Before we move to the parallax effect logic, there is something I wanted to talk about related to the layering of our _gameBatchNode object, which you'll recall is a SpriteBatchNode object.

If you go to the static create method inside Terrain.cpp, you will notice that the object is still created with a reference to a blank.png texture:

terrain->initWithSpriteFrameName("blank.png")

In fact, the same 1 x 1 pixel image used in the test version is now in our sprite sheet, only this time the image is transparent.

This is a bit of a hack, but necessary, because a sprite can only be placed inside a batch node if its texture source is the same used to create the batch node. But Terrain is just a container, it has no texture. However, by setting its blank texture to something contained in our sprite sheet, we can place _terrain inside _gameBatchNode.

The same thing is done with the Block class, which now, in the final version of the game, behaves like another textureless...