Polygonrasterisering

Polygonrasterisering is a fundamental process in computer graphics used to render 3D models. It involves converting vector graphics, which are defined by geometric shapes like polygons, into a raster image composed of pixels. Essentially, it's the process of figuring out which pixels on a screen are covered by a given polygon and what color those pixels should be.

The process typically begins with a polygon defined by its vertices in 3D space. These vertices are then projected onto a 2D plane, representing the screen. The rasterization algorithm then determines the boundaries of the projected polygon. For each pixel within these boundaries, a decision is made whether it falls inside or outside the polygon. This is often done using barycentric coordinates or edge-walking algorithms.

Once a pixel is determined to be inside the polygon, its color is calculated. This involves interpolating color information, texture coordinates, and depth values from the polygon's vertices across the surface of the polygon. Shading models are applied at this stage to determine the final color based on lighting and material properties. The result is a grid of colored pixels that forms the visible representation of the 3D polygon on the 2D screen. This technique is crucial for displaying any 3D scene, from video games to architectural visualizations.