UFCEKU-20-3Web Games Programming Game Sound

UFCEKU-20-3Web Games Programming Agenda Motivation for using Sound in Games Typical Game Sound Scenarios Acquiring, Editing and Creating Sound Using Sound in ActionScript 3.0 Techniques for Managing Sound in Games Sound Editing Software

UFCEKU-20-3Web Games Programming Motivation for using Sound in Games Sound greatly enhances user’s engagement with game through feedback on game action and events and general ambience. Sounds include Ambient sound - indicate setting to audience (background sound effects) Event sound - sprite collisions - game start and end music, level sounds (hard sound effects) Sound effects added to convey the scenario - physical noise footsteps (foley sound effects) Sound not present in nature and impossible to record such as futuristic sounds (design sound effects) Sound is either Audio or Music Audio - digitally sampled sound in various formats Music generally refers to MIDI-based sound - good for backdrop to game - limited by onboard sound device - synthesized sound not as authentic as audio

UFCEKU-20-3Web Games Programming Audio Sound Characteristics Audio samples in specific format Resolution (bits), sample rate (hertz), mono or stereo More bits, higher sample rate and stereo is best Compact Disc ‘Red Book Audio’ is = samples/s × 16 bit/sample × 2 channels Balance between sound quality and file size Low quality sound easily identified by listener - as compared with low quality visuals - e.g video - viewer more forgiving of lower quality visuals than sound

UFCEKU-20-3Web Games Programming Popular Sound Formats Sound formats include.wav,.aif,.mp3,.snd,.wav - ‘wave’ not ‘wav’ (Waveform Audio Format) Lossless uncompressed format best for retaining ‘first generation’ high quality audio sound libraries

UFCEKU-20-3Web Games Programming Acquiring, Editing and Creating Sound Websites see e.g Get sound from genre specific or tribute sites Purchase CD library material (BBC sound archives) Create you own with audio software Usually need to edit and compress to use in game scenario

UFCEKU-20-3Web Games Programming Sound with ActionScript 3.0 Supports sound for audio with the Sound class SoundChannel class and SoundTransform class Embedded audio and external audio Embedded audio includes many of the popular formats.wav,.aif External audio must be in the.mp3 format The Sound class provides the facilitates for loading and playing audio. An audio instance may be modified by accessing properties via the SoundTransform class to modify left and right volume levels and pause playback. Supports up to 32 simultaneous channels

UFCEKU-20-3Web Games Programming Sound with ActionScript 3.0 // set up buttons button1.addEventListener(MouseEvent.CLICK, playLibrarySound); button2.addEventListener(MouseEvent.CLICK, playExternalSound); // load external sound so it is ready var soundTwo:Sound = new Sound(); var externalSoundFile:URLRequest = new URLRequest("PlayingSounds.mp3"); soundTwo.load(externalSoundFile); // function to play the library sound function playLibrarySound(event:Event) { var soundOne:SoundOne = new SoundOne(); var channel:SoundChannel = soundOne.play(); } // function to play the external sound function playExternalSound(event:Event) { soundTwo.play(); }

UFCEKU-20-3Web Games Programming Adjusting Sound Volume // load external sound file into a sound object var aSound:Sound = new Sound(new URLRequest(song.mp3)); // create a sound channel based on the loaded sound var soundChannelOne:SoundChannel = aSound.play(); //create a sound channel transform (adjuster) var channelOneControl:SoundTransform = new SoundTransform(); // use the transform to adjust volume level channelOneControl.volume =.5 // (0-1); // assign this adjustment to the sound channel associated with song.mp3 soundChannelOne.soundTransform = channelOneControl; What a Mission!

UFCEKU-20-3Web Games Programming Techniques for Managing Sound in Games Load audio into an array and play random sounds for events to add variety Implement the notion of spatialized sound by increasing / decreasing the volume as objects change their proximity to each other

UFCEKU-20-3Web Games Programming // create an array to hold the sounds var eventSounds:Array = new Array; // create five sound variables var soundOne:Sound = new Sound(); var soundTwo:Sound = new Sound(); var soundThree:Sound = new Sound(); var soundFour:Sound = new Sound(); var soundFive:Sound = new Sound(); // create variables for the external audio files var externalSoundFile1:URLRequest = new URLRequest("./mp3/alert.mp3"); var externalSoundFile2:URLRequest = new URLRequest("./mp3/alarm.mp3"); var externalSoundFile3:URLRequest = new URLRequest("./mp3/warning.mp3"); var externalSoundFile4:URLRequest = new URLRequest("./mp3/ambient_one.mp3"); var externalSoundFile5:URLRequest = new URLRequest("./mp3/ambient_two.mp3"); //load the external audio into the sound variables soundOne.load(externalSoundFile1); soundTwo.load(externalSoundFile2); soundThree.load(externalSoundFile3); soundFour.load(externalSoundFile4); soundFive.load(externalSoundFile5); // place sounds into the array eventSounds[1] = soundOne; eventSounds[2] = soundTwo; eventSounds[3] = soundThree; eventSounds[4] = soundFour; eventSounds[5] = soundFive; // function to play random sounds from the array function playSound() { var randomNumber = getRandomNumber(5) eventSounds[randomNumber].play(0,0); // startTime, loops, }

UFCEKU-20-3Web Games Programming Sound Production Software Audacity (Editor) cross platform open source Excellent support for wide range of audio formats and encoding into.mp3 ( need lame encoder) MuLab (Sequencer and Synthesis) Cross platform with capable free versions 32 and 64 bit Windows versions Wide range of preset synthesized sounds including sequences and effects Supports VST plugins