glfw: Window hints get reverted to default after window creation and cannot be set #201

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opened 2022-03-31 17:48:54 +00:00 by prime31 · 4 comments

prime31 commented

2022-03-31 17:48:54 +00:00

(Migrated from github.com)

Methods, e.g. my_window.hint(...) instead of glfwWindowHint(my_window, ...)

Possible fixes:

make window.hint public
dont keep resetting default hints after windows are created
expose as public c so that we can override and call raw GLFW methods ourselves when necessary

Once a window is created the GLFW wrapper resets all the hints to default. There is no public API available to set a hint so now we are stuck in a state where we can't work with hints at all. The README states that `hint` is a public method but it is not. > Methods, e.g. `my_window.hint(...)` instead of `glfwWindowHint(my_window, ...)` Possible fixes: - make `window.hint` public - dont keep resetting default hints after windows are created - expose as public `c` so that we can override and call raw GLFW methods ourselves when necessary

emidoots commented

2022-03-31 19:55:52 +00:00

(Migrated from github.com)

You're correct the README is out of date. The idea is that you pass a struct to createWindow with the hints, it sets them for you, and resets to defaults after the fact.

Is this approach problematic for interior with other C code, or are you having trouble finding the struct where window hints get passed in?

You're correct the README is out of date. The idea is that you pass a struct to createWindow with the hints, it sets them for you, and resets to defaults after the fact. Is this approach problematic for interior with other C code, or are you having trouble finding the struct where window hints get passed in?

prime31 commented

2022-03-31 22:29:19 +00:00

(Migrated from github.com)

    if (window->context.client != GLFW_NO_API)
    {
        _glfwInputError(GLFW_INVALID_VALUE,
                        "Vulkan: Window surface creation requires the window to have the client API set to GLFW_NO_API");
        return VK_ERROR_NATIVE_WINDOW_IN_USE_KHR;
    }
    ```

The issue here is the resetting of the defaults. Once I set a hint I wouldn't expect it to get unset without me specifically requesting it. I came across the issue when adding Dear ImGui to my project. I set some hints and then Dear ImGui would create a window with `glfwCreateWindowSurface` and it would fail assertions in `vulkan.c` due to the `GLFW_CLIENT_API` hint being reset: ```c if (window->context.client != GLFW_NO_API) { _glfwInputError(GLFW_INVALID_VALUE, "Vulkan: Window surface creation requires the window to have the client API set to GLFW_NO_API"); return VK_ERROR_NATIVE_WINDOW_IN_USE_KHR; } ```

emidoots commented

2022-04-01 01:41:40 +00:00

(Migrated from github.com)

Aha! Okay, now I understand. So glfwCreateWindowSurface internally relies on window hints. I did not realize this.

The idea with hints being passed as a struct to glfw.Window.create is that it becomes stateless: you pass in the desired state, we ensure it's that, then we wipe the state away afterwards (just because that seemed clean)

But I see now that, actually, you sometimes need those window hints to be retained for longer periods of time.

In this case, I think that your suggestion of "don't reset hints after window creation" sounds good to me (in addition to exposing a method to reset them) - this way we keep the stateless aspect of glfw.Window.create on it's own, and just leave the window hints in a "dirty" state.

Aha! Okay, now I understand. So `glfwCreateWindowSurface` internally relies on window hints. I did not realize this. The idea with hints being passed as a struct to `glfw.Window.create` is that it becomes stateless: you pass in the desired state, we ensure it's that, then we wipe the state away afterwards (just because that seemed clean) But I see now that, actually, you sometimes need those window hints to be retained for longer periods of time. In this case, I think that your suggestion of "don't reset hints after window creation" sounds good to me (in addition to exposing a method to reset them) - this way we keep the stateless aspect of `glfw.Window.create` on it's own, and just leave the window hints in a "dirty" state.

prime31 commented

2022-04-01 04:55:47 +00:00

(Migrated from github.com)

That sounds perfecto!

👍 1