Backends: Vulkan: handle viewport surface creation failure without crashing. (#9068)

backends/imgui_impl_vulkan.cpp

@@ -29,6 +29,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2025-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2025-11-13: [Docking] Handle viewport surface creation failure without crashing. (#9068)
 //  2025-10-15: Vulkan: Added IMGUI_IMPL_VULKAN_VOLK_FILENAME to configure path to volk.h header. (#9008)
 //  2025-09-26: *BREAKING CHANGE*: moved some fields in ImGui_ImplVulkan_InitInfo: init_info.RenderPass --> init_info.PipelineInfoMain.RenderPass, init_info.Subpass --> init_info.PipelineInfoMain.Subpass, init_info.MSAASamples --> init_info.PipelineInfoMain.MSAASamples, init_info.PipelineRenderingCreateInfo --> init_info.PipelineInfoMain.PipelineRenderingCreateInfo.
 //  2025-09-26: *BREAKING CHANGE*: renamed ImGui_ImplVulkan_MainPipelineCreateInfo to ImGui_ImplVulkan_PipelineInfo. Introduced very recently so shouldn't affect many users.
@@ -1957,7 +1958,6 @@ static void ImGui_ImplVulkan_CreateWindow(ImGuiViewport* viewport)
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
     ImGui_ImplVulkan_ViewportData* vd = IM_NEW(ImGui_ImplVulkan_ViewportData)();
-    viewport->RendererUserData = vd;
     ImGui_ImplVulkanH_Window* wd = &vd->Window;
     ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
 
@@ -1966,14 +1966,23 @@ static void ImGui_ImplVulkan_CreateWindow(ImGuiViewport* viewport)
     VkResult err = (VkResult)platform_io.Platform_CreateVkSurface(viewport, (ImU64)v->Instance, (const void*)v->Allocator, (ImU64*)&wd->Surface);
     check_vk_result(err);
     
+    // Check if surface creation failed
+    if (err != VK_SUCCESS || wd->Surface == VK_NULL_HANDLE)
+    {
+        IM_DELETE(vd);
+        return;
+    }
+
     // Check for WSI support
     VkBool32 res;
     vkGetPhysicalDeviceSurfaceSupportKHR(v->PhysicalDevice, v->QueueFamily, wd->Surface, &res);
     if (res != VK_TRUE)
     {
-        IM_ASSERT(0); // Error: no WSI support on physical device
+        vkDestroySurfaceKHR(v->Instance, wd->Surface, v->Allocator); // Error: no WSI support on physical device, clean up and return
+        IM_DELETE(vd);
         return;
     }
+    viewport->RendererUserData = nullptr;
 
     // Select Surface Format
     ImGui_ImplVulkan_PipelineInfo* pipeline_info = &v->PipelineInfoForViewports;
@@ -2050,6 +2059,8 @@ static void ImGui_ImplVulkan_RenderWindow(ImGuiViewport* viewport, void*)
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
     ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData;
+    if (vd == nullptr)
+        return;
     ImGui_ImplVulkanH_Window* wd = &vd->Window;
     ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
     VkResult err;
@@ -2197,6 +2208,8 @@ static void ImGui_ImplVulkan_SwapBuffers(ImGuiViewport* viewport, void*)
 {
     ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData();
     ImGui_ImplVulkan_ViewportData* vd = (ImGui_ImplVulkan_ViewportData*)viewport->RendererUserData;
+    if (vd == nullptr)
+        return;
     ImGui_ImplVulkanH_Window* wd = &vd->Window;
     ImGui_ImplVulkan_InitInfo* v = &bd->VulkanInitInfo;
 

docs/CHANGELOG.txt

@@ -158,6 +158,7 @@ Docking+Viewports Branch:
 - Backends:
   - DirectX12: Fixed an issue in synchronization logic improving rendering
     throughput for secondary viewports. (#9025, #8961)
+  - Vulkan: handle viewport surface creation failure without crashing. (#9068) [@zentia]
 
 
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