Hardware Heritage
Feedback trails, or "motion persistence," utilized the lack of a screen clear to create trails of movement. By carefully managing the decay of pixels over time, programmers could turn a single moving point into a complex, organic-looking structure that blurred the line between math and art.
PC Buffer Reuse
On PC, feedback was achieved by not clearing the VGA segment 0xA000. Programmers would draw the new frame directly over the old one, often with a "fade" pass that subtracted 1 from every byte.
Amiga Accumulation
Amiga coders used the Blitter to blend the previous frame's bitplanes with the current one. This allowed for hardware-accelerated transparency and "ghosting" effects.
Temporal Logic
By not clearing the screen, the display turns the spatial grid into a temporal record, where pixel intensity represents the movement history of objects.
Feedback Trails
Smearing time across the pixels.
Legacy C (Fade)
// Decay loop
for (i=0; i < 64000; i++) {
if (screen[i] > 0) screen[i]--;
}
Modern GLSL
vec4 now = draw_scene(); vec4 last = texture(lastFrame, uv); gl_FragColor = mix(now, last, 0.95);