POINT P = *I ;
Option A: Write a function that will determine whether the point is on the screen (not hard) and make it accept a vec2
Option B: Declare P as vec2 instead of POINT. ( Which will probably mess up the next line)
Option C: Declare your list as POINTS instead of vec2s.
Option D: Simply declare P as is. Then assign P.x to *i.x and P.y to *i.y