where is the LIGHTMAP_ON definition?

hi,i want to ask a question about shader. i can see LIGHTMAP_ON or LIGHTMAP_OFF marco definition in many shaders about lightmap,but i could not find the definitin place,where is it or is it build-in unity3d?

thanks for answer!!

usually it’s set by current scene, if you want change it in settings, in unity 5.x, find shader stripping in "Edit->Project Setting->Graphics ", change it to manual and set what you want.

after you baked the scene, LIGHTMAP_ON is automatically defined,


when you delete the baked data, LIGHTMAP_ON is not defined.