Lyrically, the song is often considered to be a direct tribute to Syd Barrett. However, on the documentary The Story of Wish You Were Here, Gilmour and Waters separately describe the original concept that differs from this interpretation. Waters, who mainly wrote the lyrics complementing Gilmour’s initial riff idea and subsequent joint composition, describes the lyrics as being directed at himself. Gilmour, on the other hand, recognises that he never performs the song without remembering Syd Barrett. Waters later adds that the song is nevertheless open to interpretation.
I thought that shine on you crazy diamond was for Syd. And this one is more generic loss.
https://en.wikipedia.org/wiki/Wish_You_Were_Here_(Pink_Floyd_song)
Cool. I also looked up to Shine On You Crazy Diamond and the front page says:
And goes on to mostly talk about Syd. Lots of cool stuff.