Graphic Styles

Graphics are visual representations of what the computer is processing. Graphics are displayed on a display unit (Monitor, TV, Projector, etc...) by manipulating pixels. Once the display unit has gathered all the pixels it needs (Generally for Computers, either 480,000 or 789,504 pixels), it displays them on the screen, by piecing them together like a puzzle.

There are two methods of displaying graphics on a screen. The first is interlacing, in which every other scanline of the graphics is displayed simultaneously. This saves bandwidth in older video cord standards while keeping an acceptable video quality. However, interlacing can create distortions in the displayed image. The second method is progressive scan. In this method, all the scanlines that make up the image are displayed per frame, allowing for a higher quality image. It also removes the distortions found with interlacing. However, progressive scan requires a high-bandwidth digital connection.

2D Graphics (Sprites)
During the early days of video games, game graphics could only be displayed in 2D. Landscapes, characters, effects, and menus were all created as two-dimensional images known as sprites. Each sprite is a losslessly-encoded image, usually a PNG or similar format image in modern 2D games. Sprites can be manipulated with enough processing power. Each character sprite has frames of animation that have to be individually drawn, much like cels in a traditional cartoon. In this sense, sprite-based video games are an extension of cel-based animation. Most sprites are low-resolution, especially those from older games, but newer sprite-based games, such as Rayman Origins, use high-resolution sprites to achieve an animated-cartoon look that even cel-shading cannot achieve.

Meshes


A mesh is a collection of vertices, edges and faces that form a wireframe, which defines the shape of a 3D model. Vertices,points in 3D space, are the most fundamental layer in a mesh. Two connected vertices form an edge and a face is built when three vertices are connected to form a triangle. Once four egdes are connected together to define a face, you will get a quad-face, simply called a quad. However, any face consisting of more than three edges is usually referred to as a polygon. While modifying all of these three layers of a model, a 3D-Artist can create any shape they want. While most 3D applications support n-sided polygons, most real-time applications(Game-Engines) require the mesh to be composed out of triangles. The mesh is triangulated for performance reasons since a Triangle is easier to calculate than a Quad. Furthermore, it is important to watch out for the amount of triangles used in a 3D game environment while trying to keep it at a low rate. The more triangles, the more calculations have to be made by the engine which will inevitably result in a lower frame rate at some point.

Texture Mapping


Texture Mapping is the fundamental method of texturing a 3D model in any medium that uses 3D computer graphics. Textures are simple image files which are wrapped around a 3D model using UVW coordinates. If you imagine a large piece of paper wrapped around a statue which is used to colorize it, then you have a more or less close representation of the process. When laying out UVW coordinates, the 3D model is broken into pieces and the wireframe is stretched out onto a flat plane so that every face in 3D space gets assigned an unique location in 2D space which is required since an image is only two dimensional. Textures in games are usually square and their resolution is usually a power of two, such as 256x256, 512x512, 1024x1024, etc. However, resolutions like 1024x512 or similar are also possible. This is done for several technical reasons, like saving RAM and to support older hardware. The higher the resolution of a texture, the more RAM is occupied, so keeping texture sizes at a reasonable level is important in 3D games.

Texture Maps
In modern games a single mesh gets assigned more than just one Texture Map. There are several kinds of different maps all serving a specific purpose. Here is a list of the different types used in the making of theThe Legend of Zelda games.

Diffuse Map
A Diffuse Map is just a simple Color Map. It will give the 3D model its main color, making it the most basic map. Most, if not all, meshes in a 3D game will be colorized using this kind of map. Diffuse Maps are usually 24-bit images that display the whole RGB spectrum, however, using a 8-bit or 2-bit image is possible too.

Specular Map
A Specular Map is responsible for the specular highlights and defines how shiny the object is when reacting to a light source. This is usually done by using a 8-bit image (grayscale) where lighter colors define shiny spots and deeper colors define dull spots on the texture. Meaning, when you want to make a shiny metal texture, you would use a very bright tone. Using a 24-bit image (RGB) also possible. With this, you can colorize specular highlights which can add a little bit of realism or aesthetic to your mesh. However, this comes at the cost of more memory usage since a 24-bit image uses more RAM than a 8-bit image.

This Map or an Environment Map plus Bump mapping was probably used for Medli's Harp in The Wind Waker.

Bump Map or Normal Map
Bump Maps are used to create realistic lighting effects that simulate a complex surface on a simple one. This technique is used to save CPU power. Bump Maps or sometimes called Height Maps were used in the early days of 3D games. Back then, Bump Maps were 8-bit images and worked similar to Specular Maps, except that in this case whites define spots which are raised and blacks define spots that are depressions on the texture. The Bump Map is unable to create realistic lightning effects corresponding to the positioning of the light source, which is why the traditional Bump Map has been replaced by the more powerful Normal Map, nowadays.

A Normal Map is a 24-bit image known for it's purple-blueish color. The Normal Map is able to react realistically to lightning environments by showing highlights and shadows on the model corresponding to the position of a light source. A Normal Map and several other maps are usually rendered in a process called 'Map Baking'. A highly detailed mesh and the final game mesh will be needed for this process. The 'high-poly' mesh can be made out of millions of polygons so that the artist can model out smaller details. The final game mesh is then built around this high-poly mesh to encompass it. Once the game mesh is ready for baking, the 3D application will project the details of the high-poly mesh onto the UVW coordinates of the game mesh which will result in highly accurate textures. In the end, the game mesh can look exactly like its high-poly equivalent, depending on the mesh, the technical restrictions and the skill of the artist.

This effect was probably used for Medli's Harp in The Wind Waker and in Skyward Sword on some meshes.

Displacement Map
Displacement mapping is a more advanced version of bump mapping that simulates actual complex polygonal surfaces. The Displacement Map is usually a 8-bit image and works exactly like the Bump Map, except that raised spots and depressions are not faked through lighnting but rather by offsetting the surface of the mesh itself.While this offset can act as a real change to the meshes topology in most 3D applicatons, this is usually not the case in real-time applications like games. In games this offset is usually just faked by offsetting the texture depending on the camera angle.

Emissive Map
This Map defines which parts of a texture should glow in the dark. Whites on the texture define glowy areas and blacks define areas that do not glow in the dark. A 8-bit is used in most cases but using a 24-bit image as a Emissive Map is possible and helps colorizing glowing effects. This can be used to create magic effects or to create simple things like textures for fire.

Environment(Reflection) Map
Environment mapping is an effect used to achieve highly realistic reflective effects without much CPU calculations. This is done by "mapping" the contents of the room containing the reflective object to the object, similarly to texture mapping. The Environnment Map in games acts just as another texture(Cube Map) which is projected onto a faked environment(a cube or a sphere) which is then put around the mesh that is supposed to reflect said texture. This enables realistic and believable reflections without much work or CPU power. The mesh holding the Cube Map may be visble or not visible to the camera. In most cases it is not visible to the camera and to the player and so it is only visible to the mesh showing the reflections.

This Map was used extensively in Ocarina of Time for the Close Ups of most inventory items or things like swords and the Mirror Shield.

Light Mapping
Light mapping is a certain kind of mapping. A Light Map is an image containing lightning information, so it simply shows areas that are covered in shadows or are illuminated by light. Blacks define shadows and whites define areas that have been lit. Light mapping is mainly used for environments like terrain or smaller environment meshes and is pre-calculated, therefore it is mainly used for static meshes that will never move. So characters or objects animated by physics won't use Light mapping because shadow and light-effects are static with this method and will look out of place when the object should move into a different lightning environment. Light Mapping is used to save recources since the calculation of dynamic light and shadows is very demanding on the hardware.

Realistic Shading
Realistic shading is the most prevalent lighting method in all of 3D-based media. Realistic lighting is used to achieve a realistic look in a video game. It is usually accompanied with highly detailed textures and large amounts of effects. Realistic shading was the first type of lighting system used after the "simple lighting" of early 3D games. Realistic lighting is relatively easy to achieve with programming, leading to its widespread use in video games. Realistic lighting itself can range from simple "soft" lighting seen in early 3D games to complex "ultra-realistic" lighting seen in today's games. Fully realistic lighting can only be achieved with non-real-time ray-tracing, which requires so much computer power that real-time ray tracing at an acceptable framerate is probably not possible for the next decade. As such, realistic shading, which only approximates how light works, is currently used.

Cel-Shading
Cel-shading is an alternative lighting method used to simulate an animated cartoon, or in the case of Skyward Sword, a painting. Cel-shading was first used for pre-rendered computer animations in the 1980s. Animation companies like Disney switched from traditional hand animation to 3D-based cel-shading rendering engines for cartoons, such as Deep Canvas, in the 1990s. The first use of cel-shading in video games was Jet Set Radio for the Sega Dreamcast. Cel-shading is more intensive than realistic shading methods, as it requires more calculations to be able to render the cartoon-like graphics correctly. This is because cel-shading achieves a flat look, and the graphics engine has to calculate how a surface is lit from different angles so that it looks flat. Cel-shading is merely a different type of lighting, and uses the same type of assets as ordinary games, though sometimes, an area of a model is not textured because it can more easily be colored in real-time by the hardware during rendering. Textures are usually simple and made up of solid colors to achieve a cartoon-like look, though more detailed textures may be used to simulate the backgrounds of said cartoons, which can be as detailed as high-quality paintings.

Effects
Effects are used to achieve realism or to increase visual appeal in video games.

Reflections
Reflections are achieved in two main ways: Environment mapping and Double Rendering. Environment mapping is the more popular of the two methods, as it requires less time and computation than Double Rendering.


 * Double Rendering
 * Double Rendering is the act of rendering an exact mirror copy of a 3D scene behind or beneath a mirror to produce reflective effects. While this achieves a more accurate look and enables easier placement of the :player in a mirror image, the method comes at a high cost because it requires rendering twice as many polygons as is required with reflection-mapped reflections.

Particles
Particles are used in video games to simulate rain, snow, fire, smoke, sparks, or fog. Usually, particles obey the laws of physics, though this is not always so. Particles can be made to clump together in a cloud, float around diffusely or can be emitted from meshes. Particles may also be used to simulate hair, though this is not used in the Zelda series. One particle is nothing more than a flat square mesh applied with a texture. Their scale, dimensions and movement can be randomized and manipulated at real-time.

Cloth Simulation
Cloth simulation is a physics effect that simulates the effect of gravity or wind on a soft, floppy material, usually cloth or hair. The Wind Waker was the first Zelda game to use such physics in great amounts, though Ocarina of Time was the first Zelda game to use it at all to animate Ganondorf's cape.

Shaders and Post-Processing
The most basic task of a shader is to define how a object reacts to light. Nowadays, a shader is also used for much more complex tasks like special effects, in that it modifies or enhances the way an image or object is originally rendered. This means that shader is a pretty generic term for many effects, so it is not surprising that it finds use in many 3D Games. Shaders can be used for tinting something in a different color, animated magic effects flowing over a mesh or rendering objects semi-transparent making them look like water with moving ripples on them.

Post-Processing is pretty much just a shader applied to the game camera. So it can be compared to camera filters in the real world, however, Post-Processing is capable of more complicated effects than just colorizing the whole scene.

Bloom
Bloom is a lighting effect that simulates the high intensity of light coming directly from a light source or is reflected off of a reflective surface. The light will look blurry or gleaming on objects emitting or reflecting it at high intensity. Twilight Princess uses this effect to a great degree, and is a source of dislike for the game.

Lens Flare
Lens flare in video games is the simulation of the internal reflections of a camera lens, to increase realism. Its first Zelda debut was in Ocarina of Time. Lens flare is usually colored, and also accompanies "digital camera light compensation" effects.

Digital Camera Light Compensation
Digital camera light compensation is an effect in video games that simulates the darkening of an image when a digital camera is pointed into a bright light source. It is a rather rare effect, as most developers choose not to use this effect to portray the video game's camera as the eyes of a person, rather than an artificial image sensor. The distinction between digital camera light compensation and imitation of the human eye can be seen in The Wind Waker. In the game, when the sun is directly facing the camera in the normal camera mode, the image darkens according to digital camera light compensation. In first-person view mode, where the player is looking through Link's eyes, digital camera light compensation does not appear, because the camera is imitating the human eye.

Depth-of-Field Blur
Depth-of-field blur is the imitation of an out-of-focus camera. It was first used in the Zelda series in The Wind Waker, where it also served as a smoothing filter. Depth-of-field blur usually occurs only in the distance, but in rare circumstances, objects in the foreground may be blurred. Depth-of-field blur can be manipulated in real-time to simulate a camera focusing in and out, or to draw attention to foreground and background objects.

Motion Blur
Motion blur is the simulation of blurring caused by fast-moving objects captured by a camera. This effect was used to a great extent in Majora's Mask, despite the Nintendo 64's limited capabilities.

Image Distortion
Image distortion is the distortion of all or part of a rendered image to achieve some effect. It is most commonly used to simulate the convection currents caused by intense heat from flames or lava, and sometimes used to "simulate" an underwater scene (though in real life, images do not distort underwater.) Distortion may also be used to show an invisible object or certain types of magic. The Wind Waker and Twilight Princess used distortion in great amounts, though strangely, Skyward Sword did away with all heat-based distortions.

Tone-Mapping
Tone Mapping is the manipulation of the final image, so that it can be displayed a certain way on every display unit. LCD Screens are brighter then plasma screens, so if the console is set to LCD Screen mode, then the hardware will darken the output image. Tone Mapping is used to ensure that the image remains identical on all display screens.

TEV Pipeline
The TEV (Texture EnVironment) pipeline is a feature of the Nintendo GameCube (and by extension. the Wii) that can apply special effects to the final rendered graphics of a game and even program shaders, even though the GameCube and the Wii do not support programmable shaders. This feature was most prominently used in Star Wars Rogue Squadron II: Rogue Leader for the effect used by spacecraft targeting computers. The TEV pipeline may also have been used for the Wolf Sense mode in Twilight Princess.