function sizeToGlsl(size) {
  const array = toSize(size);
  return arrayToGlsl(array);
}
Normalizes and converts a number or array toa `vec2` array compatible with GLSL.
@param {number|import('../size.js').Size} size Size.
@return {string} The color expressed in the `vec4(1.0, 1.0, 1.0, 1.0)` form.