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Monday, January 26, 2009

Tetris (Game)

Tetris (Russian: Те́трис) is a puzzle video game originally designed and programmed by Alexey Pajitnov in the Soviet Union. It was released on June 6, 1984, while he was working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow. He derived its name from the Greek numerical prefix tetra- (all of the game's pieces, known as Tetrominoes, contain four segments) and tennis, Pajitnov's favorite sport.

The Tetris game is a popular use of tetrominoes, the four element special case of polyominoes. Polyominoes have been used in popular puzzles since at least 1907, and the name is given by the mathematician Solomon W. Golomb in 1953. However, even the enumeration of pentominoes is dated to antiquity.
The game (or one of its many variants) is available for nearly every video game console and computer operating system, as well as on devices such as graphing calculators, mobile phones, portable media players, PDAs, Network music players and even as an Easter egg on non-media products like oscilloscopes. It has even inspired Tetris serving dishes and been played on the sides of various buildings, with the record holder for the world's largest fully functional game of Tetris being an effort by Dutch students in 1995 that lit up all 15 floors of the Electrical Engineering department at Delft University of Technology.
While versions of Tetris were sold for a range of 1980s home computer platforms, it was the hugely successful handheld version for the Game Boy launched in 1989 that established the reputation of the game as one of the most popular ever. Electronic Gaming Monthly's 100th issue had Tetris in first place as "Greatest Game of All Time". In 2007, Tetris came in second place in IGN's "100 Greatest Video Games of All Time". It has sold more than 70 million copies. In January 2010, it was announced that Tetris has sold more than 100 million copies for cell phones alone since 2005.

Gameplay
The seven one-sided tetrominoes in their Tetris Worlds colors. Top row, left to right: I, J, L, O. Bottom row: S, T, Z.

A random sequence of tetrominoes (sometimes called "tetrads" in older versions)—shapes composed of four square blocks each—fall down the playing field (a rectangular vertical shaft, called the "well" or "matrix"). The objective of the game is to manipulate these tetrominoes, by moving each one sideways and rotating it by 90 degree units, with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and any block above the deleted line will fall. With every ten lines that are cleared, the game enters a new level. As the game progresses, each level causes the tetrominoes to fall faster, and the game ends when the stack of tetrominoes reaches the top of the playing field and no new tetrominoes are able to enter. In certain versions, the game can also end if the player is able to get all the way to level 15.
All of the tetrominoes are capable of single and double clears. I, J, and L are able to clear triples. Only the I tetromino has the capacity to clear four lines simultaneously, and this is referred to as a "tetris". (This may vary depending on the rotation and compensation rules of each specific Tetris implementation. For instance, in the Super Rotation System used in most recent implementations,[16] called "Easy Spin" in Tetris Worlds, certain rare situations allow T, S and Z to 'snap' into tight spots and clear triples.)

Scoring
The scoring formula for the majority of Tetris products is built on the idea that more difficult line clears should be awarded more points. For example, a single line clear in Tetris Zone is worth 100 points, while a back-to-back Tetris is worth 1,200.
Nearly all Tetris games allow the player to press a button to increase the speed of the current piece's descent, rather than waiting for it to fall. If the player can stop the increased speed before the piece reaches the floor by letting go of the button, this is a "soft drop"; otherwise, it is a "hard drop" (some games allow only soft drop or only hard drop; others have separate buttons). Many games award a number of points based on the height that the piece fell before locking.

Gravity
Traditional versions of Tetris move the stacks of blocks down by a distance exactly equal to the height of the cleared rows below them. Contrary to the laws of gravity, blocks may be left floating above gaps. Implementing a different algorithm that uses a flood fill to segment the playfield into connected regions will make each region fall individually, in parallel, until it touches the region at the bottom of the playfield. This opens up additional "chain-reaction" tactics involving blocks cascading to fill additional lines, which may be awarded as more valuable clears.

History
Screenshot of the 1986 IBM PC version

Tetris has been involved in many legal battles. In June 1984, Alexey Pajitnov created Tetris on an Elektronika 60 while working for the Soviet Academy of Sciences at their Computer Center in Moscow with Dmitry Pavlovsky, and Vadim Gerasimov ported it to the IBM PC. Gerasimov reports that Pajitnov chose the name "Tetris" as "a combination of 'tetramino' and 'tennis'." From there, the PC game exploded into popularity, and began spreading all around Moscow. The most recent version of this port is available on Gerasimov's web site.
The IBM PC version eventually made its way to Budapest, Hungary, where it was ported to various platforms and was "discovered" by a British software house named Andromeda. They attempted to contact Pajitnov to secure the rights for the PC version, but before the deal was firmly settled, they had already sold the rights to Spectrum HoloByte. After failing to settle the deal with Pajitnov, Andromeda attempted to license it from the Hungarian programmers instead.
Meanwhile, before any legal rights were settled, the Spectrum HoloByte IBM PC version of Tetris was released in the United States in 1986. The game's popularity was tremendous, and many players were instantly hooked—it was a software blockbuster, with reviews such as in Computer Gaming World calling the game "deceptively simple and insidiously addictive".
The details of the licensing issues were uncertain by this point, but in 1987 Andromeda managed to obtain copyright licensing for the IBM PC version and any other home computer system.
For Amiga and Atari ST two different versions by Spectrum HoloByte and Mirrorsoft became available. The Mirrorsoft version did not feature any background graphics while the Holobyte version had a background picture related to Russian themes for each level. Games were sold as budget titles due to the game's simplicity. Spectrum's Apple II package actually contained three diskettes with three different versions of the game, for the Apple II+ and Apple IIe on separate DOS 3.3 and ProDOS 5-1/4" diskettes, and for the Apple IIgs on a 3-1/2" diskette, none of which was copy-protected: the included documentation specifically charged the purchaser on his or her honor to not give away or copy the extra diskettes.
By 1988, the Soviet government began to market the rights to Tetris through an organization called Elektronorgtechnica, or "Elorg" for short. Pajitnov had granted his rights to the Soviet Government, via the Computer Center he worked at for ten years.[24] By this time Elorg had still seen no money from Andromeda, and yet Andromeda was licensing and sub-licensing rights that they themselves did not even have.

Monday, January 19, 2009

The Legend of Zelda (Game)

The Legend of Zelda​ (ゼルダの伝説 Zeruda no Densetsu?), occasionally called Legend of Zelda or Zelda, is a high fantasy action-adventure video game series created by Japanese game designers Shigeru Miyamoto and Takashi Tezuka. It was developed and published by Nintendo, with some portable installments outsourced to Flagship/Capcom and Vanpool. Considered one of Nintendo's most important franchises, its gameplay consists of a mixture of action, adventure, and puzzle solving. The series centers on Link, the playable main character and protagonist. Link is often given the task of rescuing Princess Zelda in the most common setting of the series, Hyrule, from Ganon—also known as Ganondorf—who is the primary antagonist of the series. However, other settings and antagonists have appeared throughout the games, with Vaati having recently become the series' secondary antagonist. The story commonly involves a relic known as the Triforce, which is a set of three golden triangles of omnipotence. Link holds the Triforce of Courage, Zelda holds the Triforce of Wisdom, and Ganon holds the Triforce of Power for various reasons between the different versions of the game. The protagonist in each game is usually not the same incarnation of Link, but a few exceptions do exist.

As of April 2010, The Legend of Zelda series has sold over 59 million copies since the release of the first game, The Legend of Zelda, and continues to be successful worldwide. The original Legend of Zelda is the fourth best selling NES game, of all time. The series consists of 15 official games on all of Nintendo's major consoles, as well as several spin-offs. An American animated series based on the games aired in 1989, and individual manga adaptations which are officially endorsed and commissioned by Nintendo have been produced in Japan since 1997.

Gameplay
The Legend of Zelda games feature a mixture of puzzles, action, adventure/battle gameplay, and exploration. These elements have remained constant throughout the series, but with refinements and additions featured in each new game. The player is frequently rewarded for solving puzzles or exploring areas. Most Zelda games involve locating and exploring dungeons, in which puzzles are solved and enemies fought, then defeating the dungeon's boss. Each dungeon usually has one major item inside, which is usually essential for solving many of the puzzles in that dungeon and often plays a crucial role in defeating that dungeon's boss. Some items are consistent and appear many times throughout the series, such as bombs, boomerangs, magic swords and shields, and bows and arrows, while others are unique to a single game. The series also consists of stealth gameplay, where the player must avoid enemies while proceeding through a level, as well as racing element.

Chronology
Though the chronology of the Legend of Zelda series is subject to much debate among fans, numerous materials and developer statements have partially established an official timeline of the released installments. Zelda II: The Adventure of Link is a direct sequel to the original The Legend of Zelda and takes place several years later. The third game, A Link to the Past, is a prequel to the first two titles and is followed by Link's Awakening. Ocarina of Time is also a prequel, taking the story many centuries back and implicitly telling the Imprisoning War from the manual of A Link to the Past. The ending of this game caused the timeline to split, with the child era leading into the direct sequel Majora's Mask, and Twilight Princess set more than 100 years later. The Wind Waker is parallel and takes place in the other timeline branch, more than a century after the adult era of Ocarina of Time. Phantom Hourglass is a continuation of Link's and Tetra's story, followed by Spirit Tracks about 100 years later. Skyward Sword will be a prequel again, taking place before Ocarina of Time. At the time of its release, Four Swords for the Game Boy Advance was considered the oldest tale in the series' chronology, with Four Swords Adventures set sometime after its events. The Minish Cap precedes the two games, telling the story of Vaati and the Four Sword's birth. There have been no statements about the placement of the Oracle titles, or about which timeline branch some of the earlier installments are meant to be set in.

Inspiration
The Legend of Zelda was principally inspired by Shigeru Miyamoto's explorations as a young boy in the hillsides surrounding his childhood home in Kyoto, Japan where he ventured into forests with secluded lakes, caves, and rural villages. According to Miyamoto, one of his most memorable experiences was the discovery of a cave entrance in the middle of the woods. After some hesitation, he apprehensively entered the cave, and explored its depths with the aid of a lantern. Miyamoto has referred to the creation of the Zelda games as an attempt to bring to life a "miniature garden" for players to play with in each game of the series.
Hearing of American novelist F. Scott Fitzgerald's wife Zelda, Miyamoto thought the name sounded "pleasant and significant". Paying tribute, he chose to name the princess after her, and titled his creation The Legend of Zelda.

History
According to the in-game backstories, long ago, three golden goddesses descended and created the land of Hyrule. Din, the Goddess of Power, with her powerful, flaming arms, cultivated the empty space, and created the red earth. Nayru, the Goddess of Wisdom, bestowed her divine Wisdom upon the land, and created the world's laws to give a sense of justice and order to the world, and to guide the people in the goddesses' absence. Farore, the Goddess of Courage, endowed Hyrule with her powers, creating life to follow this justice.

After their work was completed, the goddesses left a sacred artifact called the Triforce, which could grant the wishes of the user. It consisted of three golden triangles (each also called a "Triforce"—one of Wisdom, one of Power and one of Courage). However, because the Triforce was not divine, and could not judge between good and evil, the goddesses placed the Triforce in an alternate world called the "Sacred Realm" or the "Golden Land", hoping that a worthy person would one day seek it.
According to legend, the discoverer of the Triforce will receive the Triforce as a whole – along with the true force to govern all – only if that person has a balance of power, wisdom and courage. If the heart of that person is pure, the Sacred Realm will become a paradise. If the heart of that person is evil, the Sacred Realm will become a nightmarish world of evil. If they are unbalanced, they will only receive the part of the Triforce that represents the characteristic they most demonstrate, with the remaining parts of the whole transferring into the people in Hyrule who most exemplify the other two traits. The Triforce was first distributed as such starting in Ocarina of Time, with the Triforces of Power, Wisdom, and Courage being transferred to Ganondorf, Princess Zelda, and Link, respectively. While the Triforce of Power and Wisdom have been part of the series since the original The Legend of Zelda, it was only in The Adventure of Link that the Triforce of Courage was first introduced, being obtained by Link at the end of his quest. The triforce, or even a piece of it, is not always distributed as a whole. Such as in Wind Waker, Link must find all the pieces (called Triforce Shards) of the Triforce of Courage before he can return to Hyrule.
The fictional universe established by the Zelda games sets the stage for each adventure. Many games take place in lands with their own back-stories. Termina, for example, is a parallel world while Koholint is an island far away from Hyrule that appears to be part of a dream.

Saturday, January 17, 2009

Swarm Intelligence

Swarm intelligence (SI) is the collective behaviour of decentralized, self-organized systems, natural or artificial. The concept is employed in work on artificial intelligence. The expression was introduced by Gerardo Beni and Jing Wang in 1989, in the context of cellular robotic systems.
SI systems are typically made up of a population of simple agents or boids interacting locally with one another and with their environment. The agents follow very simple rules, and although there is no centralized control structure dictating how individual agents should behave, local, and to a certain degree random, interactions between such agents lead to the emergence of "intelligent" global behavior, unknown to the individual agents. Natural examples of SI include ant colonies, bird flocking, animal herding, bacterial growth, and fish schooling.
The application of swarm principles to robots is called swarm robotics, while 'swarm intelligence' refers to the more general set of algorithms. 'Swarm prediction' has been used in the context of forecasting problems.

Example Algorithms

Ant colony optimization
Ant colony optimization (ACO) is a class of optimization algorithms modeled on the actions of an ant colony. ACO methods are useful in problems that need to find paths to goals. Artificial 'ants'—simulation agents—locate optimal solutions by moving through a parameter space representing all possible solutions. Real ants lay down pheromones directing each other to resources while exploring their environment. The simulated 'ants' similarly record their positions and the quality of their solutions, so that in later simulation iterations more ants locate better solutions. One variation on this approach is the bees algorithm, which is more analogous to the foraging patterns of the honey bee.

River formation dynamics
River formation dynamics (RFD) is an heuristic method similar to ant colony optimization (ACO). In fact, RFD can be seen as a gradient version of ACO, based on copying how water forms rivers by eroding the ground and depositing sediments. As water transforms the environment, altitudes of places are dynamically modified, and decreasing gradients are constructed. The gradients are followed by subsequent drops to create new gradients, reinforcing the best ones. By doing so, good solutions are given in the form of decreasing altitudes. This method has been applied to solve different NP-complete problems (for example, the problems of finding a minimum distances tree and finding a minimum spanning tree in a variable-cost graph). The gradient orientation of RFD makes it specially suitable for solving these problems and provides a good tradeoff between finding good results and not spending much computational time. In fact, RFD fits particularly well for problems consisting in forming a kind of covering tree.

Particle swarm optimization
Particle swarm optimization (PSO) is a global optimization algorithm for dealing with problems in which a best solution can be represented as a point or surface in an n-dimensional space. Hypotheses are plotted in this space and seeded with an initial velocity, as well as a communication channel between the particles. Particles then move through the solution space, and are evaluated according to some fitness criterion after each timestep. Over time, particles are accelerated towards those particles within their communication grouping which have better fitness values. The main advantage of such an approach over other global minimization strategies such as simulated annealing is that the large number of members that make up the particle swarm make the technique impressively resilient to the problem of local minima.

Stochastic diffusion search
Stochastic diffusion search (SDS) is an agent-based probabilistic global search and optimization technique best suited to problems where the objective function can be decomposed into multiple independent partial-functions. Each agent maintains a hypothesis which is iteratively tested by evaluating a randomly selected partial objective function parameterised by the agent's current hypothesis. In the standard version of SDS such partial function evaluations are binary, resulting in each agent becoming active or inactive. Information on hypotheses is diffused across the population via inter-agent communication. Unlike the stigmergic communication used in ACO, in SDS agents communicate hypotheses via a one-to-one communication strategy analogous to the tandem running procedure observed in some species of ant. A positive feedback mechanism ensures that, over time, a population of agents stabilise around the global-best solution. SDS is both an efficient and robust search and optimisation algorithm, which has been extensively mathematically described.

Gravitational search algorithm
Gravitational search algorithm (GSA) is constructed based on the law of Gravity and the notion of mass interactions. The GSA algorithm uses the theory of Newtonian physics and its searcher agents are the collection of masses. In GSA, we have an isolated system of masses. Using the gravitational force, every mass in the system can see the situation of other masses. The gravitational force is therefore a way of transferring information between different masses.(Rashedi et.al, 2009)

Intelligent Water Drops
Intelligent Water Drops algorithm (IWD) is a swarm-based nature-inspired optimization algorithm, which has been inspired from natural rivers and how they find almost optimal paths to their destination.These near optimal or optimal paths follow from actions and reactions occurring among the water drops and the water drops with their riverbeds. In the IWD algorithm, several artificial water drops cooperate to change their environment in such a way that the optimal path is revealed as the one with the lowest soil on its links. The solutions are incrementally constructed by the IWD algorithm. Consequently, the IWD algorithm is generally a constructive population-based optimization algorithm.

Charged System Search
Charged System Search (CSS) is a new optimization algorithm based on some principles from physics and mechanics. CSS utilizes the governing laws of Coulomb and Gauss from electrostatics and the Newtonian laws of mechanics. CSS is a multi-agent approach in which each agent is a Charged Particle (CP). CPs can affect each other based on their fitness values and their separation distances. The quantity of the resultant force is determined by using the electrostatics laws and the quality of the movement is determined using Newtonian mechanics laws. CSS is applicable to all optimization fields; especially it is suitable for non-smooth or non-convex domains. This algorithm provides a good balance between the exploration and the exploitation paradigms of the algorithm which can considerably improve the efficiency of the algorithm and therefore the CSS also can be considered as a good global and local optimizer simultaneously.

Sunday, January 11, 2009

Game Controller

A game controller is a device used with games or entertainment system used to control a playable character or object, or otherwise provide input in a computer game. A controller is typically connected to a game console or computer by means of a wire, cord or nowadays, by means of wireless connection. Controllers which have been classified as games controllers are keyboards, mice, game pads, joysticks, etc. Special purpose devices, such as steering wheels for driving games and light guns for shooting games, are also game controllers. Devices such as mice and keyboards can be emulated with a game pad through the use of programs such as 'JoyToKey'.
The main function of a game controller is to govern the movement/actions of a playable body/object or otherwise influence the events in a video or computer game. The type of controller used in a game depends on the genre of the game being played (i.e. Steering Wheel controllers for driving games, yoke like for flying, etc).

Types of Game Controllers

Gamepad
A gamepad, also known as a joypad, is the most common kind of game controller, held in both hands with thumbs and fingers used to provide input. Gamepads can have anywhere from two buttons to a dozen or more, combined with multiple omnidirectional analogue or digital control sticks. Gamepads generally feature a set of action buttons handled with the right fingers or thumb, and a direction controller handled with the left. These let the player control the game element movements in up to three dimensions[citation needed], with many buttons to perform quick actions. Due to the ease of use and precision of gamepads, they have spread from traditional consoles where they originated to computers as a common input device.
Most modern game controllers are a variation of a standard gamepad. Some common additions to the standard pad include shoulder buttons placed along the edges of the pad, centrally placed buttons labeled start, select, and mode, and an internal motor to provide haptic feedback.
Gamepads are the primary means of input on nearly all modern video game consoles. Gamepads are also available for personal computers, but not all computer games support gamepads, preferring the more conventional keyboards and mice. However, most console emulators support gamepads.

Paddle
A paddle is a controller that features a round wheel and one or more fire buttons. The wheel is used to typically control movement of the player or an object along one axis of the video screen. Paddle controllers were the first analog controllers; they died out when "paddle and ball" type games fell out of favor. A variation on the Paddle, the Atari driving controller appeared on the Atari 2600. Designed specifically for the game Indy 500, It was almost identical in operation and design to the regular paddle controller. However, its wheel can be continuously rotated in either direction, and it was missing the extra paddle included on the previous model. Unlike a spinner, friction prevented the wheel from gaining momentum.

Trackball
A trackball is basically an upside-down mouse that is manipulated with the palm of one's hand. It has the advantage of not requiring a lot of desktop space, and that it is as fast as one can roll the ball on it. This is faster than one can move a mouse due to space not being an issue.
Notable uses of a Trackball as a gaming controller would be games such as Centipede, Marble Madness, Golden Tee and Sonic Arcade.

Joystick
This joystick is a peripheral that consists of a handheld stick that can be tilted around either of two axes and (sometimes) twisted around a third. The joystick is often used for flight simulators. HOTAS controllers, composed of a joystick and throttle quadrant (see below) are a popular combination for flight simulation among its most fanatic devotees. Most joysticks are designed to be operated with the user's primary hand (e.g. with the right hand of a right-handed person), with the base either held in the opposite hand or mounted on a desk.

Arcade style Joystick
This device can also be a home version of the kind used in the arcade, or for use on emulators. It features a shaft that has a ball or drop-shaped handle, and one or more buttons for in game actions. Generally the layout has the joystick on the left, and the buttons on the right, although there are instances when this is reversed.

Throttle quadrant
A throttle quadrant, as the name indicates, is a set of one or more levers that are most often used to simulate throttles or other similar controls in a real vehicle, particularly an aircraft. Throttle quadrants are most popular in conjunction with joysticks or yokes used in flight simulation.

Steering wheel
The steering wheel, essentially a larger version of a paddle, is used for racing simulators such as Live for Speed, Grand Prix Legends, GTR2, and Richard Burns Rally. The first steering wheels appeared in the Nintendo 64 and PlayStation era[citation needed]. Many are force feedback (see Force Feedback Wheel), designed to give the same feedback as would be experienced when driving a real car, but the realism of this depends on the game. They usually come with pedals to control the gas and brake. Shifting is taken care of with in various different ways including paddle shifting systems, simple stick shifters which are moved forward or back to change gears or more complex shifters which mimic those of real vehicles, which may also use a clutch. Most wheels turn only 200 to 270 degrees lock-to-lock but some models, such as the Logitech Driving Force Pro, Logitech G25 and Logitech G27 can turn 900 degrees, or 2.5 turns, lock-to-lock.
The Namco Jogcon paddle was available for the PlayStation game R4: Ridge Racer Type 4. Unlike "real" video game steering wheels, the Jogcon was designed to fit in the player's hand. Its much smaller wheel (diameter roughly similar to a soda can's) resembles the jog-and-shuttle control wheel used on some VCRs.
The game Mario Kart Wii is bundled with the Wii Wheel, a steering wheel-shaped shell that the Wii Remote is placed inside thus using the Wii Remote's motion sensing capabilities to control the game.

Yoke
A yoke is very similar to a steering wheel except that it resembles the control yoke found on many aircraft and has two axes of movement: not only rotational movement about the shaft of the yoke, but also a forward-and-backward axis equivalent to that of pitch control on the yoke of an aircraft. Some yokes have additional controls attached directly to the yoke for simulation of aircraft functions such as radio push-to-talk buttons. Yokes, like throttle quadrants and pedals, are popular with serious flight-simulation enthusiasts.

Pedals
Pedals may be used for driving simulations or flight simulations. In the former case, an asymmetric set of pedals can simulate accelerator, brake, and clutch pedals in a real automobile. In the latter case, a symmetric set of pedals simulates rudder controls and toe brakes in an aircraft. As mentioned, most steering wheel controllers come with a set of pedals.

Keyboard and mouse
The keyboard and mouse are typical input devices for a personal computer and are currently the main game controllers for computer games. The mouse is often used with a mousepad to achieve greater speed, comfort and accuracy for the gamer. Some video game consoles also have the ability to function with a keyboard and a mouse. The computer keyboard is modeled after the typewriter keyboard and was designed for the input of written text. A mouse is a handheld pointing device used in addition to the keyboard. For games, the keyboard typically controls movement of the character while the mouse is used to control the game camera or used for aiming.
While originally designed for general computer input, there are several keyboard and mouse peripherals available which are designed specifically for gaming, often with gaming-specific functions built-in. Examples include (but are not limited to) peripherals by Razer, the "Zboard" range of keyboards and Logitech's 'G' series.
The numeric keypad found on the keyboard is also used as a game controller and can be found on a number of separate devices, most notably early consoles, usually attached to a joystick or a paddle. The keypad is a small grid of keys with at least the digits 0-9.

Gaming keypads and programmable PC controllers
There are a few specialized controllers that are specifically used for FPSs, RTSs and some arcade type games. These controllers can be programmed to allow the emulation of keys, and macros in some cases. These generally resemble a small part of a keyboard but may also feature other inputs such as analog sticks. They were developed because some of these games require a keyboard to play, and some players find this to be awkward for such a task.

Touch screen
A touch screen is an input device that allows the user to interact with the computer by touching the display screen. It was first used on a dedicated console with the Tiger game.com. Nintendo popularized it for use in video games with the Nintendo DS; other systems including the Tapwave Zodiac as well as the vast majority of PDAs have also included this feature.
Modern touch screens use a thin, durable, transparent plastic sheet overlayed onto the glass screen. The location of a touch is calculated from the capacitance for the X and Y axes, which varies based upon where the sheet is touched.

Motion sensing
Nintendo's Wii system utilizes a new kind of controller, called the Wii Remote. It uses accelerometers to detect its approximate orientation and acceleration and an image sensor so it can be used as a pointing device. The Sixaxis, DualShock 3, and Move controllers for Sony's PlayStation 3 system have similar motion sensing capabilities.

Light gun
A light gun is a peripheral used to "shoot" targets on a screen. They usually roughly resemble firearms or ray guns. Their use is normally limited to rail shooter or shooting gallery games like those that came with the "Shooting Gallery" light gun. The first home console light gun was released on the Magnavox Odyssey; later on, Nintendo would include one standard on their Famicom and NES. Nintendo has also released a "shell" in the style of a light gun for the Wii Remote called the Wii Zapper which comes bundled with Link's Crossbow Training.


Others
Pinball controllers and multi-button consoles for strategy games were released in the past, but their popularity was limited to hardcore fans of the genre.
Dance pads, essentially a grid of flat pressure sensitive gamepad buttons set on a mat meant to be stepped on, have seen niche success with the popularity of rhythm games like Dance Dance Revolution and Pump it Up. The dance pad was first introduced on the Atari 2600, called the "Exus Foot Craz" pad. Nintendo later purchased the technology from Bandai and used it on their "Power Pad", for the Famicom and NES.
Balance board: The Wii Balance Board comes with the game Wii Fit. Several other game are in development which will be compatible with the balance board. This was preceded by decades by the Joyboard, made to plug into an Atari 2600, to play skiing and surfing games.
Rhythm games with controllers resembling musical instruments like guitars (GuitarFreaks, the Guitar Hero series, Rock Band and Rock Band 2), drums (Donkey Konga, DrumMania, Guitar Hero World Tour and the two Rock Band games), or maracas (Samba de Amigo) have also seen some success in arcades and home consoles. Another rhythm game based around the art of Djing and turntablism (DJ Hero) uses a turntable shaped peripheral.
Buzzers: A recent example of specialized, while very simple, game controllers, is the four large "buzzers" (round buttons) supplied with the PlayStation 2 & PlayStation 3 quiz show game series Buzz! (2005–present); both game and controllers clearly being inspired by the television show genre.
NeGcon: is a unique controller for racing games on the PlayStation. Physically it resembles a gamepad, but its left and right halves twist relative to each other, making it a variation of the paddle controller.
Microphone: A few games have made successes in using a headset or microphone as a secondary controller, such as Hey You, Pikachu!, Rock Band, Tom Clancy's ENDWAR and the SOCOM: U.S. Navy SEALs series. The use of these microphones allowed players to issue commands to the game, controlling teammates (as in SOCOM) and other AI characters (Pikachu). The Nintendo DS features a microphone that is built into the system. It has been used for a variety of purposes, including speech recognition (Nintendogs, Brain Age: Train Your Brain in Minutes a Day!), chatting online between and during gameplay sessions (Pokémon Diamond and Pearl), and minigames that require the player to blow or shout into the microphone (Feel the Magic: XY/XX, WarioWare: Touched!, Mario Party DS).
Steel Batallion for the Xbox was bundled with a full dashboard, with 2 joysticks and over 30 buttons, in an attempt to make it feel like an actual mecha simulator.
Fishing rod: the first fishing rod controller appeared as an accessory for the Sega Dreamcast video console for playing SEGA Marine Fishing. Later other games for Playstation console use also a similar controllers.
Floating Interactive Display: since 2003 two companies, IO2Technology from the US and Fogscreen from Finland have developed Minority Report style interactive floating interfaces which display an image projected in mid-air but can be interacted with by finger similar to a touch screen. The IO2Technology version is called the Heliodisplay.
Mind-controlled headset: As of March 24, 2007 a US/Australian company called Emotiv Systems began launching a mind-controlled device for video games based on electroencephalography. It was reported by Wall Street Journal's Don Clark on MSNBC.
PCGamerBike similar to a pair of pedals removed from an exercise bike, then set down in front of a chair & used to precisely control game characters instead.
Optical motion tracking systems such as TrackIR and FreeTrack use a video camera to track an infrared illuminated or emissive headpiece. Small head movements are tracked and then translated into much larger virtual in-game movements, allowing hands-free view control and improved immersiveness.
Mechanical motion tracking systems like Gametrak use cables attached to gloves for tracking position of physical elements in three-dimensional space in real time. The Gametrak mechanism contains a retracting cable reel and a small tubular guide arm from which the cable passes out. The guide arm is articulated in a ball joint such that the arm and ball follow the angle at which the cable extends from the mechanism. The distance of the tracked element from the mechanism is determined through components which measure the rotation of the spool drum for the retracting cable reel, and calculating how far the cable is extended.
Exoskeleton controllers use exoskeleton technology to provide the player with different responses based on the player’s body position, speed of movement, and other sensed data. In addition to audio and visual responses, an exoskeleton controller may provide a controlled resistance to movement and other stimuli to provide realism to the action. This not only lets players feel as if they are actually performing the function, but also helps reinforce the correct muscle pattern for the activity being simulated. The Forcetek XIO is an example of an exoskeleton video game controller.
Instrument panels are simulated aircraft instrument panels, either generic or specific to a real aircraft, that are used in place of the keyboard to send commands to a flight simulation program. Some of these are far more expensive than all the rest of a computer system combined. The panels usually only simulate switches, buttons, and controls, rather than output instrument displays.
Train controls: Other instrument panel like hardware such as train controls have been produced. The "RailDriver" for example is designed to work with Trainz, Microsoft Train Simulator and Kuju Rail Simulator. (as of Jan 2009) it is limited in ease of use by the lack of a Windows API interface for some of the software it is designed to work with. A train controller for a Taito bullet train sim has also been made for the Wii console.
An accessory for the Nintendo Entertainment System (NES) was the R.O.B. (Robotic Operating Buddy). Known in Japan as the Famicom Robot, this accessory was short lived, appearing in only Stack-Up and Gyromite. It was classified a "Trojan horse" during the video game market crash of 1985.[citation needed] R.O.B. appeared in two packages—the NES Deluxe Set (alongside a NES control deck, the NES Zapper, two controllers, Duck Hunt and Gyromite) and the Gyromite set. However short lived, this accessory jumpstarted Nintendo's involvement in the western market. R.O.B. was called by GameSpy the fifth greatest video game marketing move within twenty-five.[citation needed] R.O.B. has been shown in Mario Kart DS for the Nintendo DS as a playable. It also appeared in Super Smash Bros. Brawl not only as a playable character but as the Ancient Minister in the Story Mode, The Subspace Emissary.