# Feedback / Ping-Pong Buffers

**Track:** Advanced Shaders & GPU — Advanced Creative Coding — proposed (50)
**Framework / surface:** GLSL
**Level:** Hard
**Prerequisites:** The Fragment Toolkit Beyond UV, Images & Pixels as Arrays

**In one line:** Persistent trails, blur, GPU Game of Life via double buffering.

## Theory, aesthetics & inspiration

State persists on the GPU when a render target's output becomes the next frame's input, but a texture cannot be read and written simultaneously, so two buffers alternate roles—the ping-pong pattern. Decaying the previous frame yields motion trails and long-exposure smears; iterating a blur kernel diffuses; sampling a pixel's neighbors and applying a rule runs Conway's Game of Life entirely in parallel. The same substrate hosts reaction-diffusion, the Gray-Scott model whose spots and stripes echo Alan Turing's 1952 theory of morphogenesis. The aesthetic is emergent and temporal: simple local rules accumulate across frames into organic pattern, decay, and self-organizing structure no single pass could produce.