Every pixel forced to pure black or white at one cutoff.
GLSL fragment shader
The effect's own code. The uniforms and helpers above it — uTex, uFeedback, the depth proxy, the frame ring, depthAt(), timeAt() — are the same header every Ether-MOSH shader opens with, and are documented once on the registry rather than reprinted on all 143 pages.
void main(){ vec4 c = texture2D(uTex, vUv); float lum = dot(c.rgb, vec3(0.299, 0.587, 0.114)); float v = smoothstep(uCut - uSoft - 0.001, uCut + uSoft + 0.001, lum); gl_FragColor = vec4(vec3(v), c.a); }