GamePlay Design Document

Created by: Julia Tartakovsky

• Introduction:

  This document describes the design of our game, elF-Zero Winter Break. Our game is a remake of the 8-bit Nintendo ExciteBike Game. The game platform is Electro and the game utilizes the physics engine.

 

• Goal of the Game:

• To reach the track's finish line in the fastest time possible.
• Have a FUN time playing!!!

• Features of the Game:

  We have multiple  AI’s, a finely tuned physics engine to maximize the FUN factor of the game, interesting obstacles and a complex terrain, a complete menu system that includes a start, controls, top 5 (high score) and exit screen, a detailed model of the snowmobile, complete game sound effects that feature multiple sounds per event, collidable objects and powerups, a concise heads up display that features an overheating bar, a speedometer and the game time, also we use varying camera angles as in the case when a boost is triggered and a dramatic camera angle including a shake effect is initiated.

• Artificial Intelligence:
  
  
  • Our game's AI is decision point driven. The game track is divided into multiple decision points where the AI randomly selects from a number of paths to follow. Of these paths, there are paths that are more adavantageous than others. Also, there are multiple waypoints per path so that the path can be more complex than just a straight line.
    
    
  • There are three groups of waypoints: The first group of waypoints is the most advantageous because it causes the AI to avoid the most difficult obstacles, drive over/through candy-cane boosts and cool off wreaths. The second group of waypoints is of medium advantage because it causes the AI to drive over the most difficult obstacles half of the time and the other half of the time it drives over candy-cane boosts and cool off wreaths. Lastly, the third group of waypoints is least advantageous since it causes the AI 3 out of 4 times to avoid candy-cane boosts and cool off wreaths and drive over the most difficult obstacles.
    
    
  • The game AI consists of three personalities. The first personality is labeled Mad because the AI enters the aggressive state when it is within 15 units from the player and returns to the passive state when it is 2 units behind the player (by that time the AI would have already rammed the player due to momentum). Mad AI will go into the aggressive state 90% of the time when it is within the proper distance. The second AI personality is labeled Angry because it enters the aggressive state when it is within 10 units from player and Angry AI returns to the passive state when it is 3 units behind the player (by that time the AI would have already rammed the player due to momentum). Angry AI goes into an aggressive state 70% of the time within the previously discussed distance. Finally, the last AI personality is labeled the Shy personality because it never goes into the aggressive state, it exclusively follows its randomly chosen waypoint groups and it is in the high speed mode 50% of the time.
    

 

• Finely Tuned Physics Engine:
  

The focus was on the FUN and ease of playablility, over an "accurate simulation". The game has dynamic collisions throughout the game between terrain, snowmobiles and obstacles. Well coordinated jumps and high rate of successful landings.

 

• Complete Menu System:
  
  
  • The game has a main menu with animated submenus. The main menu features an option to play the game, get help for learning the controls of the game (it's on a seperate screen), see the top five high scores (also a seperate screen), and the exit option to leave the main menu.
    
    
  • The top five high scores menu is displayed in one of three cases: after a player who has a top score enters his/her initials, after a non-high score player completes the game, and when the top five menu is selected from the main menu.
    
    • The existing high scores displayed are read in from a file and the new scores are written to the file.
      
      
  • Important element of the game that makes the player want to keep playing the game and also have their friends compete with them -- that's what we ended up doing in our group!
    

   

• Detailed Snowmobile Models:
  
  

The person on the snowmobile moves up when the snowmobile is in the air and sits down when the snowmobile is on the ground. The person on the snowmobile is oufitted in the Christmas theme gear topped off with a Santa hat. The persons on the snowmobiles have different colored shirts and the models were detailed to such a point that they would be loaded without issues and still look good.

 

• Complete Game Sound Effects:
  

• The game features complete game sound effects where there are multiple sound effects per event. The decision to have multiple sound effects stemmed from the fact that having the same sounds play over and over would be monotonous. In real life, seemingly same events produce varying sounds and this was carried out in our game.
  
  
• The sounds are event driven and here is a brief listing of the game sounds:
  • Hitting against the rail
  • Various Landing Sounds where the exact sound is randomly selected
  • Numerous collision sounds
  • Cool Off & boost picked up sounds
  • Overheat alarm sound
  • Ready, Set, Go noise
  • Wipeout Sound
  • Lap Sound
  • Engine Sounds (frequency adjusted to match RPM)
  • Wind sounds when the player reached a high elevation such as when the player is in the air while executing a jump
  • Rail sound
    

 

• Varying Camera Angles :
  
  
  • During a boost, we have a short dramatic camera angle where the camera zooms in with a forward-like view with a screen shaking affect (after a candy-cane is picked up).
  • The default game camera angle provides the player with a side scrolling view.

 

• How Visual Effects Were Implemented :
  
  
  • The falling snow effect throughout the game helped maintain the winter break theme of of the game and also looked pleasing to the eye. The falling snow was implemented using a vertex program to modify the behavior of the Electro Galaxy Implementation.
  • The shadows in the game where sprites overlayed below the snow mobile. Before this approach was implemented, first we attempted to modulate the ground texture with a shadow texture but we chose to not use it because it was not the best solution in Electro.
  • Reflections in the game utilized Electro's Environment Maps.
    

   

• Finite State Machines:





 





 

• Design Tradeoffs Made :
  
  

Originally we were going to have two-wheel bikes in the game in order to stay close to the original ExciteBike game. After testing the game out with a two-wheel bike, we quickly came to the conclusion that such a vehicle is extremely unstable. Following that, we went on to try a a two-wheeler in appearance that in reality is a four-wheeler with two invisible wheels. And this also was not a vehicle we wanted to move forward with because it did not portray the control and feel of the vehicle we wanted. Next, we decided to go with the ATV as our game vehicle. There were two problems with the ATV game. First, the vehicle was still pretty unstable and just not really all that fun to play. Secondly, the game looked BORING with a dirt road, green grass and just no "coolness" element to it. We looked more and more into the game idea thus far and saw that the best future for the games lies in something more edgy, appealing to the eye, easy to control, and FUN! And from this thinking, our game was born.