c++ - 我可以在命令缓冲区中多次记录 vkCmdPipelineBarrier 吗？

Question

我有一个来自 vkSwapchain 的 vkImage。我的目标很简单，就是在这个图像中渲染一个三角形。所以我创建了一个命令缓冲区并记录为以下命令。

1. vkBeginCommandBuffer
2. vkCmdPipelineBarrier(从LAYOUT_UNDEFINED到COLOR_ATTACHMENT_OPTIMAL)
3. vkCmdBeginRenderPass
4. 画出我的三角形。
5. vkCmdEndRenderPass
6. vkCmdPipelineBarrier(从COLOR_ATTACHMENT_OPTIMAL到PRESENT_SRC)
7. vkEndCommandBuffer

最后，我调用了 vkQueueSubmit 以在屏幕上显示一个三角形。但是当 second vkCmdPipelineBarrier 执行时，验证层说:

VUID-VkImageMemoryBarrier-oldLayout-01197: For image 0x4 you cannot transition the layout of aspect=1 level=0 layer=0 from VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL when the previous known layout is VK_IMAGE_LAYOUT_PRESENT_SRC_KHR.

和

UNASSIGNED-CoreValidation-DrawState-InvalidImageLayout: Submitted command buffer expects image 0x4 (subresource: aspectMask 0x1 array layer 0, mip level 0) to be in layout VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL--instead, current layout is VK_IMAGE_LAYOUT_PRESENT_SRC_KHR.

但我确定图像布局将在那时 COLOR_ATTACHMENT_OPTIMAL。我不知道为什么验证层向我提示。

我搜索了 API 文档，但找不到任何 vkCmdPipelineBarrier 的限制。他们说这个命令执行队列所有权转移(如果需要)和布局转换。

下面是我的代码。

//////////////////////////////////////////////////////
// First layout transition
//////////////////////////////////////////////////////
VkImageMemoryBarrier vkGraphicsImageMemoryBarrier
{
    VkStructureType::VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
    nullptr,
    0,
    VkAccessFlagBits::VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
    VkImageLayout::VK_IMAGE_LAYOUT_UNDEFINED,
    VkImageLayout::VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
    VK_QUEUE_FAMILY_IGNORED,
    VK_QUEUE_FAMILY_IGNORED,
    this->sSwapchain.vulkanImageList()[nImageIndex],
    VkImageSubresourceRange
    {
        VkImageAspectFlagBits::VK_IMAGE_ASPECT_COLOR_BIT,
        0,
        VK_REMAINING_MIP_LEVELS,
        0,
        VK_REMAINING_ARRAY_LAYERS
    }
};

vkCmdPipelineBarrier(
    this->sGraphicsCommandBufferList[nImageIndex],
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
    0,
    0, nullptr,
    0, nullptr,
    1, &vkGraphicsImageMemoryBarrier);

//
//  Draws a triangle.
//

//////////////////////////////////////////////////////
// Second layout transition and ownership transfer
//////////////////////////////////////////////////////
VkImageMemoryBarrier vkGraphicsImageMemoryBarrier
{
    VkStructureType::VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
    nullptr,
    VkAccessFlagBits::VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
    0,
    VkImageLayout::VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
    VkImageLayout::VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
    this->nGraphicsFamily,
    this->nPresentFamily,
    this->sSwapchain.vulkanImageList()[nImageIndex],
    VkImageSubresourceRange
    {
        VkImageAspectFlagBits::VK_IMAGE_ASPECT_COLOR_BIT,
        0,
        VK_REMAINING_MIP_LEVELS,
        0,
        VK_REMAINING_ARRAY_LAYERS
    }
};
VkImageMemoryBarrier vkPresentImageMemoryBarrier
{
    VkStructureType::VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
    nullptr,
    0,
    0,
    VkImageLayout::VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL,
    VkImageLayout::VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
    this->nGraphicsFamily,
    this->nPresentFamily,
    this->sSwapchain.vulkanImageList()[nImageIndex],
    VkImageSubresourceRange
    {
        VkImageAspectFlagBits::VK_IMAGE_ASPECT_COLOR_BIT,
        0,
        VK_REMAINING_MIP_LEVELS,
        0,
        VK_REMAINING_ARRAY_LAYERS
    }
};

//
//  Below call produces the above validation message.
//
vkCmdPipelineBarrier(
    this->sGraphicsCommandBufferList[nImageIndex],
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
    0,
    0, nullptr,
    0, nullptr,
    1, &vkGraphicsImageMemoryBarrier);
vkCmdPipelineBarrier(
    this->sPresentCommandBufferList[nImageIndex],
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT,
    VkPipelineStageFlagBits::VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT,
    0,
    0, nullptr,
    0, nullptr,
    1, &vkPresentImageMemoryBarrier);

尽管有验证错误消息，我还是得到了一个三角形。这是验证层错误吗？

如有任何帮助，我们将不胜感激。

Answer 1

您可以在命令缓冲区中记录多少个管道屏障没有限制(内存限制除外)

然而，不需要那个特定的屏障，因为相同的屏障可以由 renderpass 隐式完成。验证提示图像布局已经存在这一事实意味着您已经以这种方式进行了设置。创建 renderpass 时检查附件的最终布局。