commit 9f8b71691386b3300f7de68034637b5cbbe4f84b
author Alex Smith <asmith@feralinteractive.com> Tue Jan 10 09:51:22 2017 +0000
committer Tobin Ehlis <tobine@google.com> Tue Jan 10 13:41:51 2017 -0700
tree 8b58554c441705880590596f7465f451cbdf61ea
parent 82a2c181e32f4bc47e922a4bf0ff9b47526a25e4

layers: Transition each aspect individually in TransitionImageLayouts

This fixes the possibility of spurious validation errors like the following,
when attempting to transition multiple aspects of an image after only a subset
of those aspects have previously been used in the command buffer:

  "Cannot query for VkImage 0x599 layout when combined aspect mask 6 has
   multiple initial layout types: VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL and
   VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL"

The specific case where this bug was encountered was where both the depth and
stencil aspects of an image were initially in the TRANSFER_DST_OPTIMAL layout.
The first command in the command buffer to reference the image was a
vkCmdClearDepthStencilImage on only the depth aspect of the image, followed
later by a vkCmdPipelineBarrier to transition both aspects to the
DEPTH_STENCIL_ATTACHMENT_OPTIMAL layout.

Since TransitionImageLayouts tries to look up the initial state for all
aspects at the same time, it was picking up the state based on the depth
aspect because of the previous use of that (which had both initialLayout
and layout set to TRANSFER_DST_OPTIMAL), and then calling SetLayout for all
aspects with only the new layout. Since the stencil aspect didn't have any
currently recorded state, it was being added with both initialLayout and
layout set to the new layout, causing a mismatch between the initialLayout for
the two aspects and therefore the spurious error above.

Fix by updating the state for each aspect individually.