Rasterisation

In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an described in a vector graphics format (shapes) and converting it into a (a series of pixels, dots or lines, which, when displayed together, create the image which was represented via shapes). The rasterized image may then be displayed on a computer display, video display or printer, or stored in a bitmap file format. Rasterization may refer to the technique of drawing 3D models, or the conversion of 2D rendering primitives such as polygons, line segments into a rasterized format. The term "rasterisation" comes . Line drawing algorithm Bresenham's line algorithm is an example of an algorithm used to rasterize lines. Algorithms such as Midpoint circle algorithm are used to render circle onto a pixelated canvas. Rasterization is one of the typical techniques of rendering 3D models. Compared with other rendering techniques such as ray tracing, rasterization is extremely fast and therefore used in most realtime 3D engines. However, rasterization is simply the process of computing the mapping from scene geometry to pixels and does not prescribe a particular way to compute the color of those pixels. The specific color of each pixel is assigned by a pixel shader (which in modern GPUs is completely programmable). Shading may take into account physical effects such as light position, their approximations or purely artistic intent. The process of rasterizing 3D models onto a 2D plane for display on a computer screen ("screen space") is often carried out by fixed function (non-programmable) hardware within the graphics pipeline. This is because there is no motivation for modifying the techniques for rasterization used at render time and a special-purpose system allows for high efficiency. Polygons are a common representation of digital 3D models. Before rasterization, individual polygons are typically broken down into triangles, therefore a typical problem to solve in 3D rasterization is rasterization of a triangle.