/* Backend Functions. */
#define select(A, B, mask) mix(A, B, mask)

bool is_zero(vec2 A)
{
  return all(equal(A, vec2(0.0)));
}

bool is_zero(vec3 A)
{
  return all(equal(A, vec3(0.0)));
}

bool is_zero(vec4 A)
{
  return all(equal(A, vec4(0.0)));
}