c++ - 下次转让时，我是否需要将所有权*返还*到转让队列中？

我计划使用一个vulkan同步示例作为如何处理不经常更新的统一缓冲区的参考。具体来说，我在看这个：

vkBeginCommandBuffer(...);

// Submission guarantees the host write being complete, as per
// https://www.khronos.org/registry/vulkan/specs/1.0/html/vkspec.html#synchronization-submission-host-writes
// So no need for a barrier before the transfer

// Copy the staging buffer contents to the vertex buffer
VkBufferCopy vertexCopyRegion = {
    .srcOffset = stagingMemoryOffset,
    .dstOffset = vertexMemoryOffset,
    .size      = vertexDataSize};

vkCmdCopyBuffer(
    commandBuffer,
    stagingBuffer,
    vertexBuffer,
    1,
    &vertexCopyRegion);


// If the graphics queue and transfer queue are the same queue
if (isUnifiedGraphicsAndTransferQueue)
{
    // If there is a semaphore signal + wait between this being submitted and
    // the vertex buffer being used, then skip this pipeline barrier.

    // Pipeline barrier before using the vertex data
    // Note that this can apply to all buffers uploaded in the same way, so
    // ideally batch all copies before this.
    VkMemoryBarrier memoryBarrier = {
        ...
        .srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT,                           
        .dstAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT};

    vkCmdPipelineBarrier(
        ...
        VK_PIPELINE_STAGE_TRANSFER_BIT ,      // srcStageMask
        VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,   // dstStageMask
        1,                                    // memoryBarrierCount
        &memoryBarrier,                       // pMemoryBarriers
        ...);


    vkEndCommandBuffer(...);

    vkQueueSubmit(unifiedQueue, ...);
}
else
{
    // Pipeline barrier to start a queue ownership transfer after the copy
    VkBufferMemoryBarrier bufferMemoryBarrier = {
        ...
        .srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT,                           
        .dstAccessMask = 0,
        .srcQueueFamilyIndex = transferQueueFamilyIndex,
        .dstQueueFamilyIndex = graphicsQueueFamilyIndex,
        .buffer = vertexBuffer,
        ...};

    vkCmdPipelineBarrier(
        ...
        VK_PIPELINE_STAGE_TRANSFER_BIT ,      // srcStageMask
        VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT, // dstStageMask
        1,                                    // bufferMemoryBarrierCount
        &bufferMemoryBarrier,                 // pBufferMemoryBarriers
        ...);


    vkEndCommandBuffer(...);

    // Ensure a semaphore is signalled here which will be waited on by the graphics queue.
    vkQueueSubmit(transferQueue, ...);

    // Record a command buffer for the graphics queue.
    vkBeginCommandBuffer(...);

    // Pipeline barrier before using the vertex buffer, after finalising the ownership transfer
    VkBufferMemoryBarrier bufferMemoryBarrier = {
        ...
        .srcAccessMask = 0,                           
        .dstAccessMask = VK_ACCESS_VERTEX_ATTRIBUTE_READ_BIT,
        .srcQueueFamilyIndex = transferQueueFamilyIndex,
        .dstQueueFamilyIndex = graphicsQueueFamilyIndex,
        .buffer = vertexBuffer,
        ...};

    vkCmdPipelineBarrier(
        ...
        VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,    // srcStageMask
        VK_PIPELINE_STAGE_VERTEX_INPUT_BIT,   // dstStageMask
        ...
        1,                                    // bufferMemoryBarrierCount
        &bufferMemoryBarrier,                 // pBufferMemoryBarriers
        ...);


    vkEndCommandBuffer(...);

    vkQueueSubmit(graphicsQueue, ...);
}

在此示例中，我将其简化为：

map updated buffer which is host coherent
perform transfer in transfer queue to device local memory
    make sure to put a buffer memory barrier to handle the queue ownership transfer
perform normal draw commands
    make sure to put a buffer memory barrier to handle receiving of buffer in queue ownership

然后，我是否必须放弃传输队列再次复制该数据的功能？这些示例似乎都没有提到它，但是我可能会错过它。我真的看不到如何为相同的绘制命令缓冲区添加另一个缓冲区屏障，因为即使我没有什么要转移的东西，它也会在下一次提交时停顿，所以我只需要提交另一个命令缓冲区即可在我提交下一个转移操作之前将所有权转移排队？

即

//begin with transfer ownership
submit(copy)
submit(ownership to graphics)
submit(draw)
submit(ownership to transfer)
submit(copy)
submit(ownership to graphics)
submit(draw)
submit(draw)
submit(draw)
submit(ownership to transfer)
submit(copy)
submit(ownership to graphics)
submit(draw)

如果是这种情况，我不确定如何处理绘制和传输以及复制和绘制之间的信号量信号。刚开始时很容易，但是由于多个nflight框架而变得奇怪，因为绘制提交之间没有依赖关系。基本上，我想我需要设置我提交的最新绘图命令中的任何一个，以使用信号量来表示所有权的转移，这将表示副本，这将表示图形的所有权，以及是否在单独的线程上然后，我将检查此副本是否已提交，并且需要等待图形传输的所有权并重置提交的副本支票。但是我不确定下一帧没有这种依赖性，会发生什么，并且可以先于时间顺序在上一帧之前完成吗？