View source for UserWiki:DavidJCobb/Glitch Glossary

Here is a glossary for [[glitch]]-related terms. It is sorted alphabetically.

==Actor==
Though the term varies from game to game, "'''actor'''" is generally used to refer to anything that is not terrain -- any interactive or mobile object, ranging from [[Grunts]] to [[Deployable Lookout Towers]] to the [[John-117|Master Chief]] himself. [[Weapon]]s and [[vehicle]]s are also actors.

==Array==
An '''array''' is a data structure consisting of a list of numerically-indexed values.

==[[Wikipedia:Hidden surface determination#Backface culling|Backface culling]]==
'''Backface culling''' is a 3D rendering technique that causes polygons to only be visible from one side. It can also cause polygons to only be ''solid'' from one side -- one-way walls.

==Bit==
A '''bit''' is a single zero or one, in binary.

==Byte==
A '''byte''' is eight [[#Bit|bits]]. A variable capable of holding one byte can hold any value between 0 and 255, inclusive; a [[#Sign bit|signed]] variable can hold between -128 and +128.

==Clipping==
Used in some circles to refer to a flaw in [[#Collision detection|collision detection]]. Collision detection checks the current frame of animation for collisions, with no regard for the previous frame. If an object is moving extremely fast, it may be in front of a wall in one frame, and behind the wall in the next frame of animation. As collision detection engines cannot check between frames, the game will never "notice" that the object went through the wall.

==Collision==
A '''collision''' is any contact between two objects, in 2D or 3D games.
===Collision detection===
'''Collision detection''' refers to both the act of detecting a collision and the program or mechanism used to do so.
===Collision mesh===
A '''collision mesh''' is the 3D shape used to check for collisions. Generally, an object's collision mesh is not as ornate or detailed as its actual 3D model; a vase may have a very detailed 3D representation, but its collision mesh may be just a simple cylinder.

Such separate collision meshes are used to simplify physics calculations and collision detections.

==Death [[Wikipedia:Plane (Geometry)|plane]]==
See ''[[#Kill barrier|kill barrier]]''.

==Exception==
An '''exception''' is any error that occurs during gameplay. Generally, only fatal exceptions -- those that crash the entire game or program -- are noticeable.

==Flag==
A '''flag''' is a simple on/off or true/false value used to signify some state or condition. Specifically, a flag is a [[#Variable|variable]] that holds a single [[#Bit|bit]].

==Hall of mirrors==
A rendering glitch that occurs when ''nothing'' is drawn on a part of the screen. When this occurs, whatever was on that part of the screen in the previous frame remains there, creating a "'''hall of mirrors'''" or "afterimage" effect. An example can be seen in [[Wikipedia:File:Noclip-doom2.gif|this screenshot from Doom]].

==Hexadecimal==
'''Hexadecimal''', also referred to as '''hex''', is base-16 encoding. It is commonly used as an intermediate numerical form, between binary (base-2) and decimal (base-10). Valid digits in hexadecimal are 0-9 and A-F. In the same way that any data can be represented in binary, any data can be represented in hex.

Hex is typically used for memory addresses and numerical variable values, which is why it is frequently used in cheat code devices. On a side note, it is also used to format colors in [[Wikipedia:HTML|HTML]] and [[Wikipedia:Cascading Style Sheets|CSS]].

==Infinite void==
An '''infinite void''' is the empty space surrounding all levels and all maps in all 3D games. As maps do not have a fixed shape or size, they are always surrounded by voids. In some games, voids have a solid color; in other games, such as ''Halo 3'', voids exhibit a [[#Hall of mirrors|hall of mirrors]] effect when seen.

Contrary to popular belief, and despite what the name implies, infinite voids are not infinite. In ''Halo 3'', "infinite" voids are cubic, being no larger than 100,000 world units along any of the standard three axes.

==Invisible wall==
{{Main|Invisible Walls}}
An '''invisible wall''', typically used by developers to block access to certain areas, and to keep the player inside of the level boundaries.

==Kill barrier==
{{Main|Invisible Walls}}
A '''kill barrier''' is a plane or surface that kills the player upon contact. Typically used to facilitate bottomless pits and falling deaths, they are very abundant in ''Halo'', being used to supplement nearly every [[#Invisible wall|invisible wall]] in the game.

==Level boundaries==
The '''level boundaries''' are the edges of the playable area -- that is, the edges of the normal area of a map that the player is allowed to explore. The term is typically used to refer to the collection of [[#Invisible wall|invisible walls]] that surround the playable area.

==Loading point==
A '''loading point''' is a point at which most of the area behind the player is removed from RAM, and the area in front of the player is loaded into RAM. In non-linear games and levels, players can pass back and forth between a loading point, "toggling" the areas on either side. In the ''Halo'' series, loading points are indicated by a "'''Loading... done.'''" message shown above the [[Motion tracker]].

Typically, loading points do not load or unload level geometry, but they ''do'' load and unload textures and actors. In most games, bypassing a loading point generally allows a player to access the area beyond it in a semi-loaded state, with most surfaces being invisible and no actors being present.

''Halo'' appears to use a slightly different system, as demonstrated by the ability to access areas that should be unloaded in a usable state using the [[Time Travel Glitch]].

==Moonjump==
The term "'''moonjump'''" is used to refer to any event where an object very rapidly ascends to an astonishing and physically impossible height. Moonjumps occur, for example, in [[Super Bouncing|Super Bounces]].

==Object==
In computing, an '''object''' is a data structure that is composed of '''properties'''. A property can be thought of as a "sub-[[#Variable|variable]]".

==Overflow==
Numerical '''overflow''' occurs when a [[#Variable|variable]] is not large enough to hold its value. Variables are limited in size, so it is possible to store a value larger than what the variable can hold. Variable sizes tend to be powers of two; common limits for [[#Sign bit|unsigned]] variables are 255 and 65535.

When overflow occurs, it is typically handled in one of the following ways.
*A fatal [[#Exception|exception]] occurs, and an error is thrown.
*The value is rounded to the largest value the variable can hold.
*The value "wraps" around. If a variable that can only hold 255 is assigned a value of 257, the variable's value becomes 1 (257 - 255 - 1).

==[[Wikipedia:Polygon (computer graphics)|Polygon]]==
A '''polygon''' is a triangular or rectangular shape, typically combined with others to create 3D objects.
===Polygon seam===
A '''polygon seam''' is an edge where two polygons meet. Seams that form large, sharp angles can sometimes be glitched through or even walked on, as though they were a single flat surface.

==Sign bit==
All numbers are stored in binary -- base-2, zeroes and ones. When a variable needs to hold a negative value, it is given a '''sign bit''' -- one of its [[#Bit|bits]] is converted into the sign bit. If the sign bit is a 1, the value is negative; if the sign bit is a 0, the value is positive. The allocation of an extra bit cuts the variable's maximum value in half.

==Skybox==
A '''skybox''' is a 3D shape placed around the level. The shape, typically a cube or a sphere, is given a sky texture to simulate a real environment with a real atmosphere. In ''Halo 3'', skyboxes tend to be far larger than the actual playable area of their containing maps.

==String==
In computing, a '''string''' is a text value.

==Stutter==
"'''Stutter'''" is used to describe the phenomenon in which an object rapidly jumps back and forth between two very close positions. It can often happen when running into a very small, sharp polygon seam.

==[[Wikipedia:Variable|Variable]]==
A '''variable''' is a name that is used to refer to a value, similar to mathematics. In computing, variables are limited in size; if a program attempts to store a value that is too big for the "target" variable to hold, [[#Overflow|overflow]] occurs.

Variables can also hold [[#String|text]], [[#Array|lists]], and [[#Object|objects]].

==Void==
See ''[[#Infinite void|infinite void]]''.

==Warp==
In tile-based games like [[Wikipedia:Pokemon|Pokemon]], "'''warp'''" is used to refer to invisible objects placed on tiles that cause the player to teleport to another location when stepped on. Doors in such games do not change the player's position; the invisible warps placed over them do.