The code to create d3d11 structured buffer :

	D3D11_BUFFER_DESC desc;
	desc.ByteWidth = _count * _structSize;
	if (_type == StructType::Struct)
	{
		desc.MiscFlags = D3D11_RESOURCE_MISC_BUFFER_STRUCTURED;
	}
	else
	{
		desc.MiscFlags = 0;
	}
	desc.StructureByteStride = _structSize;
	desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
	if (_dynamic)
	{
		desc.Usage = D3D11_USAGE_DEFAULT;  
		desc.CPUAccessFlags = 0;  
	}
	else
	{
		desc.Usage = D3D11_USAGE_IMMUTABLE;
		desc.CPUAccessFlags = 0;
	}
	if (FAILED(getDevice()->CreateBuffer(&desc, NULL, &_object)))
	{
		return false;
	}

	D3D11_SHADER_RESOURCE_VIEW_DESC resourceViewDesc;
	memset(&resourceViewDesc, 0, sizeof(resourceViewDesc));

	if(_type == StructType::Float)
		resourceViewDesc.Format = DXGI_FORMAT_R32_FLOAT;
	else if (_type == StructType::Float2)
		resourceViewDesc.Format = DXGI_FORMAT_R32G32_FLOAT;
	else if (_type == StructType::Float3)
		resourceViewDesc.Format = DXGI_FORMAT_R32G32B32_FLOAT;
	else if (_type == StructType::Float4)
		resourceViewDesc.Format = DXGI_FORMAT_R32G32B32A32_FLOAT;
	else
		resourceViewDesc.Format = DXGI_FORMAT_UNKNOWN;
	resourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_BUFFER;
	resourceViewDesc.Buffer.ElementOffset = 0;
	resourceViewDesc.Buffer.NumElements = _count;

	
	ID3D11Resource* viewObject = _object;
	auto hr = getDevice()->CreateShaderResourceView(viewObject, &resourceViewDesc,
		&_shaderResourceView);
	if (FAILED(hr))
	{
		return false;
	}

I've created a float type structured buffer.

The source data is a float array, I update the buffer from array[startIndex] to array[endIndex - 1].

The code to update buffer :

	
bool setData(int startIndex, int endIndex, const void* data)
{
  if (!data)
		return false;
	D3D11_BOX destBox;
	destBox.left = startIndex * _structSize;
	destBox.right = endIndex * _structSize;
	destBox.top = 0;
	destBox.bottom = 1;
	destBox.front = 0;
	destBox.back = 1;

	getContext()->UpdateSubresource(_object, 0, &destBox, 
		data,
		_count * _structSize,
		0);
}

The final result is that the data is not smooth, then I change the code of setData

destBox.left = startIndex ;
    destBox.right = endIndex ;

Then, the result looks smooth, but with some data missed !!!!

Don't know why..

For UpdateSubresource the "left" and "right" members of the box should be offsets in bytes when updating a buffer resource, so the code that you posted for your setData function looks correct. What exactly do you mean when you say that "the data is not smooth"?

5 hours ago, MJP said:

For UpdateSubresource the "left" and "right" members of the box should be offsets in bytes when updating a buffer resource, so the code that you posted for your setData function looks correct. What exactly do you mean when you say that "the data is not smooth"?

solved, there's nothing missed, thank you !!!