Here is a quick snippet that showed how classes are loaded in BriskLimbs, a video sharing project of mine
spl_autoload_register(function ($class) {
$class = ucfirst($class);
if (file_exists(MODEL_DIRECTORY . '/' . $class . '.php')) {
require_once MODEL_DIRECTORY . '/' . $class . '.php';
} else {
$class = strtolower($class);
if (file_exists(HELPERS_DIRECTORY . '/' . $class . '.php')) {
require_once HELPERS_DIRECTORY . '/' . $class . '.php';
} else {
exit(MODEL_DIRECTORY . '/' . $class . '.php');
exit('Error Loading Class File |' . $class . '| core:' . CORE_DIRECTORY);
}
}
});