message: Handle a NULL vertex buffer in vulkan state
  * It's perfectly valid to have a vertex buffer in slots 0 and 4 with nothing in
  between, so we should be sure to skip any invalid vertex buffer bindings.
diff: @@ -114,11 +114,16 @@ void VulkanRenderState::BeginRenderPassAndApplyState(VkCommandBuffer cmd, Pipeli
  ibuffer.offs, ibuffer.bytewidth == 4 ? VK_INDEX_TYPE_UINT32 : VK_INDEX_TYPE_UINT16);
  for(size_t i = 0; i < vbuffers.size(); i++)
  + {
  + if(vbuffers[i].buf == ResourceId())
  + continue;
  +
  ObjDisp(cmd)->CmdBindVertexBuffers(
  Unwrap(cmd), (uint32_t)i, 1,
  UnwrapPtr(GetResourceManager()->GetCurrentHandle<VkBuffer>(vbuffers[i].buf)),
  &vbuffers[i].offs);
  }
  +}
  void VulkanRenderState::BindPipeline(VkCommandBuffer cmd, PipelineBinding binding, bool subpass0)
  {
  