Why do I need to copy the DLL files to my executable directory?

The reason you need to copy the .dll files to your executable's directory (or another directory in the DLL search path) is due to the way Windows searches for DLLs at runtime.

When your application uses a DLL, Windows needs to locate that DLL file in order to load it into memory. It searches for the DLL in a specific order:

1. The directory from which the application loaded.
2. The system directory (e.g., C:\Windows\System32).
3. The 16-bit system directory (e.g., C:\Windows\System).
4. The Windows directory (e.g., C:\Windows).
5. The current directory.
6. The directories that are listed in the PATH environment variable.

So, if your .exe is in "C:\MyApp" and the .dll is in "C:\SDL2\lib\x64", Windows won't find the .dll unless "C:\SDL2\lib\x64" is in your PATH environment variable.

By copying the .dll to the same directory as your .exe, you ensure that Windows can always find the .dll, regardless of the PATH variable or other system settings.

For example, let's say your application is structured like this:

1MyApp/
2  MyApp.exe
3  SDL2.dll
4  Assets/
5    Player.png
6    Background.jpg

When you run MyApp.exe, Windows will:

1. Look for SDL2.dll in the same directory as MyApp.exe
2. Find it, since you copied it there
3. Load SDL2.dll into memory
4. Continue running your application

If you hadn't copied SDL2.dll, Windows would continue searching through the DLL search order, probably not find it, and give an error like:

1The code execution cannot proceed because SDL2.dll was not found.

So, while it may seem redundant to copy the .dlls, it's the most reliable way to ensure your application can always find its dependencies. This is especially important when distributing your application to others, as you can't control the setup of their system.