1// Copyright (c) 2020,2023 Qualcomm Technologies, Inc. 2// 3// SPDX-License-Identifier: CC-BY-4.0 4 5include::{generated}/meta/{refprefix}VK_QCOM_rotated_copy_commands.adoc[] 6 7=== Other Extension Metadata 8 9*Last Modified Date*:: 10 2023-12-13 11*Interactions and External Dependencies*:: 12 - This extension interacts with `apiext:VK_KHR_swapchain` 13 - This extension interacts with `apiext:VK_KHR_surface` 14*Contributors*:: 15 - Jeff Leger, Qualcomm Technologies, Inc. 16 - Matthew Netsch, Qualcomm Technologies, Inc. 17 18=== Description 19 20This extension extends adds an optional rotation transform to copy commands 21flink:vkCmdBlitImage2KHR, flink:vkCmdCopyImageToBuffer2KHR and 22flink:vkCmdCopyBufferToImage2KHR. 23When copying between two resources, where one resource contains rotated 24content and the other does not, a rotated copy may be desired. 25This extension may be used in combination with VK_QCOM_render_pass_transform 26which adds rotated render passes. 27 28This extension adds an extension structure to the following commands: 29vkCmdBlitImage2KHR, vkCmdCopyImageToBuffer2KHR and 30vkCmdCopyBufferToImage2KHR 31 32 33=== Issues 34 351) What is an appropriate name for the added extension structure? The style 36guide says "`Structures which extend other structures through the 37pname:pNext chain should reflect the name of the base structure they 38extend.`", but in this case a single extension structure is used to extend 39three base structures (vkCmdBlitImage2KHR, vkCmdCopyImageToBuffer2KHR and 40vkCmdCopyBufferToImage2KHR). 41Creating three identical structures with unique names seemed undesirable. 42 43*RESOLVED*: Deviate from the style guide for extension structure naming. 44 45 462) Should this extension add a rotation capability to vkCmdCopyImage2KHR? 47 48*RESOLVED*: No. 49Use of rotated vkCmdBlitImage2KHR can fully address this use case. 50 513) Should this extension add a rotation capability to vkCmdResolveImage2KHR? 52 53*RESOLVED* No. 54Use of vkCmdResolveImage2KHR is very slow and extremely bandwidth intensive 55on Qualcomm's GPU architecture and use of pResolveAttachments in 56vkRenderPass is the strongly preferred approach. 57Therefore, we choose not to introduce a rotation capability to 58vkCmdResolveImage2KHR. 59 60include::{generated}/interfaces/VK_QCOM_rotated_copy_commands.adoc[] 61 62=== Version History 63 64 * Revision 1, 2020-09-19 (Jeff Leger) 65 * Revision 2, 2023-12-13 (Matthew Netsch) 66 ** Relax dependency on VK_KHR_swapchain 67