CODEWITHSUNDEEP
iosobjectscreensprite-kit
Kevin Tarr
Kevin Tarr

Reputation: 387

iOS game moving object up and down

I am trying to create a game, something slightly similar to Jetpack Joyride. At certain points it will have an object that the player has to fly between - like the pipes on flappy birds. I have managed to create the pipe objects however I wish for the objects to move up and down on the screen, making it harder for the player to jump between. My code for placing the objects is:

// Maths
float availableSpace = HEIGHT(self) - HEIGHT(floor);
float maxVariance = availableSpace - (2*OBSTACLE_MIN_HEIGHT) - VERTICAL_GAP_SIZE;
float variance = [Math randomFloatBetween:0 and:maxVariance];

// Bottom object placement
float minBottomPosY = HEIGHT(floor) + OBSTACLE_MIN_HEIGHT - HEIGHT(self);
float bottomPosY = minBottomPosY + variance;
bottomPipe.position = CGPointMake(xPos,bottomPosY);
bottomPipe.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:CGRectMake(0,0, WIDTH(bottomPipe) , HEIGHT(bottomPipe))];
bottomPipe.physicsBody.categoryBitMask = blockBitMask;
bottomPipe.physicsBody.contactTestBitMask = playerBitMask;

// Top object placement
topPipe.position = CGPointMake(xPos,bottomPosY + HEIGHT(bottomPipe) + VERTICAL_GAP_SIZE);
topPipe.physicsBody = [SKPhysicsBody bodyWithEdgeLoopFromRect:CGRectMake(0,0, WIDTH(topPipe), HEIGHT(topPipe))];

topPipe.physicsBody.categoryBitMask = blockBitMask;
topPipe.physicsBody.contactTestBitMask = playerBitMask;

How would I go about moving the objects up and down? Thanks for any help :)

Upvotes: 0

Views: 551

Answers (1)

ZeMoon
ZeMoon

Reputation: 20274

All such operations on a node are done using SKAction objects. Read up on the SKAction class here.

In your case, using an SKAction to move the nodes up and down would go something like this:

SKAction *actionMoveUp = [SKAction moveByX:0 y:20 duration:0.5];
SKAction *actionMoveDown = [actionMoveUp reversedAction];
SKAction *actionMoveUpDown = [SKAction sequence:@[actionMoveUp, actionMoveDown]];
SKAction *actionMoveDownRepeat = [SKAction repeatActionForever:actionMoveUpDown]; 

[bottomPipe runAction:actionMoveDownRepeat];
[topPipe runAction:actionMoveDownRepeat];

The code given above will make your top and bottom pipe go up and down by a factor of 20 pixels repeatedly.

Upvotes: 2

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