Cocos2D v3 CCParallaxNode scrolling can't keep player in focus

Question

I am very fresher to game development and I need to develop a game like NinjaJump.

I have created a CCParallaxNode to setup scrolling background and added CCPhysicsNode to setup Physics world. I have created player object as shown below.

// Add a sprite
    _sprite = [CCSprite spriteWithImageNamed:@"Icon.png"];
    _sprite.position  = ccp(self.contentSize.width/2,100);
    _sprite.physicsBody = [CCPhysicsBody bodyWithRect:(CGRect){CGPointZero, _sprite.contentSize} cornerRadius:0.0];
    _sprite.physicsBody.friction = 0.0f;
    _sprite.physicsBody.collisionGroup = @"player";
    _sprite.physicsBody.collisionType = @"Player";
    //_sprite.physicsBody.collisionMask = 0;
    //[self addChild:_sprite];
    [foreground addChild:_sprite];

foreground is just a node added into CCScene to easily manage player in-focus.

// code for physics world
_physicsWorld = [CCPhysicsNode node];
    _physicsWorld.gravity = ccp(0,-100);
    _physicsWorld.debugDraw = YES;
    //_physicsWorld.collisionDelegate = self;
    [self addChild:_physicsWorld];

    _foreground = [CCNode node];
    //[self addChild: _foreground];
    [_physicsWorld addChild: _foreground];

To make player always visible we have implemented update method as

- (void) update:(CFTimeInterval)currentTime {
    // Calculate player y offset
    if (_player.position.y > 200.0f) {
        //_midgroundNode.position = CGPointMake(0.0f, -((_player.position.y - 200.0f)/4));
        _foreground.position = CGPointMake(0.0f, -(_player.position.y - 200.0f));
    }
}

I can't understand but the player scrolls off screen anyhow. The code is written in Cocos2d v3.

I have also setup a demo project to show what I implemented: https://www.dropbox.com/s/5s55d00kk80wun4/HumptyJump-Example.zip?dl=0

Any kind of help is appreciated. Thanks in advance.

score 0 · Answer 1 · answered Oct 12 '14 at 15:44

0

I could not run your sample code but one thing, I can tell you for sure that there is no need of Physics Engine here.

You just keep your player at a particular height and just move your object right to left. Apply moving parallax background image and objects to give a feel that your character is moving upwards or downwards.

For reference you can see the games like Swing Drop, made on the same approach as above.

answered Oct 12 '14 at 15:44

Shoaib

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Thanks dear but I am also going to implement some obstacles through which my player battles across, might this require physics engine. But I will try implement the solution you said. – Paresh Thakor Oct 12 '14 at 16:48
If you are using physics engine only for collision detection, so again I would not recommend to use physics engine. You can do collision detection by just comparing bounds of the sprites. The reference game I shared doing the same. Even You can use physics engine too but not at least like you are doing right now. your PlatformNode is pushing your player very hard when you start moving your foreground node and it goes out of the screen. – Shoaib Oct 13 '14 at 05:38

score 0 · Accepted Answer · answered Oct 23 '14 at 11:25

I have implemented 2 fixed views changing their positions while physics body goes down ;).

See the same in action

@interface TestScene () {
    CCNode *_background;
    CCNode *_foreground;

    NSArray *grounds; // Keeps track of each of the 2 views
    CCPhysicsNode *_physicsWorld;
}

@implementation TestScene

- (id)init {
    self = [super init];
    if (!self) return(nil);

    // Enable touch handling on scene node
    self.userInteractionEnabled = YES;

    // Physics world setup
    _physicsWorld = [CCPhysicsNode node];
    _physicsWorld.gravity = ccp(0,-100);
    _physicsWorld.debugDraw = YES;
    _physicsWorld.collisionDelegate = self;
    [self addChild:_physicsWorld];

    // Foreground node in which platforms are there and moves downwards as player goes up
    _foreground = [CCNode node];

    // Adding background images
    CCSprite *default1 = [CCSprite spriteWithImageNamed: @"Default.png"];
    [default1 setAnchorPoint: ccp(0, 0)];
    CCSprite *default2 = [CCSprite spriteWithImageNamed: @"Default.png"];
    [default2 setAnchorPoint: ccp(0, 0)];
    [default2 setPosition: ccp(0, default1.contentSize.height)];
    [_foreground addChild: default1];
    [_foreground addChild: default2];

    // Adding into array
    grounds = @[default1, default2];
    // Adding into physics world
    [_physicsWorld addChild: _foreground];

    // creating player
    _player = [CCSprite spriteWithImageNamed: @"Assets.atlas/Player.png"];
    [_player setPosition: ccp(160.0f, 160.0f)];
    _player.physicsBody = [CCPhysicsBody bodyWithRect:(CGRect){CGPointZero, _player.contentSize} cornerRadius:0]; // 1
    _player.physicsBody.collisionGroup = @"playerGroup"; // 2
    _player.physicsBody.collisionType = @"player";
    //[_physicsWorld addChild:_player];
    [_foreground addChild: _player];

    // Multiple platforms can be added into body, they are static entities only
    PlatformNode *platform = (PlatformNode *)[PlatformNode node];
    [platform createPlatformAtPosition:CGPointMake(110, 50) ofType: PLATFORM_NORMAL];
    [_foreground addChild: platform];

    return self;
}

- (void) update:(CFTimeInterval)currentTime {
    // Take background and physics world down, 163 was Y position of the player
    _physicsWorld.position = ccp(_physicsWorld.position.x, 163 - _player.position.y);

    // loop the ground
    for (CCNode *ground in grounds) {
        // Get the world position
        CGPoint groundWorldPosition = [_physicsWorld convertToWorldSpace: ground.position];
        // Get screen position
        CGPoint groundScreenPosition = [self convertToNodeSpace: groundWorldPosition];
        NSLog(@"Positioning ground ---> world: (%f, %f) & screen: (%f, %f)", groundWorldPosition.x, groundWorldPosition.y, groundScreenPosition.x, groundScreenPosition.y, nil);
        if (groundScreenPosition.y <= -ground.contentSize.height) {
            ground.position = ccp(ground.position.x, ground.position.y + 2 * ground.contentSize.height);
            break;
        }
    }
}

-(void) touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
    // Take the player upside
    [_player.physicsBody applyImpulse: ccp(0, 215)];
}

@end

This is how I coded the background :).

Cocos2D v3 CCParallaxNode scrolling can't keep player in focus

2 Answers2