Vector Graphics

Overview

Before raster displays filled screens with pixels, vector monitors drew images using electron beams tracing lines directly onto phosphor screens. The result: razor-sharp, infinitely-resolvable lines that glowed with distinctive intensity, decaying as they aged. Games like Asteroids, Tempest, and Star Wars used vector graphics to create visuals impossible on contemporary raster hardware — true 3D wireframes, smooth scaling, sharp curves.

Vector display peaked from 1977 to about 1985 in arcades. Atari, Cinematronics, Sega, and Vectrex (the home console) drove the format. Raster hardware caught up by the mid-80s, raster could fill in colour and texture, and the maintenance cost of vector monitors became uneconomic.

Fast facts

Technology: CRT beam directly traces lines (deflection-based drawing rather than scanning).
Peak era: 1979-1983 (arcade); Vectrex (1982-84) was the home outlier.
Advantage: Sharp lines, smooth movement, true wireframe 3D, distinctive aesthetic.
Limitation: No filled areas, refresh rate drops with object count, monitors expensive to maintain.

How vector displays work

A standard CRT has its electron beam scanning left-to-right, top-to-bottom in a fixed raster pattern, painting whatever colour the timing controller selects at each point. A vector CRT instead aims its beam directly at the line's start point, sweeps to the end point at controlled velocity, and either lights the phosphor (line drawn) or doesn't (move). No scanning — the beam follows the picture.

Process	Description
Beam positioning	Direct electron beam to the line's start point via X/Y deflection
Line drawing	Sweep beam to the end point, with the gun on
Intensity control	Vary beam current to control brightness
Refresh	Repeat every line, every refresh cycle (typically 30-60 Hz)

Each line drawn takes a small amount of time. The more lines per frame, the lower the achievable refresh rate. Asteroids might have 100 lines on screen and refresh comfortably at 60 Hz; Star Wars with hundreds of lines drops to ~30 Hz when scenes are full.

Advantages

Benefit	Result
Resolution	Theoretically infinite — no pixel grid
Smooth movement	No pixel stepping; rotation looks continuous
3D wireframe	True polygon edges with no rasterisation cost
Distinctive look	Glowing lines that fade slightly between refreshes
Efficient drawing	Only the lines need drawing; empty space is free

Limitations

Drawback	Impact
No filled areas	Wireframe-only; can't render solid surfaces
Brightness limits	Phosphor takes time to recharge; very bright displays burn-in
Refresh rate	Drops with object count — busy scenes flicker
Maintenance	Specialised monitors, expensive to repair
Limited colour	Most vector games are monochrome; colour vector hardware (Atari Color XY) was rare and expensive
Phosphor burn-in	Static images literally etch into the screen

Classic vector games

Title	Year	Company	Notes
Space Wars	1977	Cinematronics	One of the first commercial vector arcade games; based on PDP-1's Spacewar!
Asteroids	1979	Atari	The defining vector game; vector physics matched vector display
Lunar Lander	1979	Atari	Mountainscape physics simulator
Battlezone	1980	Atari	First-person tank combat in 3D wireframe
Tempest	1981	Atari	Cylindrical playfield; Color XY hardware (rare colour vector)
Star Wars	1983	Atari	Hi-resolution colour vector; iconic Death Star trench run
Major Havoc	1983	Atari	Late vector classic
Space Duel	1983	Atari	Multi-ship variant of Asteroids
Spy Hunter II	1987	Bally Midway	Late vector — combined raster + vector

Vectrex — vector at home

The Vectrex (1982-1984) was the only major home console to use a vector display. GCE / Milton Bradley shipped it with a built-in 9-inch monochrome vector CRT and overlay sheets to add coloured backgrounds. Around 30 games released. Dedicated cult following continues — modern Vectrex homebrew is active, original units fetch high prices.

Vector to raster transition

Factor	Influence
Colour limitations	Raster offered far more colour options
Maintenance costs	Vector arcade cabinets were costly to keep running; operators preferred raster
Visual expectations	By 1985, players expected filled, textured graphics
Polygon raster	Hard Drivin' (1989) showed raster could match vector's 3D ambitions
Falling cost of raster CRTs	Mass production made raster cheaper than custom vector hardware

Legacy

The vector aesthetic is unmistakable and survives in deliberate revivals:

Influence	Example
Aesthetic revivals	Geometry Wars (2005), Tempest 4000 (2018)
Indie retro	Vectorpark, PolyBranch, various GMTK / Ludum Dare entries
Demoscene	Vector productions still common at Revision, Assembly
Modern tools	Vector-style shaders in Unity / Unreal recreate the bloom-and-fade look
Education	MAME preserves vector games via vector emulation in the host's raster display

Emulation challenges

Emulating vector games on raster displays is technically interesting:

Bloom and fade — vector lines bloom outward and decay; faking this on a sharp LCD requires shader work.
Phosphor persistence — vectors blur slightly between frames; a literal raster emulation looks too sharp.
Refresh-rate variation — vector games run slower when the screen is busy. Emulators can preserve or normalise this.
MAME's vector mode preserves the original beam timing and applies CRT-shader bloom to approximate the original look.

Lines of light