Colophon

/** Returns the film simulation recorded in a Fuji maker note, or null if unknown. */
export function parseFilmSim(note: Uint8Array | undefined | null): FilmSim | null {
  if (!note) return null;
  const tags = readFujiTags(note);

  const saturation = tags.get(TAG_SATURATION);
  if (saturation !== undefined) {
    const mono = monochromeFromSaturation(saturation);
    if (mono) return mono;
  }

  const mode = tags.get(TAG_FILM_MODE);
  if (mode !== undefined) return FILM_MODES[mode] ?? null;

  // Colour shots with no FilmMode tag were taken on the default, Provia.
  return saturation !== undefined ? "Provia" : null;
}

/**
 * The globe rotation (Euler XYZ) that puts a lat/lng dead centre, north up.
 * First spin around Y to bring the point onto the YZ plane, then tilt
 * around X by the latitude to bring it level with the camera.
 */
export function rotationToFace(lat: number, lng: number): { x: number; y: number }

export const arcFragment = /* glsl */ `
  uniform vec3 uColor;
  uniform float uDraw;
  uniform float uOpacity;
  uniform float uBase;
  varying float vT;
  void main() {
    float drawn = step(vT, uDraw);
    float head = smoothstep(uDraw - 0.12, uDraw, vT) * drawn * step(uDraw, 0.999);
    float alpha = mix(uBase, 0.9 + head * 0.1, drawn);
    gl_FragColor = vec4(uColor + head * 0.5, alpha * uOpacity);
  }
`;