What could possibly go wrong?

I recently read a blogpost about compile-time string-hashes and constexpr and I’m still not convinced and see no real reason to leave my old and true friend the script :)

So first of lets look at the problem we want to solve. We want a way to do things like this and not pay the runtime cost ( and in this case just compile! ).

void my_func( uint32_t val )
{
    switch( val )
    {
        case HashOfString("some_string"):
            do_some_stuff();
            break;
        case HashOfString("some_other_string"):
            do_some_other_stuff();
            break;
    }
}

Simple enough. What seems to come up over and over again is ways of doing this with the compiler compile-time and now recently just marking HashOfString as constexpr and “trust the compiler”. The solution I usually fall back to is to just have a text-file where each line is hashed with a custom script and written to a .h file with values such as:

I like command-line arguments as mentioned in an earlier post about them. In this post I’ll discuss a method to use them as simple config-files.

Let’s start of with a usage example from my own code. I have a meshviewer/particleviewer that is used for, you guessed it, viewing meshes and particle-effects. These kind of resources, at least the particle-effects, have internal paths to resources that need to be read while loading ( particles have a material to be rendered with etc ), i.e. resources from “some game” need to be found by the particle-viewer. Since reading resources is done via a VFS ( Virtual File System ) and paths is always specified via this VFS in resources we must just make sure that “some game”:s resources is mounted in the particle-viewer!

I really like using command line arguments. I think that it is a flexible way to interact with and configure my games/engine. It is for example easier to just add a --log-verbose=resource to set all logging in the “resource”-domain to verbose or --memory-enable-stacktrace=render to enable save of stacktraces for all allocations done in the “render”-allocator than to edit some config-file somewhere. At least for things such as the ones mentioned above, that is only set once in a while.