Use {Get,Set}WindowLongPtr() instead of a global lookup table

[tilkinsc]

Hello, I was watching your video.

It appears you created a global lookup table 'pmap' which you use to convert a hWnd into muCOSA specific data.

https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowlongptrw
For each window, you can store a pointer into GWLP_USERDATA via SetWindowLongPtrW(hWnd, GWLP_USERDATA, LONG_PTR);.

Quote,
Certain window data is cached, so changes you make using SetWindowLongPtr will not take effect until you call the SetWindowPos function.

// window creation/whenever you feel like it
SetWindowLongPtr(hWnd, GWLP_USERDATA, (LONG_PTR) muCOSA);
SetWindowPos(hWnd, NULL, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);

...

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static muCOSA_struct window = NULL;
    window = (muCOSA_struct*) GetWindowLongPtr(hWnd, GWLP_USERDATA);
    ....
}

This is a game changer in how your API handles.

Excited to see where your API takes you, as I am unifying linux/mac/windows for rendering but exposing the OS specific stuff while I am at it under a higher and lower order library.