PROGRAMMING LINX LEARNING GAME Linx Overview Linxis a game based on removing colored balls from a moving path by creating chains of three or more of the same color. Players control a firing mechanism (in the case of our game the firing mechanism is a fixed location on the screen); the mechanism can rotate 360 degrees and fire balls in any direction on the screen. This design document begins with the most basic implementation and incrementally adds complexity. Requirements for the most basic version of Linx: 1. Each play screen is composed of a unique curving path, where a fixed length string of colored balls enters the screen from end of the path and slowly rolls to the other end of the path. Total number of balls is flexible, generally ~100 on early screens (total number in more challenging levels). The level is completed when the player has either removed all balls from the moving path (win condition) or when the lead ball on the moving path makes contact with the terminating end of the path (loser condition). 2. A firing mechanism located in a fixed position on the screen with 360 degree rotation that shoots individual colored balls. When a ball shot by the player comes in contact with the moving string of balls on the path it s either inserted into the chain or removes balls from the chain depending on a number of conditions described later in this document. If the fired ball doesn t come in contact with the moving string of balls it simply flies off the screen (the game field does not have a bounding box other than objects specifically placed by the player (objects described later in this document). Figures 1 & 2 below display the most basic gameplay elements:
Figure 1: the most basic playable version of Linx contains a path with a home point where balls enter the screen and a terminating point where the game ends if any of the balls reach it. Balls proceed along the path at a fixed rate. The player rotates a firing mechanism that launches balls into the path if a launched ball enters the path and creates a string of at least three matching colors, all of the matching balls in that newly created string are removed. If the launched ball doesn t create a string of at least 3 matching colors, the launched ball becomes part of the main string.
Figure 2: In this image the player is aiming the firing mechanism at the point on the path shown by the green arrow. Players see the currently active ball loaded into the firing mechanism (orange in this case) and the next ball in line to be fired players can switch positions between the currently loaded ball and the next ball by clicking the right mouse button. There are a number of gameplay conventions consistent in each level: 1. At the start of the level, colored balls are shown entering the screen from the home location before the firing mechanism becomes active. Approximately 20 balls enter the play field before the firing mechanism becomes active (the firing mechanism becomes active by displaying a currently loaded ball and a next ball as shown in figure 1. Prior to becoming active players can rotate the firing mechanism but will have no balls to shoot. 2. The balls roll along the path at a fixed rate (unless a power up or power down has altered the speed described later in this document). 3. The playfield does not contain a bounding box balls the don t come in contact with the string of colored balls simply fly off screen (this is a component of player strategy) 4. Players can rotate the firing mechanism 360 degrees, and are able to see both the currently loaded ball and the ball that is next in line right clicking the mouse button swaps the currently loaded ball with the next ball. 5. When a fired ball encounters the string, one of two behaviors occurs: a. If the ball enters the string at a point where it does not create a group of at least three matching colors, the ball is inserted into the string at that point.
b. If the ball enters the string at a point where it creates a group of three or more matching colors, all of those same colored balls are removed from the string. When balls are removed from the string and the string is thus separated into two sections, one of two behaviors occurs (as shown in figures 2 & 3 below): i. If the balls on each end of the two new string sections that are closest to each other match, the string section closest to the terminating icon will magnetize to the string section closest to the home icon and reverse until the two meet ii. If the balls on each end of the two new string sections that are closest to each other don t match, the string section closest to the terminating icon will remain stationary until the main string section catches up when the two sections meet they will join to once again form a single string. Figure 3: in this image the player created a string of at least three matching colors on the last turn and made a gap in the main path; because the two balls on either side of the gap don t match, the section of the string closest to the terminating end of the path remains stationary until the main string catches up. Once the gap is closed the string proceeds along the path normally.
Figure 4: in this image the player created a group of at least three matching colors on the last turn and made a gap in the main path; because the two balls on either side of the gap match, the section of the string closest to the terminating end of the path reverses its direction and magnetizes back to the main string. Power ups and Power downs When a player removes a chain of 4 or more of the same colored balls, a randomly selected power up or powerdown ball replaces the removed chain. Power up and power down balls are activated and removed from the string when a regular group of the same colored balls is immediately adjacent and removed they behave is if they are the same color as the balls immediately adjacent, although they do not count as part of the creation of a group of three. Figures 5 8 demonstrate the process for creating and removing these special balls:
Figure 5: The player is about to remove a string of 4 or more same colored balls (orange as shown in the figure) this triggers the creation of a special power up ball shown in figure 6.
Figure 6: After removal of the 4 or more same colored string, a power up or power down is randomly selected from a group of special balls and inserted in the string. Each special ball is uniquely identifiable (note: we ll need custom graphics for each power up so players know which balls correspond to which behaviors).
Figure 7: The power up/down balls are limited wild cards, as they are removed with any group immediately adjacent to their position. They do not contribute to the creation of match 3 strings themselves, however. In this figure the blue ball about to be fired will not create a chain of 3 will the power up, as the power up does not contribute to the creation of chains.
Figure 8: the power up/down in this figure will be removed along with the newly created group of three red balls per the rule that power ups are removed along with any immediately adjacent chain of same colored balls (but themselves do not contribute to the chain). Types of power ups and power downs: Power up: Bomb ball: explodes 2 balls on either side of where it enters the string Slow ball: slows the speed of advancement by half for 10 seconds Stop ball: stops advancement for 5 seconds Wildcard ball: matches the color of the ball on either side of where it enters the string this is the one power up/down ball that DOES contribute to the creation of a match three chain. Power down: Speedy ball: doubles the speed of the string for 3 seconds Invisiball: hides the color of the ball being launched until it s fired Randomball: changes the color of every other ball in the string to a random color