Computer graphics studies manipulation of visual and geometric information using computational techniques. It focuses on themathematical andcomputational foundations of image generation and processing rather than purelyaesthetic issues. Computer graphics is often differentiated from the field ofvisualization, although the two fields have many similarities.
There are several international conferences and journals where the most significant results in computer graphics are published. Among them are theSIGGRAPH andEurographics conferences and theAssociation for Computing Machinery (ACM) Transactions on Graphics journal. The joint Eurographics andACM SIGGRAPH symposium series features the major venues for the more specialized sub-fields: Symposium on Geometry Processing,[1] Symposium on Rendering, Symposium on Computer Animation,[2] and High Performance Graphics.[3]
As in the rest of computer science, conference publications in computer graphics are generally more significant than journal publications (and subsequently have lower acceptance rates).[4][5][6][7]
Successive approximations of a surface computed using quadric error metrics
The subfield of geometry studies the representation of three-dimensional objects in a discrete digital setting. Because the appearance of an object depends largely on its exterior,boundary representations are most commonly used. Two dimensionalsurfaces are a good representation for most objects, though they may be non-manifold. Since surfaces are not finite, discrete digital approximations are used.Polygonal meshes (and to a lesser extentsubdivision surfaces) are by far the most common representation, although point-based representations have become more popular recently (see for instance the Symposium on Point-Based Graphics).[8] These representations areLagrangian, meaning the spatial locations of the samples are independent. Recently,Eulerian surface descriptions (i.e., where spatial samples are fixed) such aslevel sets have been developed into a useful representation for deforming surfaces which undergo many topological changes (withfluids being the most notable example).[9]
The subfield of animation studies descriptions for surfaces (and other phenomena) that move or deform over time. Historically, most work in this field has focused on parametric and data-driven models, but recentlyphysical simulation has become more popular as computers have become more powerful computationally.
Rendering generates images from a model. Rendering may simulatelight transport to create realistic images or it may create images that have a particular artistic style innon-photorealistic rendering. The two basic operations in realistic rendering are transport (how much light passes from one place to another) and scattering (how surfaces interact with light).
Rendering subfields include:
Transport describes how illumination in a scene gets from one place to another.Visibility is a major component of light transport.
Scattering: Models ofscattering (how light interacts with the surfaceat a given point) andshading (how material properties vary across the surface) are used to describe the appearance of a surface. In graphics these problems are often studied within the context of rendering since they can substantially affect the design ofrendering algorithms. Descriptions of scattering are usually given in terms of abidirectional scattering distribution function (BSDF). The latter issue addresses how different types of scattering are distributed across the surface (i.e., which scattering function applies where). Descriptions of this kind are typically expressed with a program called ashader. (There is some confusion since the word "shader" is sometimes used for programs that describe localgeometric variation.)
