Youtube channels:
mathew wadstein (lots of blueprint tutorials)
freya holmer (lots of math and shader tutorials)
Stuff about networking:
Cedric Neukirchen (look for his PDF on google or his website)
UI and input:
In general:
EPICs unreal documentation but it’s all over the place (if you don’t know where to look / what questions to ask).
And if you’re looking for features, tools, game mechanics that are fully implemented (game ready), you can take a look at some of my stuff on FAB or Github. From my GitHub you can learn how to implement plugins, C++, blueprints properly.
If you end up using something like a circle spline to snap objects to, then thrown objects would snap to the nearest spline point on X/Y/Z as well. Or, since projectiles rarely have a large lifetime (they despawn at X distance or time), and a map is usually big (so the curve of the world isn’t that noticable), you might just let projectiles travel a straight path (yes, they will move slightly away from the circle in time).
I also wonder how Terraria optimized (and it wraps?) their large tile based map. I think there is a video about how they did it on youtube.