When your game runs, and needs to load some assets from disk. ie:

spritesheet.loadFromFile("res/img/invaders_sheet.png")

It needs to be able to safely and reliably find those files. There are a few ways to go about this, and I’ll discuss them here.

Where should I put my files anyway?

I believe you should have your runtime assets set up as if the game were installed on a users PC; Inside the game’s folder, next to the .exe.

Our .exe lives inside the build folder, which we don’t version control or care about. So we need to keep the assets somewhere safe, and either copy them over to the build folder or change the working directory to the source folder (Yuck. This is what VS does by default), or even hardcode the paths (Don’t ever do this)

Differences from running in VS, and running the .exe

When you complile your game, it build a .exe somewhere.

We set this in the cmake here SET(OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin/") .

So it should be something like C:/users/YOU/Desktop/GAMEBUILD/Release/game.exe .

Release and debug configurations should get their own subfolder.

Running in VS

Pressing Debug, or start without debugging doesn’t just launch the .exe, it wraps some Visual studio magic around it to catch exceptions, debug memory leaks, and inspect performance. It also by default Changes the working directory. The working directory is the directory the game will look to as it’s default path for files.

Running the .exe yourself

If you go find the exe and click on it, the working directory should be the same directory the .exe lives in. [Note: mac users, osx is backwards and complicated and may not do this, good luck]

Ok, So how do I do it?

Method 1 - The wrong way - Hardcoded paths

You’re an absolute madman, your game never needs to work on another PC.

spritesheet.loadFromFile("C:/users/YOU/Desktop/GAMEBUILD/Release/res/img/invaders_sheet.png")

This will work great, and is useful for debugging issues, but don’t have this as a permanent solution.

Method 2 - Change Working Dir, copy files from source to build

set_target_properties(PRACTICAL_2_INVADERS 
    PROPERTIES VS_DEBUGGER_WORKING_DIRECTORY
    ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/$(Configuration)
)

So when we run our game in VS it will look for file in the build folder, just as if we went and ran the .exe ourselves.

But we still haven’t got our resources in the build folder yet, they are still in the source folder. We could build some sort of batch script to do this, but we can tap into some Cmake magic to wrap this all up into our build and compile step.

Copy all resources via Custom CMake Target

CMake can add more than just executables to the solution, it can also add "custom targets". We just add below, and add a slightly modified version of our copy script within it.

add_custom_target(copy_resources ALL COMMAND ${CMAKE_COMMAND} 
  -E copy_directory
    "${PROJECT_SOURCE_DIR}/res"
    ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/$<CONFIGURATION>/res
)

Then for all of your projects, do:

 add_dependencies(PRACTICAL_2_INVADERS copy_resources)

If you need to trigger a copy, right click and build on the “copy_resources” project in VS.

If you are on osx, TODO