Predator (1987) camo sketch for ShaderBooth (https://shaderbooth.com/)

camo.glsl

// by rileyjshaw
// inspired by the camo effect in predator (1987)
void main() {
  vec3 color = getCam(uv);
  
  vec2 dir = uv - faceCenter;
  float lenDir = length(dir);
  if (lenDir < 1e-5) {
    dir = vec2(0.0, 1.0); // avoid divide-by-zero at exact center
  } else {
    dir /= lenDir; // it looks cool if you comment this out!
  }
  
  vec2 uvNearerFaceCenter = uv - dir * 100.0 * pixel;
  float face = getFace(uv) + getFace(uvNearerFaceCenter);
  if (face > 0.0) {
    vec2 target = uv + dir * (20.0 * pixel); // grab the color 20px away from your face center
    color = getPrevious(target);
  }

  gl_FragColor = vec4(color.x, color.y * 1.08, color.z, 1.0);
}