Backends: Vulkan: fixed validation errors during window detach in multi-viewport mode. (#8600, #8176)

backends/imgui_impl_vulkan.cpp

@@ -26,6 +26,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-05-07- Vulkan: Fixed validation errors during window detach in multi-viewport mode. (#8600, #8176)
 //  2025-05-07: Vulkan: Load dynamic rendering functions using vkGetDeviceProcAddr() + try both non-KHR and KHR versions. (#8600, #8326, #8365)
 //  2025-04-07: Vulkan: Deep-copy ImGui_ImplVulkan_InitInfo::PipelineRenderingCreateInfo's pColorAttachmentFormats buffer when set, in order to reduce common user-error of specifying a pointer to data that gets out of scope. (#8282)
 //  2025-02-14: *BREAKING CHANGE*: Added uint32_t api_version to ImGui_ImplVulkan_LoadFunctions().
@@ -1086,6 +1087,8 @@ void    ImGui_ImplVulkan_DestroyDeviceObjects()
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
 static void ImGui_ImplVulkan_LoadDynamicRenderingFunctions(uint32_t api_version, PFN_vkVoidFunction(*loader_func)(const char* function_name, void* user_data), void* user_data)
 {
+    IM_UNUSED(api_version);
+
     // Manually load those two (see #5446, #8326, #8365, #8600)
     // - Try loading core (non-KHR) versions first (this will work for Vulkan 1.3+ and the device supports dynamic rendering)
     ImGuiImplVulkanFuncs_vkCmdBeginRenderingKHR = reinterpret_cast<PFN_vkCmdBeginRenderingKHR>(loader_func("vkCmdBeginRendering", user_data));
@@ -1667,6 +1670,82 @@ void ImGui_ImplVulkanH_CreateOrResizeWindow(VkInstance instance, VkPhysicalDevic
     (void)instance;
     ImGui_ImplVulkanH_CreateWindowSwapChain(physical_device, device, wd, allocator, width, height, min_image_count);
     ImGui_ImplVulkanH_CreateWindowCommandBuffers(physical_device, device, wd, queue_family, allocator);
+
+    // FIXME: to submit the command buffer, we need a queue. In the examples folder, the ImGui_ImplVulkanH_CreateOrResizeWindow function is called
+    // before the ImGui_ImplVulkan_Init function, so we don't have access to the queue yet. Here we have the queue_family that we can use to grab
+    // a queue from the device and submit the command buffer. It would be better to have access to the queue as suggested in the FIXME below.
+    VkCommandPool command_pool;
+    VkCommandPoolCreateInfo pool_info = {};
+    pool_info.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
+    pool_info.queueFamilyIndex = queue_family;
+    pool_info.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT;
+    VkResult err = vkCreateCommandPool(device, &pool_info, allocator, &command_pool);
+    check_vk_result(err);
+
+    VkFenceCreateInfo fence_info = {};
+    fence_info.sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
+    VkFence fence;
+    err = vkCreateFence(device, &fence_info, allocator, &fence);
+    check_vk_result(err);
+
+    VkCommandBufferAllocateInfo alloc_info = {};
+    alloc_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
+    alloc_info.commandPool = command_pool;
+    alloc_info.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
+    alloc_info.commandBufferCount = 1;
+    VkCommandBuffer command_buffer;
+    err = vkAllocateCommandBuffers(device, &alloc_info, &command_buffer);
+    check_vk_result(err);
+
+    VkCommandBufferBeginInfo begin_info = {};
+    begin_info.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
+    begin_info.flags = VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT;
+    err = vkBeginCommandBuffer(command_buffer, &begin_info);
+    check_vk_result(err);
+
+    // Transition the images to the correct layout for rendering
+    for (uint32_t i = 0; i < wd->ImageCount; i++)
+    {
+        VkImageMemoryBarrier barrier = {};
+        barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
+        barrier.image = wd->Frames[i].Backbuffer;
+        barrier.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
+        barrier.newLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
+        barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+        barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
+        barrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
+        barrier.subresourceRange.levelCount = 1;
+        barrier.subresourceRange.layerCount = 1;
+        vkCmdPipelineBarrier(command_buffer, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, 0, 0, nullptr, 0, nullptr, 1, &barrier);
+    }
+
+    err = vkEndCommandBuffer(command_buffer);
+    check_vk_result(err);
+    VkSubmitInfo submit_info = {};
+    submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+    submit_info.commandBufferCount = 1;
+    submit_info.pCommandBuffers = &command_buffer;
+
+    VkQueue queue;
+    vkGetDeviceQueue(device, queue_family, 0, &queue);
+    err = vkQueueSubmit(queue, 1, &submit_info, fence);
+    check_vk_result(err);
+    err = vkWaitForFences(device, 1, &fence, VK_TRUE, UINT64_MAX);
+    check_vk_result(err);
+    err = vkResetFences(device, 1, &fence);
+    check_vk_result(err);
+
+    err = vkResetCommandPool(device, command_pool, 0);
+    check_vk_result(err);
+
+    // Destroy command buffer and fence and command pool
+    vkFreeCommandBuffers(device, command_pool, 1, &command_buffer);
+    vkDestroyCommandPool(device, command_pool, allocator);
+    vkDestroyFence(device, fence, allocator);
+    command_pool = VK_NULL_HANDLE;
+    command_buffer = VK_NULL_HANDLE;
+    fence = VK_NULL_HANDLE;
+    queue = VK_NULL_HANDLE;
 }
 
 void ImGui_ImplVulkanH_DestroyWindow(VkInstance instance, VkDevice device, ImGui_ImplVulkanH_Window* wd, const VkAllocationCallbacks* allocator)

docs/CHANGELOG.txt

@@ -121,6 +121,9 @@ Other changes:
   specifying a pointer to data that gets out of scope. (#8282)
 - Backends: Vulkan: Load dynamic rendering functions using vkGetDeviceProcAddr()
   + try both non-KHR and KHR versions. (#8600, #8326, #8365) [@ChrisTom-94]
+- Backends: Vulkan: fixed validation errors in window create/resize helpers used by examples
+  and by multi-viewports implementation, which would typically trigger errors while detaching
+  secondary viewports. (#8600, #8176) [@ChrisTom-94]
 - Examples: DirectX12+Win32: also test for IsIconic() for sleeping since we don't seem to
   get a DXGI_STATUS_OCCLUDED signal when minimized. (#8603) [@dooann]