1// Copyright 2016-2024 The Khronos Group Inc.
2//
3// SPDX-License-Identifier: CC-BY-4.0
4
5include::{generated}/meta/{refprefix}VK_KHR_maintenance1.adoc[]
6
7=== Other Extension Metadata
8
9*Last Modified Date*::
10    2018-03-13
11*Contributors*::
12  - Dan Ginsburg, Valve
13  - Daniel Koch, NVIDIA
14  - Daniel Rakos, AMD
15  - Jan-Harald Fredriksen, ARM
16  - Faith Ekstrand, Intel
17  - Jeff Bolz, NVIDIA
18  - Jesse Hall, Google
19  - John Kessenich, Google
20  - Michael Worcester, Imagination Technologies
21  - Neil Henning, Codeplay Software Ltd.
22  - Piers Daniell, NVIDIA
23  - Slawomir Grajewski, Intel
24  - Tobias Hector, Imagination Technologies
25  - Tom Olson, ARM
26
27=== Description
28
29`VK_KHR_maintenance1` adds a collection of minor features that were
30intentionally left out or overlooked from the original Vulkan 1.0 release.
31
32The new features are as follows:
33
34  * Allow 2D and 2D array image views to be created from 3D images, which
35    can then be used as color framebuffer attachments.
36    This allows applications to render to slices of a 3D image.
37  * Support flink:vkCmdCopyImage between 2D array layers and 3D slices.
38    This extension allows copying from layers of a 2D array image to slices
39    of a 3D image and vice versa.
40  * Allow negative height to be specified in the
41    slink:VkViewport::pname:height field to perform y-inversion of the
42    clip-space to framebuffer-space transform.
43    This allows apps to avoid having to use `gl_Position.y = -gl_Position.y`
44    in shaders also targeting other APIs.
45  * Allow implementations to express support for doing just transfers and
46    clears of image formats that they otherwise support no other format
47    features for.
48    This is done by adding new format feature flags
49    ename:VK_FORMAT_FEATURE_TRANSFER_SRC_BIT_KHR and
50    ename:VK_FORMAT_FEATURE_TRANSFER_DST_BIT_KHR.
51  * Support flink:vkCmdFillBuffer on transfer-only queues.
52    Previously flink:vkCmdFillBuffer was defined to only work on command
53    buffers allocated from command pools which support graphics or compute
54    queues.
55    It is now allowed on queues that just support transfer operations.
56  * Fix the inconsistency of how error conditions are returned between the
57    flink:vkCreateGraphicsPipelines and flink:vkCreateComputePipelines
58    functions and the flink:vkAllocateDescriptorSets and
59    flink:vkAllocateCommandBuffers functions.
60  * Add new ename:VK_ERROR_OUT_OF_POOL_MEMORY_KHR error so implementations
61    can give a more precise reason for flink:vkAllocateDescriptorSets
62    failures.
63  * Add a new command flink:vkTrimCommandPoolKHR which gives the
64    implementation an opportunity to release any unused command pool memory
65    back to the system.
66
67=== Promotion to Vulkan 1.1
68
69All functionality in this extension is included in core Vulkan 1.1, with the
70KHR suffix omitted.
71The original type, enum and command names are still available as aliases of
72the core functionality.
73
74include::{generated}/interfaces/VK_KHR_maintenance1.adoc[]
75
76=== Issues
77
78  . Are viewports with zero height allowed?
79+
80*RESOLVED*: Yes, although they have low utility.
81
82=== Version History
83
84  * Revision 1, 2016-10-26 (Piers Daniell)
85  ** Internal revisions
86  * Revision 2, 2018-03-13 (Jon Leech)
87  ** Add issue for zero-height viewports
88