Thanks a lot, Martin! You have spotted my mistake. So I have modified my remark on the number 3 as below:
3, in BlenderGuru’s video, the value on the “From Max” is more negative than the value on the “From Min”, so in this case we have:
“From Max” < “From Min”
Hence, for any input value < “From Max”, the output of that input value will be clamped to 1, which means to turn the light on.
For any input value > “From Min”, the output of that input value will be clamped to 0, which means to turn the light off.
Therefore, the input values from the bright side of the Earth are Not ignored. Instead, all outputs of the corresponding input values from the bright side are clamped to 0, so that no light is turned on on the bright side of the Earth anymore.
