-static const Vec3 grid_color = Vec3(1.0, 0.3, 1.0);
-static const Vec3 mid_color = Vec3(0.4, 0.1, 0.8);
-static const Vec3 horiz_color = Vec3(0.8, 0.1, 1.0);
-static const Vec3 zenith_color = Vec3(0.2, 0.2, 0.2);
-static const Vec3 fog_color = Vec3(0.12, 0.12, 0.12);