拜耳抖动背景

Write a full-screen fragment shader that first computes a continuous grayscale value from fbm noise, an SDF shape mask and expanding ring ripples. Snap fragment coordinates to a coarse pixel grid so each 'pixel' is several screen pixels. Compare the grayscale value against the corresponding entry of an 8x8 Bayer threshold matrix (indexed by pixel coordinate mod 8) and output either the ink or paper color. On click, push the click position and timestamp into a small uniform array so each ripple's radius grows with time and fades out.