So far you can see the XCode console window reports the collisions between the player and moving target. 
Now is time to add some sound. Audio is not integrated into Cocos2D and so a library is required. Fortunately CocosDenshion is an audio library with IOS gaming in mind and is a part of Kobold2D. CocosDenshion is referred to as SimpleAudioEngine in the code.
The file format for playing background sound with CocosDenshion is mp3. For short sound effects, the format recommendation is 16 bit mono wave files for uncompressed audio and IMA4 for lossy compressed audio. You can read more on formats and sound quality choices at CocosDenshion .
Lesson Downloads
- Game piece images and sound for project
- IPhone images for project. Icons and splash screen.
- Completed Project. This is built in Kobold2d 1.0.1.
Step 1 – Build an Empty-Project Template
You can continue with the Lesson 5 project and make changes noted here. Otherwise the steps for creating this project from an Empty-Project template are the same as Lesson 1 except to substitute Lesson 6 for Lesson 1 in the project name and to include the red_ball.png, red_ball-hd.png and explosion.caf files when you add the game pieces. The explosion.caf goes in same group as the images. Then you can use the code presented here.
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Step 2 – Set Properties in config.lua
There are no new configuration properties from Lesson 5. Complete config.lua file is included here for your copy convenience.
--[[
* Kobold2D™ --- http://www.kobold2d.org
*
* Copyright (c) 2010-2011 Steffen Itterheim.
* Released under MIT License in Germany (LICENSE-Kobold2D.txt).
--]]
--[[
* Need help with the KKStartupConfig settings?
* ------ http://www.kobold2d.com/x/ygMO ------
--]]
local config =
{
KKStartupConfig =
{
-- load first scene from a class with this name, or from a Lua script with this name with .lua appended
FirstSceneClassName = "GameLayer",
-- set the director type, and the fallback in case the first isn't available
DirectorType = DirectorType.DisplayLink,
DirectorTypeFallback = DirectorType.NSTimer,
MaxFrameRate = 60,
DisplayFPS = YES,
EnableUserInteraction = YES,
EnableMultiTouch = NO,
-- Render settings
DefaultTexturePixelFormat = TexturePixelFormat.RGBA8888,
GLViewColorFormat = GLViewColorFormat.RGB565,
GLViewDepthFormat = GLViewDepthFormat.DepthNone,
GLViewMultiSampling = NO,
GLViewNumberOfSamples = 0,
Enable2DProjection = NO,
EnableRetinaDisplaySupport = YES,
EnableGLViewNodeHitTesting = NO,
EnableStatusBar = NO,
-- Orientation & Autorotation
DeviceOrientation = DeviceOrientation.LandscapeLeft,
AutorotationType = Autorotation.None,
ShouldAutorotateToLandscapeOrientations = NO,
ShouldAutorotateToPortraitOrientations = NO,
AllowAutorotateOnFirstAndSecondGenerationDevices = NO,
-- Ad setup
EnableAdBanner = NO,
PlaceBannerOnBottom = YES,
LoadOnlyPortraitBanners = NO,
LoadOnlyLandscapeBanners = NO,
AdProviders = "iAd, AdMob", -- comma seperated list -> "iAd, AdMob" means: use iAd if available, otherwise AdMob
AdMobRefreshRate = 15,
AdMobFirstAdDelay = 5,
AdMobPublisherID = "YOUR_ADMOB_PUBLISHER_ID", -- how to get an AdMob Publisher ID: http://developer.admob.com/wiki/PublisherSetup
AdMobTestMode = YES,
-- Mac OS specific settings
AutoScale = NO,
AcceptsMouseMovedEvents = NO,
WindowFrame = RectMake(1024-640, 768-480, 640, 480),
EnableFullScreen = NO,
},
}
return config
Step 3 – GameLayer.h
There are no changes from Lesson 5 so the entire code is here for your copy and paste convenience.
/*
* Kobold2D™ --- http://www.kobold2d.org
*
* Copyright (c) 2010-2011 Steffen Itterheim.
* Released under MIT License in Germany (LICENSE-Kobold2D.txt).
*/
#import "kobold2d.h"
@interface GameLayer : CCLayer
{
CCSprite* player;
CGPoint playerVelocity;
CCSprite* movingTarget;
float movingTargetMoveDuration;
int totalAttempts;
int totalHits;
}
@end
Step 4 – Include the SimpleAudioEngine Library
Complete GameLayer.m file is included here for your copy convenience. I will focus on the code changes to accommodate the collision sounds.
/*
* Kobold2D™ --- http://www.kobold2d.org
*
* Copyright (c) 2010-2011 Steffen Itterheim.
* Released under MIT License in Germany (LICENSE-Kobold2D.txt).
*/
#import "GameLayer.h"
#import "SimpleAudioEngine.h"
@interface GameLayer (PrivateMethods)
-(void) initMovingTarget;
-(void) movingTargetUpdate:(ccTime)delta;
-(void) startMovingTargetSequence;
-(void) endMovingTargetSequence;
-(void) checkForCollision;
@end
// Velocity deceleration
const float deceleration = 0.4f;
// Accelerometer sensitivity (higher = more sensitive)
const float sensitivity = 6.0f;
// Maximum velocity
const float maxVelocity = 100.0f;
@implementation GameLayer
-(id) init
{
if ((self = [super init]))
{
// Enable accelerometer input events.
[KKInput sharedInput].accelerometerActive = YES;
[KKInput sharedInput].acceleration.filteringFactor = 0.2f;
// Preload the sound effect into memory so there's no delay when playing it the first time.
[[SimpleAudioEngine sharedEngine] preloadEffect:@"explosion.caf"];
// Initialize the total attempts to hit a moving target.
totalAttempts = 0;
// Initialize the total hits
totalHits = 0;
// Graphic for player
player = [CCSprite spriteWithFile:@"green_ball.png"];
[self addChild:player z:0 tag:1];
// Position player
CGSize screenSize = [[CCDirector sharedDirector] winSize];
float imageHeight = [player texture].contentSize.height;
player.position = CGPointMake(screenSize.width / 2, imageHeight / 2);
glClearColor(0.1f, 0.1f, 0.3f, 1.0f);
// First line of title
CCLabelTTF* label = [CCLabelTTF labelWithString:@"Kobold2d Intro Tutorial"
fontName:@"Arial"
fontSize:30];
label.position = [CCDirector sharedDirector].screenCenter;
label.color = ccCYAN;
[self addChild:label];
// Second line of title
CCLabelTTF* label2 = [CCLabelTTF labelWithString:@"Lesson 6"
fontName:@"Arial"
fontSize:24];
label2.color = ccCYAN;
label2.position = CGPointMake([CCDirector sharedDirector].screenCenter.x ,label.position.y - label.boundingBox.size.height);
[self addChild:label2];
// Seed random number generator
srandom((UInt32)time(NULL));
// Initialize our moving target.
[self initMovingTarget];
// Start animation - the update method is called.
[self scheduleUpdate];;
}
return self;
}
-(void) dealloc
{
#ifndef KK_ARC_ENABLED
[super dealloc];
#endif // KK_ARC_ENABLED
}
#pragma mark Player Movement
-(void) acceleratePlayerWithX:(double)xAcceleration
{
// Adjust velocity based on current accelerometer acceleration
playerVelocity.x = (playerVelocity.x * deceleration) + (xAcceleration * sensitivity);
// Limit the maximum velocity of the player sprite, in both directions (positive & negative values)
if (playerVelocity.x > maxVelocity)
{
playerVelocity.x = maxVelocity;
}
else if (playerVelocity.x < -maxVelocity)
{
playerVelocity.x = -maxVelocity;
}
}
#pragma mark update
-(void) update:(ccTime)delta
{
// Gain access to the user input devices / states
KKInput* input = [KKInput sharedInput];
[self acceleratePlayerWithX:input.acceleration.smoothedX];
// Accumulate up the playerVelocity to the player's position
CGPoint pos = player.position;
pos.x += playerVelocity.x;
// The player constrainted to inside the screen
CGSize screenSize = [[CCDirector sharedDirector] winSize];
// Half the player image size player sprite position is the center of the image
float imageWidthHalved = [player texture].contentSize.width * 0.5f;
float leftBorderLimit = imageWidthHalved;
float rightBorderLimit = screenSize.width - imageWidthHalved;
// Hit left boundary
if (pos.x < leftBorderLimit)
{
pos.x = leftBorderLimit;
// Set velocity to zero
playerVelocity = CGPointZero;
}
// Hit right boundary
else if (pos.x > rightBorderLimit)
{
pos.x = rightBorderLimit;
// Set velocity to zero
playerVelocity = CGPointZero;
}
// Move the player
player.position = pos;
// Collision check
[self checkForCollision];
}
#pragma mark MovingTarget
-(void) initMovingTarget
{
NSLog(@"initMovingTarget");
// This is the image
movingTarget = [CCSprite spriteWithFile:@"red_ball.png"];
// Add CCSprite for movingTarget
[self addChild:movingTarget z:0 tag:2];
// Set the starting position and start movingTarget play sequence
[self startMovingTargetSequence];
movingTargetMoveDuration = 4.0f;
// Unschedule the selector just in case. If it isn't scheduled it won't do anything.
[self unschedule:@selector(movingTargetUpdate:)];
// Schedule the movingTarget update logic to run at the given interval.
[self schedule:@selector(movingTargetUpdate:) interval:0.1f];
}
-(void) startMovingTargetSequence
{
NSLog(@"startMovingTargetSequence");
// Increment total attempts to hit a moving target.
totalAttempts ++;
// Get the window size
CGSize screenSize = [[CCDirector sharedDirector] winSize];
// Get the image size
CGSize imageSize = [movingTarget texture].contentSize;
// Generate a random x starting position with offsets for center registration point.
int randomX = CCRANDOM_0_1() * (screenSize.width / imageSize.width);
movingTarget.position = CGPointMake(imageSize.width * randomX + imageSize.width * 0.5f, screenSize.height + imageSize.height);
// Schedule the movingTarget update logic to run at the given interval.
[self schedule:@selector(movingTargetUpdate:) interval:0.1f];
}
-(void) movingTargetUpdate:(ccTime)delta
{
// CCSprite->CCNode no sequence of actions running.
if ([movingTarget numberOfRunningActions] == 0)
{
NSLog(@"movingTargetUpdate");
// Determine below screen position.
CGPoint belowScreenPosition = CGPointMake(movingTarget.position.x, - ( [movingTarget texture].contentSize.height));
// CCAction to move a CCNode object to the position x,y based on position.
CCMoveTo* moveEnd = [CCMoveTo actionWithDuration:movingTargetMoveDuration position:belowScreenPosition];
// Call back function for the action.
CCCallFuncN* callEndMovingTargetSequence = [CCCallFuncN actionWithTarget:self selector:@selector(endMovingTargetSequence)];
// Create a sequence, add the actions: the moveEnd CCMoveTo and the call back function for the end position.
CCSequence* sequence = [CCSequence actions:moveEnd,callEndMovingTargetSequence, nil];
// Run the sequence.
[movingTarget runAction:sequence];
}
}
-(void) endMovingTargetSequence
{
NSLog(@"endMovingTargetSequence");
[movingTarget stopAllActions];
// Terminate running the moveTargetUpdate interval.
[self unschedule:@selector(movingTargetUpdate:)];
// Decrease the moving target move duration to increase the speed.
movingTargetMoveDuration -= 0.1f;
// Moving target move duration is below 2 then hold at 2.
if (movingTargetMoveDuration < 2.0f)
{
movingTargetMoveDuration = 2.0f;
}
NSLog(@"movingTargetMoveDuration: %f",movingTargetMoveDuration);
// Set the starting position and start movingTarget play sequence
[self startMovingTargetSequence];
}
#pragma mark Collision Check
-(void) checkForCollision
{
// Size of the player and target. Both are assumed squares so width suffices.
float playerImageSize = [player texture].contentSize.width;
float targetImageSize = [movingTarget texture].contentSize.width;
// Compute their radii. Tweak based on drawing.
float playerCollisionRadius = playerImageSize *.4;
float targetCollisionRadius = targetImageSize *.4;
// This collision distance will roughly equal the image shapes.
float maxCollisionDistance = playerCollisionRadius + targetCollisionRadius;
// Distance between two points.
float actualDistance = ccpDistance(player.position, movingTarget.position);
// Are the two objects closer than allowed?
if (actualDistance < maxCollisionDistance)
{
// Play a sound effect
[[SimpleAudioEngine sharedEngine] playEffect:@"explosion.caf"];
totalHits++;
NSLog(@"HIT! Total attempts: %i. Total hits: %i", totalAttempts, totalHits);
[self endMovingTargetSequence];
}
}
@end
First the sound effect library is needed. Line 9 accomplishes that for you.
/* * Kobold2D™ --- http://www.kobold2d.org * * Copyright (c) 2010-2011 Steffen Itterheim. * Released under MIT License in Germany (LICENSE-Kobold2D.txt). */ #import "GameLayer.h" #import "SimpleAudioEngine.h" @interface GameLayer (PrivateMethods) -(void) initMovingTarget; -(void) movingTargetUpdate:(ccTime)delta; -(void) startMovingTargetSequence; -(void) endMovingTargetSequence; -(void) checkForCollision; @end
Step 5 – Preload the Collision Sound Effect
Next you can preload the sound effect file to avoid a delay the first time it is played. The init method is the perfect place to do the preloading and line 36 shows how it is done with SimpleAudioEngine.
-(id) init
{
if ((self = [super init]))
{
// Enable accelerometer input events.
[KKInput sharedInput].accelerometerActive = YES;
[KKInput sharedInput].acceleration.filteringFactor = 0.2f;
// Preload the sound effect into memory so there's no delay when playing it the first time.
[[SimpleAudioEngine sharedEngine] preloadEffect:@"explosion.caf"];
// Initialize the total attempts to hit a moving target.
totalAttempts = 0;
// Initialize the total hits
totalHits = 0;
// Graphic for player
player = [CCSprite spriteWithFile:@"green_ball.png"];
[self addChild:player z:0 tag:1];
// Position player
CGSize screenSize = [[CCDirector sharedDirector] winSize];
float imageHeight = [player texture].contentSize.height;
player.position = CGPointMake(screenSize.width / 2, imageHeight / 2);
glClearColor(0.1f, 0.1f, 0.3f, 1.0f);
// First line of title
CCLabelTTF* label = [CCLabelTTF labelWithString:@"Kobold2d Intro Tutorial"
fontName:@"Arial"
fontSize:30];
label.position = [CCDirector sharedDirector].screenCenter;
label.color = ccCYAN;
[self addChild:label];
// Second line of title
CCLabelTTF* label2 = [CCLabelTTF labelWithString:@"Lesson 6"
fontName:@"Arial"
fontSize:24];
label2.color = ccCYAN;
label2.position = CGPointMake([CCDirector sharedDirector].screenCenter.x ,label.position.y - label.boundingBox.size.height);
[self addChild:label2];
// Seed random number generator
srandom((UInt32)time(NULL));
// Initialize our moving target.
[self initMovingTarget];
// Start animation - the update method is called.
[self scheduleUpdate];;
}
return self;
}
Step 6 – Play the Collision Sound Effect
Playing the sound effect is done in the checkForCollision method and is a single line of code on line 215.
#pragma mark Collision Check
-(void) checkForCollision
{
// Size of the player and target. Both are assumed squares so width suffices.
float playerImageSize = [player texture].contentSize.width;
float targetImageSize = [movingTarget texture].contentSize.width;
// Compute their radii. Tweak based on drawing.
float playerCollisionRadius = playerImageSize *.4;
float targetCollisionRadius = targetImageSize *.4;
// This collision distance will roughly equal the image shapes.
float maxCollisionDistance = playerCollisionRadius + targetCollisionRadius;
// Distance between two points.
float actualDistance = ccpDistance(player.position, movingTarget.position);
// Are the two objects closer than allowed?
if (actualDistance < maxCollisionDistance)
{
// Play a sound effect
[[SimpleAudioEngine sharedEngine] playEffect:@"explosion.caf"];
totalHits++;
NSLog(@"HIT! Total attempts: %i. Total hits: %i", totalAttempts, totalHits);
[self endMovingTargetSequence];
}
}
You should be all set to hear crashes as you tilt your IPad or IPhone and try to intercept our falling target.
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