Method create

3rdparty/bgfx/src/renderer_d3d12.cpp:3807–3830

	}

	void ScratchBufferD3D12::create(uint32_t _size, uint32_t _maxDescriptors)
	{
		m_size = _size;

		ID3D12Device* device = s_renderD3D12->m_device;
		m_incrementSize = device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV);

		D3D12_DESCRIPTOR_HEAP_DESC desc;
		desc.NumDescriptors = _maxDescriptors;
		desc.Type     = D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV;
		desc.Flags    = D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE;
		desc.NodeMask = 1;
		DX_CHECK(device->CreateDescriptorHeap(&desc
			, IID_ID3D12DescriptorHeap
			, (void**)&m_heap
			) );

		m_upload = createCommittedResource(device, HeapProperty::Upload, desc.NumDescriptors * 1024);
		m_gpuVA  = m_upload->GetGPUVirtualAddress();
		D3D12_RANGE readRange = { 0, 0 };
		m_upload->Map(0, &readRange, (void**)&m_data);

		reset(m_gpuHandle);
	}

	void ScratchBufferD3D12::destroy()
	{