rasterize

Rasterize means converting vector or geometric data into a bitmap image made of pixels. In computer graphics, it turns primitives such as triangles, lines, and points into a grid of pixels and assigns each pixel a color via shading, texturing, and lighting. The rasterizer determines which pixels a primitive covers and typically works in screen space after projection.

In a typical pipeline, a primitive is transformed to screen space, clipped to the view volume, and then rasterized to produce fragments for covered pixels. The rasterizer uses scan conversion and barycentric coordinates to interpolate vertex attributes (color, texture coordinates, depth). A depth buffer stores visibility, and a fragment shader computes the final color. Optional anti-aliasing techniques, such as multisample anti-aliasing, improve edge quality by resolving subpixel coverage.

Rasterization is central to real-time rendering due to speed and predictability on graphics hardware. It does not inherently simulate all light transport and is often paired with shading, precomputed lighting, or hybrid methods. A common limitation is aliasing on diagonal edges or fine details, mitigated by anti-aliasing, higher resolution buffers, or supersampling. It also underpins font rendering and vector graphics when outlines are rasterized at a target resolution.

Compared with runtime vector rendering, rasterization produces a fixed pixel grid, suitable for displays and raster formats. The term is often used broadly to describe converting any vector description into a raster image for frames, fonts, or raster-based output.