[eyal282]

Originally Posted by ayyyyyyylmao nonono, im making visible-check for my plugin, like if i can see any player, i receive they steamid, if i can see noone, i will receive -1

Instead of GetClientEyeAngles use the origin of the target entity.

Instead of RayType_Infinite use RayType_EndPosition ( infinite uses angles and endposition uses another entity's origin ).

Feel free to use filters for invisible things like glasses, and filter both target and client entities.

After filtering:

if(TR_DidHit())
// Player cannot see target player.