Scanline Rendering - Use in Realtime Rendering

Use in Realtime Rendering

The early Evans & Sutherland ESIG line of image-generators (IGs) employed the technique in hardware 'on the fly', to generate images one raster-line at a time without a framebuffer, saving the need for then costly memory. Later variants used a hybrid approach.

The Nintendo DS is the latest hardware to render 3D scenes in this manner, with the option of caching the rasterized images into VRAM.

The sprite hardware prevalent in 1980s games machines can be considered a simple 2D form of scanline rendering.

The technique was used in the first Quake engine for software rendering of environments (but moving objects were Z-buffered over the top). Static scenery used BSP-derived sorting for priority. It proved better than Z-buffer/painter's type algorithms at handling scenes of high depth complexity with costly pixel operations (i.e. perspective-correct texture mapping without hardware assist). This use preceded the widespread adoption of Z-buffer-based GPUs now common in PCs.

Sony experimented with software scanline renderers on a second Cell processor during the development of the PlayStation 3, before settling on a conventional CPU/GPU arrangement.