Constant webxr::glwindow::SPHERICAL_FRAGMENT_SHADER

const SPHERICAL_FRAGMENT_SHADER: &str = "
  #version 330 core
  layout(location=0) out vec4 color;
  uniform sampler2D image;
  in vec2 lon_lat;
  void main() {
    vec3 direction = vec3(
      sin(lon_lat.x)*cos(lon_lat.y),
      sin(lon_lat.y),
      cos(lon_lat.x)*cos(lon_lat.y)
    );
    vec2 vTexCoord;
    if ((direction.y > abs(direction.x)) && (direction.y > abs(direction.z))) {
      // Looking up
      vTexCoord.x = direction.z / (direction.y*6.0) + 5.0/6.0;
      vTexCoord.y = direction.x / (direction.y*4.0) + 1.0/4.0;
    } else if ((direction.y < -abs(direction.x)) && (direction.y < -abs(direction.z))) {
      // Looking down
      vTexCoord.x = direction.z / (direction.y*6.0) + 1.0/6.0;
      vTexCoord.y = -direction.x / (direction.y*4.0) + 1.0/4.0;
    } else if (direction.z < -abs(direction.x)) {
      // Looking back
      vTexCoord.x = -direction.y / (direction.z*6.0) + 3.0/6.0;
      vTexCoord.y = -direction.x / (direction.z*4.0) + 1.0/4.0;
    } else if (direction.x < -abs(direction.z)) {
      // Looking left
      vTexCoord.x = -direction.z / (direction.x*6.0) + 1.0/6.0;
      vTexCoord.y = -direction.y / (direction.x*4.0) + 3.0/4.0;
    } else if (direction.x > abs(direction.z)) {
      // Looking right
      vTexCoord.x = -direction.z / (direction.x*6.0) + 5.0/6.0;
      vTexCoord.y = direction.y / (direction.x*4.0) + 3.0/4.0;
    } else {
      // Looking ahead
      vTexCoord.x = direction.x / (direction.z*6.0) + 3.0/6.0;
      vTexCoord.y = direction.y / (direction.z*4.0) + 3.0/4.0;
    }
    color = texture(image, vTexCoord);
  }
";