White screen after opening the app?

[xiaottang2]

I clone it with --recursive-submodules and built it successfully. During building, I encountered some errors:

src/Game.cpp:194:13: error: non-constant-expression cannot be
      narrowed from type 'double' to 'float' in initializer list
      [-Wc++11-narrowing]
        g.mouse = {x, y};

but I fixed them by adding static_cast<float>( ) to each x and y. It doesn't bother me.

But after I built it, and run it, it shows white screen like this:

[xiaottang2]

I am running macOS Sierra btw

[ddovod]

Maybe you should just copy spritesheet.png (can be found here http://www.spriters-resource.com/resources/sheets/56/59537.png) into the directory with your game executable