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The CCSpawn action lets you run several actions at the same time. The duration of the CCSpawn action will be the duration of the longest sub-action.
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id action = [CCSpawn actions: [CCJumpBy actionWithDuration:2 position:ccp(300,0) height:50 jumps:4], [CCRotateBy actionWithDuration: 2 angle: 720], nil]; [sprite runAction:action]; |
The CCSpeed action modifies the duration of the inner action.
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id move = [CCMoveBy actionWithDuration:3 position:ccp(350,0)]; id action = [CCSpeed actionWithAction: move speed:1.0f]; // no speed modification // but you can modify the speed later [action setSpeed: 2.5f]; // speed is 2.5 faster [action setSpeed: 0.5f]; // speed is 0.5 faster (it means 2 times slower) |
@synthesize will generate getter and setter methods for your property. @dynamic just tells the compiler that the getter and setter methods are implemented not by the class itself but somewhere else (like the superclass)
Uses for @dynamic are e.g. with subclasses of NSManagedObject (CoreData) or when you want to create an outlet for a property defined by a superclass that was not defined as an outlet:
Super class:
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@property (nonatomic, retain) NSButton *someButton; ... @synthesize someButton; |
Subclass:
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@property (nonatomic, retain) IBOutlet NSButton *someButton; ... @dynamic someButton; |
There are two variations of CCCallFunc. They are CCCallFuncN and CCCallFuncND.
CCCallFuncN takes the node as an argument, and CCCallFuncND takes the node and a pointer to some data.
For example:
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id actionCallFuncN = [CCCallFuncN actionWithTarget:self selector:@selector(doATaskN:)]; // make sure you notice the trailing : id actionCallFuncND = [CCCallFuncND actionWithTarget:self selector:@selector(doATaskND:data:) data:pointerToSomeData]; - (void) doATaskN: (id)node { //some code } - (void) doATaskND: (id)node data:(void*)d { //some code } |
Action that has the ’3D’ suffix in their names, means that they produce a 3D visual effects by modifying the z-coordinate of the grid.
If you’re going to use any ’3D’ action, probably you will want to use the depth buffer. An easy way to do that is by calling:
// IMPORTANT: Call this function at the very beginning, before running your 1st scene
// Create a depth buffer of 24 bits
// These means that openGL z-order will be taken into account
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[[CCDirector sharedDirector] setDepthBufferFormat:kDepthBuffer16]; |
And under some circumstances, you might also want to set an RGBA8888 pixel format. This will let you have effects with transparency
// IMPORTANT: Call this function at the very beginning, before running your 1st scene
// Use this pixel format to have transparent buffers
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[[CCDirector sharedDirector] setPixelFormat:kPixelFormatRGBA8888]; |
You can use this code to save an image in the file.
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UIImage *bobImage = [UIImage imageNamed:@"Bob.png"];//creating an object for the image. NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);//creating the file path. NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *Imgpath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"imgFile.png"]]; CGSize size = CGSizeMake(120, 120);//creating a rect for the image. UIGraphicsBeginImageContext(size); [bobImage drawInRect:CGRectMake(0, 0, 120, 120)];//drawing img in the rect. bobImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); NSData *data = UIImagePNGRepresentation(bobImage); [data writeToFile:Imgpath atomically:YES];//writing image to the file. |
It is possible to convert GL point to UITouch point in cocos2D using the following code :
Consider a GL point, glLocation.
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CGPoint location = [[CCDirector sharedDirector] convertToUI: glLocation]; |
// Now location will contain the UITouch point corresponding to GL point, glLocation.
So far, we have been replacing scenes like this:
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[[Director sharedDirector] replaceScene:[PlayScene node]]; |
Fortunately, cocos2d comes with a whole slew of cheesy transitions. We’ll find all the transitions listed in the Transitions.h file in the cocos2d folder.
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[TransitionClassName transitionWithDuration:(ccTime)t scene:(Scene *)s]; |
The interesting thing about calling this method is that it returns an instance of TransitionScene, which extends Scene and contains the scene you passed into it. So you can use this method directly in the call to Director’s replaceScene, or any other scene changing method.
To draw a line in cocos2d, you can use the following code :
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- (void)draw { [super draw]; glColor4ub(0,0,0,255); glLineWidth(2); ccDrawLine(ccp(x1,y1), ccp(x2,y2)); } |
(Write this function in your code. This function will be called automatically. You just need to put the values for x1,y1,x2 & y2.)
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-(void) draw { glEnable(GL_LINE_SMOOTH); glColor4ub(255, 0, 255, 255); glLineWidth(2); CGPoint vertices2[] = { ccp(50,320), ccp(280,320), ccp(280,250), ccp(50,250) }; ccDrawPoly(vertices2, 4, YES); } |
Write this function in your code.This function will be called automatically.Change the value of the vertices to vary the size of the rectangle.
