Wednesday, October 28, 2015

Science Fact or Cinematic Fiction?

Video games have recently become one of the biggest forms of entertainment. Games involving running, jumping, fighting, racing, shooting, anything, all try to achieve a common goal: fun for the player. However, in that quest to entertain the player, many video games often break the rules of physics. Some games do this because of hardware limitations at the time, some do it for humor, and some do it as intentional design in gameplay. In this paper we’ll be looking at three games that are all considered good, yet all break the laws of physics. We’ll be focusing on the action/reaction principle, which states that every action force must be met with an equal and opposite reaction force.
The first game is Super Mario Bros. (1985) for the NES. This game is 2D platformer about a plumber traversing numerous levels in order to find the Mushroom Kingdom's princess.There are 2 main mechanics in this game: running and jumping. The player runs by holding down the B button, and jumps by holding down the A button. The longer the player holds down A, the higher Mario jumps.This means that, when standing still and upright, Mario's jump can reach a variety of heights. He can achieve a short hop and a high jump from the same standing position.
This opposes the law of action and reaction, as the action (Mario applying force to the ground) and the reaction (the ground applying force on Mario, pushing him into the air) don't have a consistent relationship. If this game were more realistic, Mario would have to crouch first before he could jump high. Crouching would allow Mario to have more time in contact with the ground, which allows for more force to be applied on the ground over a greater period of time, which then leads to a greater jump height.
In fact, crouching is already a feature in Super Mario Bros., but it's more for ducking under attacks and has no effect on the height of the jump. (It should be noted that this particular game is Super Mario Bros. 1 for the NES, other Mario games have slightly different mechanics for crouching.)
The second game is Super Smash Brothers (1999-2014), which is fighting game series that takes characters from all over the Nintendo universe and throws them into one arena. Players hit each other to rack up "damage percentage" on their opponents. The higher the percentage, the easier it is to knock an opponent off stage.
In this game, when the player hits an opponent, there is no reaction on the player. The player could send their opponent flying off the stage with one good punch, but they would not go flying off the stage in the opposite direction. This because the force of the attack is tied to the damage percentage. Increasing the percentage of a player effectively lowers their mass.
This is testable. We can exclude any variables by choosing the same character for both players and having their percentages both at 0. We can also reduce friction by choosing a stage with icy floors or having the characters hit each other in the air. When Player A kicks Player B midair, B gets sent flying while A remains in the same horizontal position.
This violates the law of action/reaction because the action (applying force on an opponent) is not met with a reaction (having force applied back on the player). To make this more realistic, players attacking should also be pushed back with an appropriate force, and that force should be consistent with the strength of the attack, the mass of the opponent, the mass modifier that is damage percentage, and any force the player is exerting on the ground.
The third and final game is Lethal League (2014), in which you play a high-speed, high-octane game of what's essentially fighting-game handball. Players knock a baseball around a 2D stage, and that ball can ricochet off walls as players attempt to knock each other out with it. If an opponent is hit by the ball, they're out for the round. The ball increases in velocity with each consecutive hit, and can reach lightning speeds. If a player hits the ball when it has a high velocity, the ball will pause for a moment before zipping around the stage.
This breaks the law of action/reaction in a different way than previous examples. In standard physics, when an action force is applied, the reaction force is immediate. In this game, however, the reaction force has a noticeable delay. When a player hits the ball, there is a pause before either the player or the ball move. This is not a slow motion effect either, as other players can still move around in real-time. To make this more realistic, all forces must be applied simultaneously.
The law of action/reaction is also broken by the fact that the player character, which can only exert so much strength, can hit a ball and have it travel at near-lightning speeds. The ball is not light, either, as it can knock out opponents at even the slowest of speeds. Additionally, the player receives no recoil. The action force (the player hitting the ball hard enough to reach high speeds) doesn’t have a matching reaction force (the ball hitting the player back). So to make this more realistic, the player would need to experience some kind of visible recoil when hitting the ball, especially when it’s traveling at high speeds.
Video games tend to disobey the laws of physics a lot, but sometimes for good reason. While all three of these games hardly follow realistic physics, they’re still fun and enjoyable. For these particular games, the changes in physics seem very intentional. As two of them are fighting games, it makes sense that recoil is ignored as it would just make the game feel clunky. And all the games expect the player to react quickly, so they sacrifice realism for responsiveness. These games work because, while not physically accurate, they behave the way the player expects them to. It’s only when games start to go against that expectation that suspension of disbelief is broken, and the player is pulled out of the experience.

Wednesday, October 21, 2015

Outline - Action-Reaction in Video Games

  1. Intro
    1. action-reaction and video games
  2. Body
    1. Super Mario Bros
      1. jumping high without crouching
      2. crouch function independent of jump function
      3. contrast with shadow of the colossus
    2. Super Smash Bros
      1. reaction force missing when doing a smash attack
      2. test using two exact same characters
      3. in fact, acceleration of action force is based on damage percent instead of weight
    3. Lethal League
      1. in this game, the action-reaction principle is not immediate
      2. the harder you hit the ball, the longer the delay before it starts moving
      3. also there is no recoil when you hit the ball hard
  3. Conclusion
    1. changing rules of physics for game feel/design

Wednesday, October 7, 2015

Stop Motion Animation of Falling


I shot this using my phone and the Stop Motion Studio app. I put my phone on the edge of my desk so that it overhung the floor. I planned out the arcs using Fourth Down at Half Time. For the X-axis, I measured the distance from the peak of the arc to the contact and multiplied that by 3/4 to get the halfway point. I then took the distance between that point and each of the keys and multiplied those by 3/4 to get the inbetweens. For the Y-axis, I simply spaced it out to move 2 inches every frame.