I have written code, which I think works, to basically scroll around a tile based world. Fascinating. My problem is on the game dev side. I''m trying to use my library to do a basic test and it''s not working. Here''s the idea behind how I scroll up and down: IF SCROLL_DOWN { get info on the tile locate at (x, y+tileHeight) also get info on tile at (x+tileWidth, y+tileHeight) //why? in case the player isn''t evenly positioned over //just one tile, in which case we need to check both to //see if you can walk downwards if both of these tiles are walkable { if we''re not at the edge of the screen, then increment our y coordinate. Otherwise, don''t increment Y, but scroll the world down. } ELSE IF SCROLL_UP { Same thing (decrement Y instead of incrementing though), except that it checks these tiles: (x, y-1) and (x+tileWidth, y-1) } It works fine if I haven''t scrolled yet After I''ve scrolled downwards, when I scroll back up, sometimes things are off, like the player will stop moving as if there''s a wall but there really isn''t one (not for a certain amount of pixels at least). Basically, what algorithm would you use (assuming you had a working function to get info on a tile at a particular pixel coordinate and could pan your world just fine)? Is mine correct (then that means my lib is screwed up), or is there a better way to do it? Thanks a ton, I appreciate it.