Why don't you just make it a sprite that moves like a bag like Joeb said?? Like a background picture? (This is sorta what Joeb said)

My guess is that the background tiles are not C objects. I think the tile layers are simple arrays that refer to visual object IDs in a grid layout (apologies if I'm not using the right terminology). It would take a total restructure of the layer system to make any tile move in an increment that wasn't exactly equal to the width of a tile.

EDIT: Oh, wait. You're not talking about tiles. Nemmine.

One big problem I can think of, now that I've caught myself up with the conversation, is that Jack and the other creatures aren't currently programmed to check for horizontal collisions with any sprites. They only react to horizontal collisions with tiles. They check for vertical collisions with moving platforms (some of them), but they would need a whole new set of routines to deal with the walls of, say, an elevator.

Joe, it's a lot more complicated than you may think. The original poster requested being able to "build onto" platforms. This would imply not just one brick, but perhaps a whole wall of bricks, each on top of the other, riding on the moving platform. Problems:

1) Tiles don't move. So I'd have to add new "wall tile" sprites, of every conceivable graphic, as a sprite, and program all monsters / Jack / etc. to treat them as normal walls.

2) The "building on top" of each other element would be very hard. When the platform moves, the brick riding on it would have to detect that it's on a moving platform, and therefore offset itself accordingly. BUT -- so does the brick "on top" of this brick! And so on.

There are plenty of other potential problems. For instance, a moving platform should turn around if the bricks "built onto" it hit a wall, even if the platform itself hit nothing. That would be really hard!

And from experience, I know that there are probably other problems I haven't even considered that I would discover once I tried to implement somethign like this.

BTW, the game is done in straight C, not C++, so there are no objects. I wish it were in C++... that would've made a lot of things easier. But I didn't learn object-oriented programming until I was nearly finished with the game.