ImGui scales instead of resizing on Wayland with GLFW and VULKAN about imgui

[AndreiNego]

Added two callbacks in the main function to solve the issue, although just one should be enough.

glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+Vulkan example", nullptr, nullptr);
if (!glfwVulkanSupported())
{
printf("GLFW: Vulkan Not Supported\n");
return 1;
}

glfwSetWindowSizeCallback(window, [](GLFWwindow* window, int width, int height){g_SwapChainRebuild = true;});
glfwSetFramebufferSizeCallback(window, [](GLFWwindow* window, int width, int height){g_SwapChainRebuild = true;});

[AndreiNego]

More info on the issue:
"(VK_SUBOPTIMAL_KHR happens only on X11/XCB or/and xWayland)
In Wayland resize logic completely different from other WM, and way too many platforms to support if you rly care about crossplatform. (and Wayland has too many features that I left untested, I have no idea how application will react to those WM features(exampel I was talking about “zoom” part of screen, what application do in this case how it rendered… no idea))"
https://community.khronos.org/t/vk-suboptimal-khr-is-it-safe-to-use-it-as-window-resize-detection/107848/5

[ocornut]

I am wondering if we could simply fix it by changing:

        // Resize swap chain?
        if (g_SwapChainRebuild)
        {
            int width, height;
            glfwGetFramebufferSize(window, &width, &height);
            if (width > 0 && height > 0)
            {
                ImGui_ImplVulkan_SetMinImageCount(g_MinImageCount);
                ImGui_ImplVulkanH_CreateOrResizeWindow(g_Instance, g_PhysicalDevice, g_Device, &g_MainWindowData, g_QueueFamily, g_Allocator, width, height, g_MinImageCount);
                g_MainWindowData.FrameIndex = 0;
                g_SwapChainRebuild = false;
            }
        }

to

        // Resize swap chain?
        int fb_width, fb_height;
        glfwGetFramebufferSize(window, &fb_width, &fb_height);
        if (g_SwapChainRebuild || g_MainWindowData.Width != fb_width || g_MainWindowData.Height != fb_height)
            if (fb_width > 0 && fb_height > 0)
            {
                ImGui_ImplVulkan_SetMinImageCount(g_MinImageCount);
                ImGui_ImplVulkanH_CreateOrResizeWindow(g_Instance, g_PhysicalDevice, g_Device, &g_MainWindowData, g_QueueFamily, g_Allocator, fb_width, fb_height, g_MinImageCount);
                g_MainWindowData.FrameIndex = 0;
                g_SwapChainRebuild = false;
            }

Could you test it?

Can you already see if things works correctly on your system with the SDL+Vulkan example?

Thank you!

[AndreiNego]

Hi,
I've tested it and it worked perfectly.
Unfortunately, for SDL I am unable to get SDL.h to install on my system. I have two potential packages that provide the header but none of them actually install it.

[ocornut]

Pushed fixes as a47bfb1 and 7538ca6
Looking at equivalent SDL example it seemed clear the same thing would happen.
If you get around to install SDL please verify it before and after 🙏

[AndreiNego]

For SDL the problem does not exist.
SDL does not open a Wayland native window but an X window.
The flag is raised for VK_ERROR_OUT_OF_DATE_KHR during resize