Synchronization in Tutorial 06 : Images

[overv]

Synchronization in Tutorial 06 : Images

[Overv]

With regards to your global barrier, it may be preferable to keep the old code to be explicit about the intend, but note that it is not actually necessary. Do you agree?

[qnope]

I disagree for this transition :
transitionImageLayout(textureImage, VK_FORMAT_R8G8B8A8_UNORM, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);

You want to transition the image from TRANSFER_DST to SHADER_READ.
As I wrote above, you must wait the transfer stage to be finished. And you want to use it at the Fragment Shader stage.
That's said, you must flush the caches used for transfers with VK_ACCESS_TRANSFER_WRITE and invalidate caches red by the FRAGMENT_SHADER using VK_ACCESS_SHADER_READ.

So, if you do not want use a "all blocking barrier", you should, IMHO, at least use :

srcStage = TRANSFER;
dstStage = FRAGMENT_SHADER
srcAccess = TRANSFER_WRITE;
dstAccess = SHADER_READ;

[qnope]

Actually, for the dstStage/Access, a TOP_OF_PIPE / 0 should be correct.

[Overv]

For your first proposal, am I understanding correctly that you want to change

if (oldLayout == VK_IMAGE_LAYOUT_PREINITIALIZED && newLayout == VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL) {
    barrier.srcAccessMask = VK_ACCESS_HOST_WRITE_BIT;
    barrier.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
} else if (oldLayout == VK_IMAGE_LAYOUT_PREINITIALIZED && newLayout == VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL) {
    barrier.srcAccessMask = VK_ACCESS_HOST_WRITE_BIT;
    barrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
}

To:

if (oldLayout == VK_IMAGE_LAYOUT_PREINITIALIZED && newLayout == VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL) {
    barrier.srcAccessMask = 0;
    barrier.dstAccessMask = VK_ACCESS_TRANSFER_READ_BIT;
} else if (oldLayout == VK_IMAGE_LAYOUT_PREINITIALIZED && newLayout == VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL) {
    barrier.srcAccessMask = 0;
    barrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
}

Because if I do this, I still get a warning from the validation layers despite your pull request.

[qnope]

It is correct, try to upgrade your validation layer, I pushed a fix that correct this bug :
KhronosGroup/Vulkan-LoaderAndValidationLayers#1142

[Overv]

I am aware, but I'm already using the latest version.

[qnope]

I do not have any problem
I am using archlinux and use vulkan-extra-layers 1.0.37

[qnope]

Here is the code I am using :

vk::ImageMemoryBarrier Transferer::transitionImage(Image image,
                                                   vk::ImageLayout oldLayout,
                                                   vk::ImageLayout newLayout,
                                                   vk::ImageSubresourceRange imageSubResourceRange) {
    vk::AccessFlags src, dst;

    if(oldLayout == vk::ImageLayout::eUndefined || oldLayout == vk::ImageLayout::ePreinitialized)
        src = vk::AccessFlags();

    // If it was in transferDst, we wait for transferWrite
    else if(oldLayout == vk::ImageLayout::eTransferDstOptimal)
        src = vk::AccessFlagBits::eTransferWrite;

    // If it was in transferSrc, we wait for transferRead
    else if(oldLayout == vk::ImageLayout::eTransferSrcOptimal)
        src = vk::AccessFlagBits::eTransferRead; // Useless since make available a read is meaningless

    else
        assert(!"This oldLayout is not managed");

    // If it will be transferSrcOptimal, it should be ready at transferRead
    if(newLayout == vk::ImageLayout::eTransferSrcOptimal)
        dst = vk::AccessFlagBits::eTransferRead;

    // If it will be transferDstOptimal
    else if(newLayout == vk::ImageLayout::eTransferDstOptimal)
        dst = vk::AccessFlagBits::eTransferWrite; // Myst be useless since invalidate for a write

    // If it will be shaderReadOnlyOptimal, it should be ready at shaderRead
    else if(newLayout == vk::ImageLayout::eShaderReadOnlyOptimal)
        dst = vk::AccessFlagBits::eShaderRead;

    else
        assert(!"This newLayout is not managed");

    return vk::ImageMemoryBarrier(src, dst, oldLayout, newLayout, VK_QUEUE_FAMILY_IGNORED, VK_QUEUE_FAMILY_IGNORED,
                                  image, imageSubResourceRange);
}

[Overv]

I'm also using version 1.0.37 of the validation layers, although I don't know what "vulkan-extra-layers" is.

[qnope]

I guess it is for other validation layers, but 1.0.37 should be good.
What is the message that is gave by the validation layers?

[Overv]

Source AccessMask 0 [None] must have required access bit 16384 [VK_ACCESS_HOST_WRITE_BIT] when layout is VK_IMAGE_LAYOUT_PREINITIALIZED, unless the app has previously added a barrier for this transition.

[qnope]

It is weird ^^, I do not have any problem... Try to compile by yourself the validation layers? Else, try to compile my VulkanExample Scene and launch it to see if in your case you have the same error or not.

[Overv]

Ah, I had a configuration error that caused it to use DLLs from an older SDK. It runs without errors now, I'll update the tutorial.