In this video, the world is one continuous loop. Each set of colored blocks represent one “room” in the game world, which are pieced together to form a continuous scrolling world.
Tile Size Change
Scaled down the tiles from 64×64 to 48×48. This allows 15 rows (previously 11) and 26 columns (previously 20) on the 1280×720 pixel screen at once.
Scrolling isn’t too difficult, but it really makes you think. First, set two constants which will be your left and right bounds. If the player walks right and their position is greater than the right bounds, then don’t move the player and scroll the level left. This can be accomplished by storing an X offset variable. Then, draw all the tiles using the X offset to shift the screen. I ended up setting these at 200 for the left bound and 1080 for the right bound, which gives 200 pixels of buffer on both sides of the screen.
Once the offset equals the size of the room minus the right bounds, then it means the player should be moved to the next room. I created a Level class which keeps track of all of the level’s rooms. Additionally, each room has a reference to the left and right room. When moving right to the next room, set the current room to the room to the right, and set the X offset to room size minus the right bounds. Be careful as well to only check for a right room flip whenever the player is at the right bounds, or a left room flip when the player is at the left bounds. Otherwise, the player will continually flip rooms, because the offset will be set to a value outside of the bounds at the other end. I’ll admit, this gave me a bit of a headache getting all of this straight. However, in the end this will work out much better than having one huge array. I had to draw out the transitions on paper first to get it straight in my head.
What made this more of a pain was the fact that my screen width (1280) isn’t a multiple of the tile size (48). Thefore, I only used 26 columns for a room, which left a small difference (32 pixels) between the room size and the screen size. Remembering when to use the screen size and when to use the room size was quite cumbersome, but in the long run I think this will allow rooms to be created of any size.
Setting the last room’s right room to the first room, and setting the first room’s left room to the last room turns it into a continuous scroller, similar to games like Magic Sword or Odin Sphere. I’m a big fan of those games, so I’m going to leave it that way for now.