Game terminologies

By Ahmed Badr

Agenda

• RGB• Color cube• Pixel• Color depth• Resolution• Pixel art• BMP• Grayscale

Agenda

• Alpha mask• PCX• JPEG/JPG• Alpha channels• Sprite• Polygon• Vertex• Edge

Agenda

• Model• Face• Mesh• Texture• Tile maps• Texel• Texture Mapping• UV mapping

Agenda

•MinMaps•procedural texture•point sampling•Bilinear interpolation•Tri-linear filtering•anisotropic filtering•Render•Frame

Agenda

•Gouraud shading•Reflection mapping•Specular reflection•Diffuse reflection•Refraction•Bump mapping•Normal mapping•parallax mapping

Agenda

• Lightmap• Ray tracing• Terrain• Height map• Pixel shader• Vertex shader• Cell shader• Game bots

Agenda

• AI

• procedural animation

• Skeletal animation

• Morph target animation

• Collision

• Game engine

• game genre

RGB

• The RGB color model is an additive model in which red, green, and blue (often used in additive light models) are combined in various ways to reproduce other colors.

Color cube

• A color in the RGB color model can be described by indicating how much of each of the red, green and blue color is included. Each can vary between the minimum (no color) and maximum (full intensity). If all the colors are at minimum the result is black. If all the colors at maximum, the result is white.

Pixel

• A pixel (short for picture element, using the common abbreviation "pix" for "picture") is a single point in a graphic image. Each such information element is not really a dot, nor a square, but an abstract sample

Color depth

• Color depth is a computer graphics term describing the number of bits used to represent the color of a single pixel in a bitmapped image.

• This concept is also known as bits per pixel (bpp)

Resolution

• The number of pixels in an image is sometimes called the resolution.

• The higher the resolution the higher the picture quality

• In game industry the same concepts apply but put in mind that high resolution comes at the price of high memory consumption and processing time.

Pixel art

• Pixel art is a form of digital art, created through the use of raster graphics software, where images are edited on the pixel level. Two type of pixel art, Isometric and non isometric.

Isometric

Non Isometric

BMP

• BMP files are usually not compressed, so they are typically much larger than compressed image file formats for the same image. For example, an 800×600 24-bit image will occupy almost 1.4 megabytes

• 800 x 600 x (24/8) = 1.4 MB

Grayscale

• Displayed images of this sort are typically composed of shades of gray, varying from black at the weakest intensity to white at the strongest

Alpha mask

• Used to introduce transparency to areas to the BMP files. A gray scale image is used to describe transparency in a BMP image

PCX

• PCX is an image file format developed by the ZSoft Corporation of Marietta, Georgia, USA. It was the native file format for PC Paintbrush and became one of the first widely accepted DOS imaging standards, although its use has since been succeeded by more sophisticated image formats such as GIF, JPEG, and PNG.

• Advantage: compression without losing quality

JPEG/JPG

• In computing, JPEG is a commonly used method of compression for photographic images

• Advantages: Holds transparency information without the need to an external file

• Disadvantages: destructive compression is used.

Alpha channels

In a 2D image element which stores a color for each pixel, an additional value is stored in the alpha channel containing a value ranging from 0 to 1. A value of 0 means that the pixel does not have any coverage information

Sprite

Sprite is a two-dimensional image or animation that is integrated into a larger scene.

Polygon

In geometry a polygon is a plane figure that is bounded by a closed path or circuit, composed of a finite number of sequential

line segments .

Vertex

a vertex is a corner of an angle

Edge

a connection between two vertices

Model

A model is a fully-3D computer graphic, polygonal object or character used in computer and video games

Face

In geometry, a face of a polyhedron is any of the polygons that make up its boundaries

Mesh

• A polygon mesh or unstructured grid is a collection of vertices and polygons that define the shape of an polyhedral object in 3D computer graphics.

Texture

Texture refers to the properties held and sensations caused by the external surface of objects received through the sense of touch.

Tile maps

• A picture with seamless edges repeated along side in X and Y axis

Texel

texture element The smallest addressable unit of a texture map. When objects in the image are near, one texel is mapped to one or more screen pixels. When objects are distant, multiple texels are averaged into one screen pixel

Texture Mapping

Texture mapping is a method, pioneered by Edwin Catmull, of adding detail, surface texture, or colour to a computer-generated graphic or 3D model

UV mapping

• UV mapping is a 3D modelling process of making a 2D image representing a 3D model. The map transforms the 3D object onto an image known as a texture. In contrast to "X", "Y" and "Z", which are the coordinates for the original 3D object in the modelling space, "U" and "V" are the coordinates of the transformed object. This creates the effect of painting the image onto the surface of the 3D object

MinMaps

A texture mapping technique that uses multiple texture maps, or MIP maps. Each MIP map is half the size of the first one, providing several texture maps for various levels of depth

procedural texture

• An algorithmic way of describing a texture. Unlike a bitmapped texture, in which the texture is represented as a bitmap, a procedural texture describes the texture mathematically. Although not widely used, this method is resolution independent and can create more precise textures, especially if there is great and varying depth to the objects being textured. Procedural textures may be 2D or 3D

• http://www.answers.com/topic/procedural-textures?cat=technology

volumetric texture

• A texture that is described in three dimensions. It can be created as a "stack" of 2D bitmapped textures or as a 3D procedural texture. When an object with volumetric texture is sliced in half, the texture would still be rendered accurately on the inside

• http://www.answers.com/topic/volumetric-texture?cat=technology

point sampling

• Also called "nearest neighbor," it is the simplest form of texture mapping, which is often associated with low-end games and applications that do not demand much realism. An algorithm is used to map a screen pixel to the corresponding point on the texture map. The attributes (color, alpha, etc.) of the nearest texel are then directly applied to the screen pixel. The process is repeated for each pixel forming the object being textured

Bilinear interpolation

• A texture mapping technique that produces a reasonably realistic image, also known as "bilinear filtering" and "bilinear texture mapping." An algorithm is used to map a screen pixel location to a corresponding point on the texture map. A weighted average of the attributes (color, alpha, etc.) of the four surrounding texels is computed and applied to the screen pixel. This process is repeated for each pixel forming the object being textured

• http://www.answers.com/topic/bilinear-interpolation?cat=technology

Tri-linear filtering

• Bilinear filtering has several weaknesses that make it an unattractive choice in many cases: using it on a full-detail texture when scaling to a very small size causes accuracy problems from missed texels, and compensating for this by using multiple mipmaps throughout the polygon leads to abrupt changes in blurriness, which is most pronounced in polygons that are steeply angled relative to the camera.

• trilinear filtering interpolates between the results of bilinear filtering on the two mipmaps nearest to the detail required for the polygon at the pixel

• http://www.answers.com/Trilinear%20filtering

anisotropic filtering

• is a method of enhancing the image quality of textures on surfaces that are at oblique viewing angles with respect to the camera where the projection of the texture appears to be non orthogonal

http://www.answers.com/Anisotropic%20filtering

Render

Rendering is the process of generating an image from a model, by means of computer programs. The model is a description of three dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture and lighting information.

Frame

a frame is one of the many still images which compose the complete moving picture

Gouraud shading

• Gouraud shading, named after Henri Gouraud, is a method used in computer graphics to simulate the differing effects of light and colour across the surface of an object. In practice, Gouraud shading is used to achieve smooth lighting on low-polygon surfaces without the heavy computational requirements of calculating lighting for each pixelhttp://en.wikipedia.org/wiki/Gouraud_shading

Reflection mapping

• reflection mapping is an efficient method of simulating a complex mirroring surface by means of a precomputed texture image. The texture is used to store the image of the environment surrounding the rendered object.

• Types of cube mapping– Standard Environment Mapping– Cube Environment Mapping– HEALPix Environment Mapping

• http://en.wikipedia.org/wiki/Reflection_mapping

Specular reflection

• Specular reflection is the perfect, mirror-like reflection of light

• http://en.wikipedia.org/wiki/Specular_reflection

Diffuse reflection

• Diffuse reflection is the reflection of light from an uneven or granular surface such that an incident ray is seemingly reflected at a number of angles

• http://en.wikipedia.org/wiki/Diffuse_reflection

Refraction

• Refraction is the change in direction of a wave due to a change in its speed. This is most commonly seen when a wave passes from one medium to another. Refraction of light is the most commonly seen example, but any type of wave can refract when it interacts with a medium

• http://en.wikipedia.org/wiki/Refraction

Bump mapping

Bump mapping is a computer graphics technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a heightmap and applied before the illumination calculation is done

Normal mapping

• normal mapping is an application of the technique known as bump mapping

• Normal mapping used to re-detail simplified meshes

• http://en.wikipedia.org/wiki/Image:Normal_map_example.png

parallax mapping

• Parallax mapping is an enhancement of the bump mapping or normal mapping . To the end user, this means that textures such as stone walls, will have more apparent depth with less of an influence on the performance.

• http://en.wikipedia.org/wiki/Parallax_mapping

Lightmap

A light map is a 3D engine light data structure which contains the brightness of surfaces in a video game. Light maps are pre-computed and used for static objects

Ray tracing

Ray tracing is a general technique from geometrical optics of modeling the path taken by light by following rays of light as they interact with optical surfaces

Terrain

• Terrain, or relief, is the third or vertical dimension of land surface.

Height map

A height map or height field is a raster image used to store values, such as surface elevation data, for display in 3D computer graphics

Pixel shader

A pixel shader serves to manipulate a pixel, usually to apply an effect on an image, for example; realism, bump mapping, shadows, and explosion effects.

Vertex shader

A Vertex-Shader serves to manipulate the geometry of an object of a scene. Therefore the form of the object changes and this changes the appearance of the object. With the help of vertex Shader effects as vertex lighting, terrain-/Object-deformation, waves or fish eye perspective are possible

Cell shader

Cell Shading is the "art" of rendering your objects to look like cartoons. Various cartoon effects can be achieved with very little modifications to the original source code.

Game bots

is a robotic computer controlled entity that simulates an online or LAN multiplayer human death match opponent, team death match opponent or a cooperative human player. Computer game bots work via artificial intelligence routines pre-programmed to suit the game map, game rules, game type and other parameters unique to each game

AI

Game artificial intelligence refers to techniques used in computer and video games to produce the illusion of intelligence in the behavior of non-player characters (NPCs). The techniques used typically draw upon existing methods from the academic field of artificial intelligence AI

procedural animation

• A procedural animation is a type of computer animation, used to automatically generate animation in real-time to allow for a more diverse series of actions than could otherwise be created using predefined animations.

• Procedural animation is used to simulate particle systems cloth and clothing, rigid body dynamics, and hair and fur dynamics, as well as character animation

• http://en.wikipedia.org/wiki/Procedural_animation

Skeltal animation

• Skeletal animation, sometimes referred to as rigging, is a technique in computer animation, particularly in the animation of vertebrates, in which a character is represented in two parts: a surface representation used to draw the character (called the skin) and a hierarchical set of bones used for animation only (called the skeleton).

• http://en.wikipedia.org/wiki/Skeletal_animation

Morph target animation (or per-vertex animation)

• Morph target animation (or per-vertex animation) is a method of 3D computer animation that is sometimes used as an alternative to skeletal animation. Morph target animation is stored as a series of vertex positions. In each keyframe of the animation, the vertices are moved to a different position.

• http://en.wikipedia.org/wiki/Morph_target_animation

Collision

•collision means the action of bodies striking or coming together

Game engine

• A game engine is the core software component of a computer video game or other interactive application with real-time graphics. It provides the underlying technologies, simplifies development, and often enables the game to run on multiple platforms

• The core functionality typically provided by a game engine includes a rendering engine (“renderer”) for 2D or 3D graphics, a physics engine or collision detection (and collision response), sound, scripting, animation, artificial intelligence, networking, streaming, memory management, threading, and a scene graph

game genre

• Video games are categorized into genres based on their gameplay

• http://en.wikipedia.org/wiki/Game_genre

References

• http://www.wikipedia.com

• http://www.answers.com/