NewProjectileDirect()

static Projectile Terraria.Projectile.NewProjectileDirect ( IEntitySource spawnSource, Vector2 position, Vector2 velocity, int type, int damage, float knockback, int owner = -1, float ai0 = 0f, float ai1 = 0f, float ai2 = 0f )

inlinestatic

This particular overload uses a Vector2 instead of X and Y to determine the actual spawn position and a Vector2 to dictate the initial velocity. The return value is the actual Projectile instance rather than the index of the spawned Projectile within the F:Terraria.Main.projectile array.
A short-hand for

Main.projectile[Projectile.NewProjectile(...)]

Definition at line 93078 of file Projectile.cs.

    {
        //IL_0006: Unknown result type (might be due to invalid IL or missing references)
        //IL_000c: Unknown result type (might be due to invalid IL or missing references)
        //IL_0012: Unknown result type (might be due to invalid IL or missing references)
        //IL_0018: Unknown result type (might be due to invalid IL or missing references)
        return Main.projectile[NewProjectile(spawnSource, position.X, position.Y, velocity.X, velocity.Y, type, damage, knockback, owner, ai0, ai1, ai2)];
    }

References Terraria.Main.projectile.