// direction facing towards(!) the light
glm::vec3 light_direction = { -1.0f, -3.0f, -2.0f };
// fade out reaches 1/e (0.3679) at 1/fog_density,
// direction facing towards(!) the light
glm::vec3 light_direction = { -1.0f, -3.0f, -2.0f };
// fade out reaches 1/e (0.3679) at 1/fog_density,