Korea
Korea is a region in East Asia. Since 1948, it has been divided between two distinct sovereign states: South Korea. Korea consists of the Korean Peninsula, Jeju Island, several minor islands near the peninsula. Korea is bordered by China to the northwest, Russia to the northeast, neighbours Japan to the east by the Korea Strait and the Sea of Japan. During the first half of the 1st millennium, Korea was divided between the three competing states of Baekje and Silla, together known as the "Three Kingdoms of Korea". In the second half of the 1st millennium and Goguryeo were conquered by Silla, leading to the "Unified Silla" period. Meanwhile, Balhae formed in the north following the collapse of Goguryeo. Unified Silla collapsed into three separate states due to civil war, ushering in the Later Three Kingdoms. Toward the end of the 1st millennium Goryeo, a revival of Goguryeo, defeated the two other states and unified the Korean Peninsula as one single state. Around the same time, Balhae collapsed and its last crown prince fled south to Goryeo.
Goryeo, whose name developed into the modern exonym "Korea", was a cultured state that created the world's first metal movable type in 1234. However, multiple invasions by the Mongol Empire during the 13th century weakened the nation, which agreed to become a vassal state after decades of fighting. Following military resistance under King Gongmin which ended Mongol political influence in Goryeo, severe political strife followed, Goryeo fell to a coup led by General Yi Seong-gye, who established Joseon in 1392; the first 200 years of Joseon were marked by relative peace. During this period, the Korean alphabet was created by Sejong the Great in the 15th century and there was increasing influence of Confucianism. During the part of the dynasty, Korea's isolationist policy earned it the Western nickname of the "Hermit Kingdom". By the late 19th century, the country became the object of imperial design by the Empire of Japan. After the First Sino-Japanese War, despite the Korean Empire's effort to modernize, it was annexed by Japan in 1910 and ruled by Imperial Japan until the end of World War II in August 1945.
In 1945, the Soviet Union and the United States agreed on the surrender of Japanese forces in Korea in the aftermath of World War II, leaving Korea partitioned along the 38th parallel. The North was under Soviet occupation and the South under U. S. occupation. These circumstances soon became the basis for the division of Korea by the two superpowers, exacerbated by their inability to agree on the terms of Korean independence; the Communist-inspired government in the North received backing from the Soviet Union in opposition to the pro-Western government in the South, leading to Korea's division into two political entities: North Korea, South Korea. Tensions between the two resulted in the outbreak of the Korean War in 1950. With involvement by foreign troops, the war ended in a stalemate in 1953, but without a formalized peace treaty; this status contributes to the high tensions. Both governments of the two Koreas claim to be the sole legitimate government of the region. "Korea" is the modern spelling of "Corea", a name attested in English as early as 1614.
Korea was transliterated as Cauli in The Travels of Marco Polo, of the Chinese 高麗. This was the Hanja for the Korean kingdom of Goryeo, which ruled most of the Korean peninsula during Marco Polo's time. Korea's introduction to the West resulted from trade and contact with merchants from Arabic lands, with some records dating back as far as the 9th century. Goryeo's name was a continuation of Goguryeo the northernmost of the Three Kingdoms of Korea, known as Goryeo beginning in the 5th century; the original name was a combination of the adjective go with the name of a local Yemaek tribe, whose original name is thought to have been either *Guru or *Gauri. With expanding British and American trade following the opening of Korea in the late 19th century, the spelling "Korea" appeared and grew in popularity; the name Korea is now used in English contexts by both North and South Korea. In South Korea, Korea as a whole is referred to as Hanguk; the name references Samhan, referring to the Three Kingdoms of Korea, not the ancient confederacies in the southern Korean Peninsula.
Although written in Hanja as 韓, 幹, or 刊, this Han has no relation to the Chinese place names or peoples who used those characters but was a phonetic transcription of a native Korean word that seems to have had the meaning "big" or "great" in reference to leaders. It has been tentatively linked with the title khan used by the nomads of Central Asia. In North Korea, China and Japan, Korea as a whole is referred to as. "Great Joseon" was the name of the kingdom ruled by the Joseon dynasty from 1393 until their declaration of the short-lived Great Korean Empire in 1897. King Taejo had named them for the earlier Kojoseon, who ruled northern Korea from its legendary prehistory until their conquest in 108 BC by China's Han Empire; this go is the Hanja 古 and
Role-playing video game
A role-playing video game is a video game genre where the player controls the actions of a character immersed in some well-defined world. Many role-playing video games have origins in tabletop role-playing games and use much of the same terminology and game mechanics. Other major similarities with pen-and-paper games include developed story-telling and narrative elements, player character development, complexity, as well as replayability and immersion; the electronic medium increases combat resolution speed. RPGs have evolved from simple text-based console-window games into visually rich 3D experiences. Role-playing video games use much of the same terminology and game mechanics as early tabletop role-playing games such as Dungeons & Dragons. Players control a central game character, or multiple game characters called a party, attain victory by completing a series of quests or reaching the conclusion of a central storyline. Players explore a game world, while engaging in combat. A key feature of the genre is that characters grow in power and abilities, characters are designed by the player.
RPGs challenge a player's physical coordination or reaction time, with the exception of action role-playing games. Role-playing video games rely on a developed story and setting, divided into a number of quests. Players control one or several characters by issuing commands, which are performed by the character at an effectiveness determined by that character's numeric attributes; these attributes increase each time a character gains a level, a character's level goes up each time the player accumulates a certain amount of experience. Role-playing video games typically attempt to offer more complex and dynamic character interaction than what is found in other video game genres; this involves additional focus on the artificial intelligence and scripted behavior of computer-controlled non-player characters. The premise of many role-playing games tasks the player with saving the world, or whichever level of society is threatened. There are twists and turns as the story progresses, such as the surprise appearance of estranged relatives, or enemies who become friends or vice versa.
The game world tends to be set in a fantasy or science fiction universe, which allows players to do things they cannot do in real life and helps players suspend their disbelief about the rapid character growth. To a lesser extent, settings closer to near future are possible; the story provides much of the entertainment in the game. Because these games have strong storylines, they can make effective use of recorded dialog and voiceover narration. Players of these games tend to appreciate long cutscenes more than players of faster action games. While most games advance the plot when the player defeats an enemy or completes a level, role-playing games progress the plot based on other important decisions. For example, a player may make the decision to join a guild, thus triggering a progression in the storyline, irreversible. New elements in the story may be triggered by mere arrival in an area, rather than completing a specific challenge; the plot is divided so that each game location is an opportunity to reveal a new chapter in the story.
Pen-and-paper role-playing games involve a player called the gamemaster who can dynamically create the story and rules, react to a player's choices. In role-playing video games, the computer performs the function of the gamemaster; this offers the player a smaller set of possible actions, since computers can't engage in imaginative acting comparable to a skilled human gamemaster. In exchange, the typical role-playing video game may have storyline branches, user interfaces, stylized cutscenes and gameplay to offer a more direct storytelling mechanism. Characterization of non-player characters in video games is handled using a dialog tree. Saying the right things to the right non-player characters will elicit useful information for the player, may result in other rewards such as items or experience, as well as opening up possible storyline branches. Multiplayer online role-playing games can offer an exception to this contrast by allowing human interaction among multiple players and in some cases enabling a player to perform the role of a gamemaster.
Exploring the world is an important aspect of many RPGs. Players will walk through, talking to non-player characters, picking up objects, avoiding traps; some games such as NetHack and the FATE series randomize the structure of individual levels, increasing the game's variety and replayability. Role-playing games where players complete quests by exploring randomly generated dungeons and which include permadeath are called roguelikes, named after the 1980 video game Rogue; the game's story is mapped onto exploration, where each chapter of the story is mapped onto a different location. RPGs allow players to return to visited locations. There is nothing left to do there, although some locations change throughout the story and offer the player new things to do in response. Players must acquire enough power to overcome a major challenge in order to progress to the next area, this structure can be compared to the boss characters at the end of levels in action games; the player must complete a linear sequence of certain quests in order to reach the end of the game's story, although quests in some games such as Arcanum or Geneforge can limit o
Isometric video game graphics
Isometric video game graphics are graphics employed in video games and pixel art where the viewpoint is angled to reveal facets of the environment that would not be visible from a top-down perspective or side view, thereby producing a three-dimensional effect. Despite the name, isometric computer graphics are not truly isometric—i.e. The x, y, z axes are not oriented 120° to each other. Instead, a variety of angles are used; the terms "3/4 perspective", "2.5D", "pseudo-3D" are sometimes used, although these terms can possess different meanings in other contexts. Once common, isometric projection became less common with the advent of more powerful 3D graphics systems, as games began to focus more on action and individual characters. However, video games using isometric projection have seen somewhat of a resurgence in recent years on Kickstarter. In the fields of computer and video games and pixel art, the technique has become popular because of the ease with which 2D sprite- and tile-based graphics can be made to represent a 3D gaming environment.
Because parallelly projected objects do not change size as they move about the game field, there is no need for the computer to scale sprites or do the complex calculations necessary to simulate visual perspective. This allowed older 8-bit and 16-bit game systems to portray large 3D areas and easily. And, while the depth confusion problems of parallel projection can sometimes be a problem, good game design can alleviate this. There are gameplay advantages to using an isometric or pseudo-isometric perspective in video games. For instance, compared to a purely top-down game, they add a third dimension, opening up new avenues for aiming and platforming. Secondly, compared to a first- or third-person game, they allow you to more field and control a larger number of additional units, such as a full party of characters in a role-playing game. Further, they may alleviate situations where a player may become distracted from a game's core mechanics by having to manage an unwieldy 3D camera. I.e. the player can focus on playing the game itself, not on moving and rotating the camera.
Lastly, there is an artistic advantage. Though not limited to isometric video games, pre-rendered 2D graphics can possess a higher fidelity and use more advanced techniques than may be possible on available computer hardware with 3D hardware acceleration enabled. To modern CGI used in motion pictures, graphics can be rendered once on a powerful super computer or render farm, displayed on less powerful consumer hardware, such as tablet computers and Web browsers; this means that static pre-rendered isometric graphics look better compared to their real-time rendered counterparts, may age better over time compared to their peers. However, this advantage may be less pronounced now. One disadvantage of pre-rendered graphics is that, as display resolutions continue to increase, the static 2D images need to ideally be re-rendered to keep pace, or otherwise suffer from pixelation; this is not always possible, however. The new developer opted for simple 2D graphics scaling, or "zooming", without re-rendering the game's sprites, as they were lacking the game's original creative art assets.
Changing the resolution of a real-time rendered game is trivial, in comparison. The projection used in videogames deviates from "true" isometric due to the limitations of raster graphics. Lines in the x and y directions would not follow a neat pixel pattern if drawn in the required 30° to the horizontal. While modern computers can eliminate this problem using anti-aliasing, earlier computer graphics did not support enough colors or possess enough CPU power to accomplish this. So instead, a 2:1 pixel pattern ratio would be used to draw the x and y axis lines, resulting in these axes following a 26.565° angle to the horizontal. Therefore, this form of projection is more described as a variation of dimetric projection, since only two of the three angles between the axes are equal to each other. While the history of computer games saw some true 3D games as soon as the early 1970s, the first video games to use the distinct visual style of isometric projection in the meaning described above were arcade games in the early 1980s.
The use of isometric graphics in video games began with the appearance of Sega's Zaxxon, released as an arcade game in January 1982. It is an isometric shooter, it is one of the first video games to display shadows. Another early isometric game is Q*bert, which Warren Davis and Jeff Lee began programming in April 1982 and released in October/November 1982. Q*bert shows a static pyramid in an isometric perspective, with the player controlling a character which can jump around on the pyramid; the following year in March 1983, the isometric platformer arcade game Congo Bongo was released, running on the same hardware as Zaxxon. It allows the player character to move around in bigger isometric levels, including true three-dimensional climbing and falling; the same is possible in the arcade title Marble Madness, released in 1984. At this time, isometric games were no
Shooter game
Shooter games are a subgenre of action video game, which test the player's speed and reaction time. It includes many subgenres that have the commonality of focusing on the actions of the avatar using some sort of weapons; this weapon is a gun or some other long-range weapon. A common resource found in many shooter games is ammunition. Most the purpose of a shooter game is to shoot opponents and proceed through missions without the player character being killed or dying. A shooting game is a genre of video game where the player has limited spatial control of his or her character, the focus is entirely on the defeat of the character's enemies using weaponry. Shoot'em ups are a specific subgenre of shooters wherein the player may move up and down and left and right around the screen firing straight forward. Shoot'em ups share common gameplay, but are categorized by viewpoint; this includes fixed shooters such as Space Invaders and Galaxian. This genre includes "run and gun" games which emphasize greater maneuvering or jumping, such as Thexder and Metal Slug.
Shooting gallery games include light gun games, although many can be played using a regular joypad and an on-screen cursor to signify where the bullets are being aimed. When these debuted, they were played from a first-person perspective, with enemy fire that occurred anywhere on the screen damaging or killing the player; as they evolved away from the use of light guns, the player came to be represented by an on-screen avatar someone on the bottom of the screen, who could move and avoid enemy attacks while returning fire. These sorts of shooters always utilize horizontal scrolling to the right to indicate level progression, with enemies appearing in waves from predestined locations in the background or from the sides. One of the earliest examples is the 1985 arcade game Shootout produced by Data East. A specific subgenre of this type of game is the Cabal shooter, named for the game Cabal, in which the player controls an on-screen avatar that can run and jump around the screen in addition to being able to aim their gun.
Other games in this subgenre include Blood Bros. Dynamite Duke, NAM-1975, Wild Guns, Sin and Punishment; as light gun games became more prevalent and started to make use of 3D backgrounds, such as the Time Crisis or House of the Dead series, these sorts of games fell out of popular production, but many like Blood Bros. still have their fanbase today. Other notable games of this category include Laser Invasion. Light gun shooters are shooting gallery games that use a pointing device for computers and a control device for arcade and video games; the first light guns appeared following the development of light-sensing vacuum tubes. It was not long before the technology began appearing in arcade shooting games, beginning with the Seeburg Ray-O-Lite in 1936; these early light gun games used small targets onto. If the beam struck the target, a "hit" was scored. Modern screen-based light guns work on the opposite principle—the sensor is built into the gun itself, the on-screen target emit light rather than the gun.
The first light gun of this type was used on the MIT Whirlwind computer, which used a similar light pen. Like rail shooters, movement is limited in light-gun games. Notable games of this category include the 1974 and 1984 versions of Wild Gunman, Duck Hunt for the NES, the Virtua Cop series, Time Crisis series, House of the Dead series, Resident Evil: The Umbrella Chronicles & Darkside Chronicles. First-person shooters are characterized by an on-screen view that simulates the in-game character's point of view. While many rail shooters and light-gun shooters use a first-person perspective, they are not included in this category. Notable examples of the genre include Doom, Half-Life, Counter-Strike, GoldenEye 007, Medal of Honor, Call of Duty, TimeSplitters, Team Fortress 2 and Halo. Third-person shooters are characterized by a third-person camera view that displays the player character in his/her surroundings. Notable examples of the genre include the Tomb Raider series, Syphon Filter, Max Payne, SOCOM, Star Wars: Battlefront, Resident Evil 4, Gears of War, Splatoon.
Third person shooter mechanics are incorporated into open-world adventure and sandbox games, including the Elder Scrolls series and the Grand Theft Auto franchise. Hero shooters are a variation of multiplayer first- or third-person arena-based shooters, where players, split among two or more teams, select from pre-designed "hero" characters that each possess unique attributes, skills and other activated abilities. Hero shooters encourage teamwork between players on a team, guiding players to select effective combinations of hero characters and coordinate the use of hero abilities during a match; such games are inspired by multiplayer online battle arena games. A popular hero shooter is Team
Third generation of video game consoles
In the history of computer and video games, the third generation began on July 15, 1983, with the Japanese release of two systems: the Nintendo Family Computer and Sega SG-1000. This generation marked the end of the North American video game crash, a shift in the dominance of home video games from the United States to Japan. Handheld consoles were not a major part of this generation, although the Game & Watch line from Nintendo had started in 1980 and the Milton Bradley Microvision came out in 1979; some features that distinguish third generation consoles from most second generation consoles include: D-pad game controllers. Screen modes with resolutions up to 256×240 or 320×200. Tile-based playfields with smooth multi-directional hardware scrolling. Advanced hardware scrolling, including per-pixel scrolling, multi-directional scrolling, diagonal scrolling, line-scrolling. 25–32 colors on screen, from a palette of 53–256 colors. 64–100 sprites on screen, each with 4–16 colors and 8×8 to 16×16 pixel sizes.
Up to five channel mono PSG audio. The best-selling console of this generation was the NES/Famicom from Nintendo, followed by the Sega Master System, the Atari 7800. Although the previous generation of consoles had used 8-bit processors, it was at the end of this generation that home consoles were first labeled, marketed, by their "bits"; this came into fashion as next-generation 16-bit systems like the Sega Mega Drive/Genesis were marketed in order to differentiate between the generations of consoles. In Japan and North America, this generation was dominated by the Famicom/NES, while the Master System dominated the European and Brazilian markets; the end of the 3rd generation of video games was marked by 8-bit consoles becoming obsolete in terms of their graphics and processing power. The Family Computer became popular in Japan during this era, crowding out the other consoles in this generation; the Famicom's Western counterpart, the Nintendo Entertainment System, dominated the gaming market in North America, thanks in part to its restrictive licensing agreements with developers.
This marked a shift in the dominance of home video games from the United States to Japan, to the point that Computer Gaming World described the "Nintendo craze" as a "non-event" for American video game designers as "virtually all the work to date has been done in Japan." The company had an estimated 65% of 1987 hardware sales in the console market. The popularity of the Japanese consoles grew so that in 1988 Epyx stated that, in contrast to a video game-hardware industry in 1984 that the company had described as "dead", the market for Nintendo cartridges was larger than for all home-computer software. Nintendo sold seven million NES systems in 1988 as many as the number of Commodore 64s sold in its first five years. Compute! reported that Nintendo's popularity caused most computer-game companies to have poor sales during Christmas that year, resulting in serious financial problems for some, after more than a decade making computer games, in 1989 Epyx converted to console cartridges. By 1990 30% of American households owned the NES, compared to 23% for all personal computers, peer pressure to have a console was so great that the children of computer-game developers demanded them despite parents' refusal and the presence of state-of-the-art computers and software at home.
As Computer Gaming World reported in 1992, "No matter how fast your 486 is, you still can't play Super Mario XVII on it. The kids who don't have access to videogames are as culturally isolated as the kids in our own generation whose parents refused to buy a TV". Nintendo's market domination, while overwhelming in sheer number of units sold, was not global. Although the NES dominated the market in Japan and North America, Sega's Master System made large inroads in Europe and Brazil, where the NES was never able to break its grip; the Atari 7800 had a successful life in the United States. Sega was Nintendo's main competitor during the era in terms of market share for console units sold. Unlike the NES, Sega's SG-1000 had little to differentiate itself from earlier consoles such as the ColecoVision and contemporary computers such as the MSX, despite the lack of hardware scrolling, the SG-1000 was able to pull off advanced scrolling effects, including parallax scrolling in Orguss and sprite-scaling in Zoom 909.
In 1985, Sega's Master System incorporated hardware scrolling, alongside an increased colour palette, greater memory, pseudo-3D effects, stereoscopic 3-D, gaining a clear hardware advantage over the NES. However, the NES would still continue to dominate the important North American and Japanese markets, while the Master System would gain more dominance in the emerging European and South American markets. In the following generation, Nintendo would introduce the Game Boy, which single-handedly solidified and proceeded to dominate the scattered handheld market for 15 years. While the Game Boy product line was incrementally updated every few years, until the Game Boy Micro and Nintendo DS, the Game Boy Color, all Game Boy products were backwards compatible with the original released in 1989. Since the Game Boy's release, Nintendo had dominated the handheld market. Additionally two popular 8-bit computers, the Commodore 64 and Ams
Virtual camera system
In 3D video games, a virtual camera system aims at controlling a camera or a set of cameras to display a view of a 3D virtual world. Camera systems are used in videogames where their purpose is to show the action at the best possible angle; as opposed to film makers, virtual camera system creators have to deal with a world, interactive and unpredictable. It is not possible to know. To solve this issue, the system relies on certain rules or artificial intelligence to select the most appropriate shots. There are three types of camera systems. In fixed camera systems, the camera does not move at all and the system displays the player's character in a succession of still shots. Tracking cameras, on the other hand, follow the character's movements. Interactive camera systems are automated and allow the player to directly change the view. To implement camera systems, video game developers use techniques such as constraint solvers, artificial intelligence scripts, or autonomous agents. In video games, "third-person" refers to a graphical perspective rendered from a fixed distance behind and above the player character.
This viewpoint allows players to see a more characterized avatar, is most common in action games and action adventure games. Games with this perspective make use of positional audio, where the volume of ambient sounds varies depending on the position of the avatar. There are three types of third-person camera systems: the "fixed camera systems" in which the camera positions are set during the game creation. In this kind of system, the developers set the properties of the camera, such as its position, orientation or field of view, during the game creation; the camera views will not change dynamically, so the same place will always be shown under the same set of views. An early example of this kind of camera system can be seen in Alone in the Dark. While the characters are in 3D, the background on which they evolve has been pre-rendered; the early Resident Evil games are notable examples of games. The God of War series of video games is known for this technique. One advantage of this camera system is that it allows the game designers to use the language of film.
Indeed, like filmmakers, they have the possibility to create a mood through camerawork and careful selection of shots. Games that use this kind of technique are praised for their cinematic qualities; as the name says, a tracking camera follows the characters from behind. The player does not control the camera in any way - he/she cannot for example rotate it or move it to a different position; this type of camera system was common in early 3D games such as Crash Bandicoot or Tomb Raider since it is simple to implement. However, there are a number of issues with it. In particular, if the current view is not suitable, it cannot be changed since the player does not control the camera. Sometimes this viewpoint causes difficulty when a character stands face out against a wall; the camera may end up in awkward positions. This type of camera system is an improvement over the tracking camera system. While the camera is still tracking the character, some of its parameters, such as its orientation or distance to the character, can be changed.
On video game consoles, the camera is controlled by an analog stick to provide a good accuracy, whereas on PC games it is controlled by the mouse. This is the case in games such as The Legend of Zelda: The Wind Waker. Interactive camera systems are difficult to implement in the right way, thus GameSpot argues that much of the Super Mario Sunshine' difficulty comes from having to control the camera. The Legend of Zelda: The Wind Waker was more successful at it - IGN called the camera system "so smart that it needs manual correction". One of the first games to offer an interactive camera system was Super Mario 64; the game had two types of camera systems between. The first one was a standard tracking camera system except that it was driven by artificial intelligence. Indeed, the system was "aware" of the structure of the level and therefore could anticipate certain shots. For example, in the first level, when the path to the hill is about to turn left, the camera automatically starts looking towards the left too, thus anticipating the player's movements.
The second type allows the player to control the camera to Mario's position. By pressing on the left or right buttons, the camera rotates around Mario, while pressing up or down moves the camera closer or away from Mario. There is a large body of research on; the role of a constraint solver software is to generate the best possible shot given a set of visual constraints. In other words, the constraint solver is given a requested shot composition such as "show this character and ensure that he covers at least 30 percent of the screen space"; the solver will use various methods to try creating a shot that would satisfy this request. Once a suitable shot is found, the solver outputs the coordinates and rotation of the camera, which can be used by the graphic engine renderer to display the view. In some camera systems, if no solution can be found, constraints are relaxed. For
3D rendering
3D rendering is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images on a computer. 3D renders may include non-photorealistic rendering. Rendering is the final process of creating the actual 2D animation from the prepared scene; this can be compared to taking a photo or filming the scene after the setup is finished in real life. Several different, specialized, rendering methods have been developed; these range from the distinctly non-realistic wireframe rendering through polygon-based rendering, to more advanced techniques such as: scanline rendering, ray tracing, or radiosity. Rendering may take from fractions of a second to days for a single image/frame. In general, different methods are better suited for either photo-realistic rendering, or real-time rendering. Rendering for interactive media, such as games and simulations, is calculated and displayed in real time, at rates of 20 to 120 frames per second. In real-time rendering, the goal is to show as much information as possible as the eye can process in a fraction of a second.
The primary goal is to achieve an as high as possible degree of photorealism at an acceptable minimum rendering speed. In fact, exploitations can be applied in the way the eye'perceives' the world, as a result, the final image presented is not that of the real world, but one close enough for the human eye to tolerate. Rendering software may simulate such visual effects as depth of field or motion blur; these are attempts to simulate visual phenomena resulting from the optical characteristics of cameras and of the human eye. These effects can lend an element of realism to a scene if the effect is a simulated artifact of a camera; this is the basic method employed in games, interactive worlds and VRML. The rapid increase in computer processing power has allowed a progressively higher degree of realism for real-time rendering, including techniques such as HDR rendering. Real-time rendering is polygonal and aided by the computer's GPU. Animations for non-interactive media, such as feature films and video, are rendered much more slowly.
Non-real time rendering enables the leveraging of limited processing power in order to obtain higher image quality. Rendering times for individual frames may vary from a few seconds to several days for complex scenes. Rendered frames are stored on a hard disk can be transferred to other media such as motion picture film or optical disk; these frames are displayed sequentially at high frame rates 24, 25, or 30 frames per second, to achieve the illusion of movement. When the goal is photo-realism, techniques such as ray tracing, path tracing, photon mapping or radiosity are employed; this is the basic method employed in artistic works. Techniques have been developed for the purpose of simulating other occurring effects, such as the interaction of light with various forms of matter. Examples of such techniques include particle systems, volumetric sampling and subsurface scattering; the rendering process is computationally expensive, given the complex variety of physical processes being simulated.
Computer processing power has increased over the years, allowing for a progressively higher degree of realistic rendering. Film studios that produce computer-generated animations make use of a render farm to generate images in a timely manner. However, falling hardware costs mean that it is possible to create small amounts of 3D animation on a home computer system; the output of the renderer is used as only one small part of a completed motion-picture scene. Many layers of material may be rendered separately and integrated into the final shot using compositing software. Models of reflection/scattering and shading are used to describe the appearance of a surface. Although these issues may seem like problems all on their own, they are studied exclusively within the context of rendering. Modern 3D computer graphics rely on a simplified reflection model called Phong reflection model. In refraction of light, an important concept is the refractive index. In most 3D programming implementations, the term for this value is "index of refraction".
Shading can be broken down into two different techniques, which are studied independently: Surface shading - How light spreads across a surface Reflection/Scattering - How light interacts with a surface at a given point Popular surface shading algorithms in 3D computer graphics include: Flat shading: A technique that shades each polygon of an object based on the polygon's "normal" and the position and intensity of a light source. Gouraud shading: Invented by H. Gouraud in 1971, a fast and resource-conscious vertex shading technique used to simulate smoothly shaded surfaces. Phong shading: Invented by Bui Tuong Phong, used to simulate specular highlights and smooth shaded surfaces. Ref
