1. void main()
    2. {             
    3.     float ratio = 1.00 / 1.52;
    4.     vec3 I = normalize(Position - cameraPos);
    5.     vec3 R = refract(I, normalize(Normal), ratio);
    6.     FragColor = vec4(texture(skybox, R).rgb, 1.0);
    7. }