Moving the scene: SKAction animation or anchorPoint in update method?

Question

My game is based on two screens (A & B) side by side, but the device screen can only display one of them at a time.
A is for example at position (0, 0) and B is at (320, 0)

I tried two solutions to switch from A to B:

• First, I place the whole scene into one node, the MainNode. To switch from A to B, simply set MainNode position to (0, -320).
• Other solution, more elegant IMHO (but not for LearnCoco2D who uses the Coco2D library), is to move the scene anchorPoint to (0, -1)

Now, if I want to go from A to B with an animation, these two solutions must be adapted:

• By using a SKAction

  [Main runAction:[SKAction moveToY:-320 duration:0.1]];

• By animating anchorPoint in the update method

  if(anchorY > -1) anchorY -= 0.1;

These two solutions works (despite a linear SKAction::timingMode does not render a linear translation properly), but I wonder which is the best in term of optimization, and elegance. Documentation is welcomed ;)

EDIT:

Apparently, my question is not clear (maybe due to my english level).

In few words, my question is: What exactly are the best practices for scrolling a scene?

Answer 1

I am surprised (0, -1) doesn't throw a huge exception. According to the docs you get a range from 0 to 1. This could cause issues in the future. See the docs here

Changing your position sounds like a more elegant way of handling it. however changing it to negative -320 in a span of 1/10th of a second is rather quick and could explain why it looks funny. Also if you aren't making sure you are only calling that once it will look really odd. I would make sure that it is only getting called once and maybe using a bool to toggle if it should be moved instead of checking a position.

If you are going back and forth a lot from one screen to another this might be an ok solution. However if you are looking to scale this to a much larger map where you are going to transition several times to new screens I would recommend a different approach all together. Like creating a new node off screen when you need it and transition a parent node then pop the old node off.

I hope that helps.

Edit

Now that the question is "what exactly are the best practices for scrolling a scene".

I would recommend what LearnCoco2D mentioned in the comment and what I eluded to in my original answer.

• Add a sub node to your scene that will handle positioning (lets call it mapNode)
• Add any sprites that represent the scene to the mapNode
• Move just the MapNode position on update

In the past I have built my Scenes in a similar fashion and have handled the scene position based on the player position in the update loop. I was able to keep the player in the center of the screen as he walked around the map. Might be getting off subject, but that is what I found the best practice for handling scrolling a scene from my experience. The project I am working on can be viewed here

I hope that answers your question.