Hardware Heritage
Interference patterns, often taking the form of concentric rings or Moire fringes, were a staple of the Amiga and PC demo scenes. These effects leveraged the machine's ability to perform high-speed XOR operations or pre-computed distance lookups to create complex, hypnotic visuals from the interaction of simple geometric primitives.
PC Tables
Software interference on PC required pre-calculated distance tables. By summing two distance values from different moving centers and using the result as a palette index, programmers created complex moire fringes.
Amiga XOR
Amiga coders famously used the Blitter's XOR mode to overlap circular bitplanes. This produced high-contrast, flickering interference patterns that became a signature of the Amiga style.
Visual Aliasing
This effect exploits the human brain's desire to find patterns in overlapping discrete structures. It remains one of the most hypnotic effects in the lab.
Interference
Summed geometric waves.
Legacy ASM (XOR)
; Blitter XOR operation move.w #$0B00,BLTCON0 move.l #Buffer1,BLTAPTH move.l #Buffer2,BLTCPTH move.l #Screen,BLTDPTH
Modern GLSL
float d1 = length(uv - p1) * 40.0; float d2 = length(uv - p2) * 40.0; col = vec3(mod(floor(d1) + floor(d2), 2.0));