Determine how to score levels

[alicerunsonfedora]

Currently, there is no implementation of how a score is calculated for a level. This can be problematic since Game Center achievements and leaderboards may require a better system, and the AI agents will definitely need it. A scoring system should be in place to help facilitate this.

Notes to keep in mind:

• The current codebase doesn't allow direct movement (i.e., "move in x direction"); rather, it uses a physics based system where the sprite is given an impulse force and moves.
• There may be different ways to score a level, including times, efficient paths, costume usage, etc.
• Game Center challenges, achievements, and levels may not necessarily need to use the same scoring system as the agents do.

[alicerunsonfedora]

I propose that there are multiple scores that can be calculated for a given level:

• The self-status scores are a collected set of scores that track information such as time to completion and costume usage scores. These scores can be used for Game Center achievements where players can submit scores to Game Center leaderboards and achievements.
• The game state scores are a collected set of scores that will track the state of the game on multiple levels. These scores are used specifically for AI agents. These can include the following:
  • Position away from a particular item. Due to the current implementation of movement, telling the agent to just "move left" isn't enough. Position detection should be relative to the matrix data when initializing from the tile map, where the agent should move in a particular direction until the player is within the range of the target.
  • Number of unactivated inputs that link to the exit.
  • Living cost (time).