Contrast, shadow density and colour depth — the remaster pass.
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 srcTex = texture2D(uTex, vUv); vec3 c = srcTex.rgb; // Pull the black point down so shadows have real density instead of sitting // grey. Renormalised so highlights don't move with it. float bp = uDepth * 0.18; c = clamp((c - bp) / max(1e-3, 1.0 - bp), 0.0, 1.0); // Filmic S-curve. smoothstep IS an S by construction, so this always // steepens the midtones and rolls off softly at both ends rather than // hard-clipping the way a straight multiply would. Applied twice at the top // of the range for a steeper curve, with no branch. float t = uPunch * 2.0; vec3 s = mix(c, smoothstep(vec3(0.0), vec3(1.0), c), clamp(t, 0.0, 1.0)); s = mix(s, smoothstep(vec3(0.0), vec3(1.0), s), clamp(t - 1.0, 0.0, 1.0)); // A contrast curve desaturates as it compresses — put the colour back. float l = dot(s, vec3(0.299, 0.587, 0.114)); gl_FragColor = vec4(clamp(mix(vec3(l), s, 1.0 + uPunch * 0.45), 0.0, 1.0), srcTex.a); }