vulkan-wsi-layer/wsi/extensions/frame_boundary.cpp

/*
 * Copyright (c) 2024-2025 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
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 * furnished to do so, subject to the following conditions:
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 * The above copyright notice and this permission notice shall be included in all
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 *
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 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * SOFTWARE.
 */

/**
 * @file frame_boundary.cpp
 *
 * @brief Contains the implementation for the VK_EXT_frame_boundary extension.
 */
#include "frame_boundary.hpp"

namespace wsi
{

wsi_ext_frame_boundary::wsi_ext_frame_boundary(const layer::device_private_data &device_data)
   : m_handle_frame_boundary_events(device_data.should_layer_handle_frame_boundary_events())
{
}

std::optional<VkFrameBoundaryEXT> wsi_ext_frame_boundary::handle_frame_boundary_event(
   const VkPresentInfoKHR *present_info, VkImage *current_image_to_be_presented)
{
   /* If frame boundary feature is not enabled by the application, the layer will
    * pass its own frame boundary events back to ICD. Otherwise, let the application
    * handle the frame boundary events. */

   /* First, check if the application passed any frame boundary events and if that's
    * the case, just forward it at queue submission. */
   auto application_frame_boundary_event = wsi::create_frame_boundary(*present_info);
   if (application_frame_boundary_event.has_value())
   {
      return application_frame_boundary_event;
   }

   if (m_handle_frame_boundary_events)
   {
      return create_frame_boundary(current_image_to_be_presented);
   }

   return std::nullopt;
}

std::optional<VkFrameBoundaryEXT> create_frame_boundary(const VkPresentInfoKHR &present_info)
{
   auto *present_frame_boundary =
      util::find_extension<VkFrameBoundaryEXT>(VK_STRUCTURE_TYPE_PRESENT_ID_KHR, present_info.pNext);

   /* Extract the VkFrameBoundaryEXT structure to avoid passing other, unrelated structures to vkQueueSubmit */
   if (present_frame_boundary != nullptr)
   {
      return util::shallow_copy_extension(present_frame_boundary);
   }

   return std::nullopt;
}

bool wsi_ext_frame_boundary::should_layer_handle_frame_boundary_events() const
{
   return m_handle_frame_boundary_events;
}

VkFrameBoundaryEXT wsi_ext_frame_boundary::create_frame_boundary(VkImage *image)
{
   VkFrameBoundaryEXT frame_boundary{};
   frame_boundary.pNext = nullptr;
   frame_boundary.sType = VK_STRUCTURE_TYPE_FRAME_BOUNDARY_EXT;
   frame_boundary.flags = VK_FRAME_BOUNDARY_FRAME_END_BIT_EXT;
   /* Number of presented images by swapchain as the frame boundary
    * would not work as when the page flip thread is running, the
    * number frame ID could remain the same until the image is picked
    * up by the thread so we use our own counter for the frame boundary. */
   frame_boundary.frameID = m_current_frame_boundary_id++;
   frame_boundary.imageCount = 1;
   frame_boundary.pImages = image;
   frame_boundary.pBuffers = nullptr;
   frame_boundary.bufferCount = 0;

   /* Create an unique identifier for the layer in case tools make use of it.
    * The number below is derived from converting characters 'WSI' into
    * their numerical representation from the ASCII table. */
   frame_boundary.tagName = 0x575349;

   /* No additional data attached */
   frame_boundary.tagSize = 0;
   frame_boundary.pTag = nullptr;

   return frame_boundary;
}

std::optional<VkFrameBoundaryEXT> handle_frame_boundary_event(const VkPresentInfoKHR *present_info,
                                                              VkImage *current_image_to_be_presented,
                                                              wsi::wsi_ext_frame_boundary *frame_boundary)
{
   if (frame_boundary)
   {
      return frame_boundary->handle_frame_boundary_event(present_info, current_image_to_be_presented);
   }

   return create_frame_boundary(*present_info);
}

}