fog_density_handle = program.UniformLocation("fog_density");
Activate();
program.Uniform(light_direction_handle, glm::vec3(1.0f, 3.0f, 2.0f));
program.Uniform(light_color_handle, glm::vec3(1.0f));
fog_density_handle = program.UniformLocation("fog_density");
Activate();
program.Uniform(light_direction_handle, glm::vec3(1.0f, 3.0f, 2.0f));
program.Uniform(light_color_handle, glm::vec3(1.0f));