a simple program

If you are using the template then you already have a minimum main.cpp file that should look something like this:

#include "engine.h"

int main (int argv, char** args) {
    fresa::run();
    return 0;
}

All you need to run fresa is to import the engine header and call fresa::run().

If you wish to configure how the engine behaves, you can look into the configuration file and into the system manager.

hello world

For this example we are going to use a simple system with an init() function, which will execute its code when the engine is initialized. We will create a hello_world.h file and define this system as so:

hello_world.h

#pragma once
#include "system.h"

namespace fresa
{
    struct SomeSystem {
        inline static System<SomeSystem> system; //: this line registers the system

        static void init() {
            //: your code goes here
        }
    };
}

You also need to include it inside main.cpp:

main.cpp

#include "engine.h"
#include "hello_world.h"

//... other code

Now, we can import the logging library and use it to print a message when the callback is executed:

hello_world.h

#include "engine.h"
#include "log.h"

//... other code

static void init() {
    log::info("hello world!");
}

If you execute the program now, you will see the message printed in the terminal.