# Luminace, RGB, and SMPT ST 2084 EOTF

I need a point clarified. According to wikipedia, SMPT ST 2084 EOTF is this:

I've seen this equation implemented in game engines where for L they feed the channels RGB, each of which is 0 to 10,000 and normalize them. Am confused because luminance from what I understand is supposed to be one quantity instead of 3. I understood luminance to be kind'a like speed in physics, and the RGB is the "direction" vector. Is it really correct to plug the RGB linear channels in into L (the "linear optical luminance") in this equation, or am I misunderstanding something? The way I think of it, we need to compute the luminance from the RGB triplet, and then plug that value into L, then from V we compute colors.

Where is my thinking wrong?

Thanks.

We have relative luminance, which is the luminance we use when talking about colours and can be calculated with $$Y=0.2126R+0.7152G+0.0722B$$