var rain_handle_snd = 0; // pointer to the rain sound
var rain_volume_snd = 0; // volume of the rain sound

SOUND* rain_wav = "rain.wav"; // rain sound file itself

function handle_rain(){
	// play rain sound in a loop:
	rain_handle_snd = snd_loop(rain_wav, 0, 0);
	// endless while loop:
	while(1){
		// if we need to increase it:
		if(rain_volume_snd < 50){
			// then increase it:
			rain_volume_snd += 2 * time_step;
		}
		// tune the volume of the rain:
		snd_tune(rain_handle_snd, rain_volume_snd, 0, 0);
		// wait one frame:
		wait(1);
	}
}

action fucking_river(){
     ent_playloop(my, river_fucking_sound, 500); // play with 500 
}