ios - Creating a camera effect in Sprite Kit -

ios - Creating a camera effect in Sprite Kit -

i trying create game scrolls when user's touch close plenty top of iphone screen. have far:

-(void)update:(cftimeinterval)currenttime { cgpoint currentlocation = [currenttouch locationinview:currenttouch.view]; if (currentlocation.y > 100) { _world.position.y - 25; } }

so current location cgpoint derived touch registered in touchesbegan method. took y of (x doesn't matter don't think) , told scoot sknode in scene attached down. nil happening , warning 'the look result unused' during statement. i'm winging on one. ideas why doesn't work or improve solutions?

you not assign result of subtraction, result discarded:

_world.position.y - 25;

to assign new position:

cgfloat newy = _world.position.y - 25; _world.position = cgpointmake(_world.position.x, newy);

ios objective-c camera sprite-kit cgpoint