentioned again to be clear, it occurs on the demo app for native provided by Live2D.

Thank you in advance.

Enoko(Staff)

@fullc0de

Thank you for always using our products.

I apologize for the delay in getting back to you.
We are currently investigating, so please wait for a while.
I will contact you again.

Enoko(Staff)

@fullc0de

Thank you for always using our products.

We investigated the cause of the error occurring in the SDK for Native Metal environment.

This error occurs because the path of the model's facial expression file (exp3.json) in model3.json is incorrect.
The location of exp3.json is in the exp directory, but that directory is not written in model3.json.

The SDK for Native checks whether the file path listed in the model3.json file exists regardless of the renderer, so an error occurs because the expression file with the wrong path cannot be loaded.

In fact, if you ignore the loading of exp3.json in model3.json, the model will be able to be drawn correctly, so correct the file path or ignore the loading of exp3.json. It works.

We use machine translation. If there is anything that is difficult to understand, please feel free to let me know.
Best regards.