Add offhand grapple

[rdntcntrl]

Add option to be able to use the grappling hook while holding a weapon at the same time.

[Parker1200]

I implemented this feature in my fork. This can be useful when doing it in the main branch here. I'm new to GitHub and have no C programming experience, so my code probably needs to be improved. However, everything seems to be working as intended.

[oitzujoey]

g_grappleSpeed isn't predicted client-side. In order to set pm->grapplePullSpeed client side, you will need to mark g_grappleSpeed as CVAR_SERVERINFO and set pm.pmove_grapplePullSpeed (which doesn't exist yet). If you want a reference, g_movement serves a similar function.
We will eventually run out of space in the server string, so Rdnt will have to okay it. It's not hard to overflow it.

[Parker1200]

OK, I have made a new commit. I can only vaguely understand how this works in practice and whether I did it correctly. I don't know if that did the trick or if I missed the point completely after all. I also assumed you mentioned g_grappleSpeed by mistake. If that was intentional, I only tried to deal with g_grapplePullSpeed prediction.
EDIT: I can confirm that the client side prediction works. I injected on the client side some crazy value for grapplePullSpeed like -990000 which broke the prediction. I assume that when the value is set correctly from the server info, it works fine. I opened the issues tab on my fork page in case there are more problems. Thanks and let me know if this should be merged here. If the code needs to be reworked then I hope I helped somehow.

[rdntcntrl]

Very nice! I've made a new branch "offhand_grapple" with some additional changes.I made offhand grapple dependent on having the grappling hook item. This will cover more possible configurations: - `g_grapple 1` + `g_offhandGrapple 1` => you spawn with offhand grapple - `g_grapple 0` + `g_offhandGrapple 1` => you have offhand grapple once you pick it up - etc The hook "missile" is not currently locally predicted, so no need to communicate `g_grappleSpeed` via serverinfo (although this might be needed at some point).`g_grapplePullSpeed` looks good. I think the firing itself should probably be done via an event similar to `EV_FIRE_WEAPON` so it can be locally predicted (notice right now the sounds don't play properly). I haven't looked into the details yet though, could be a messy change. Also, we'll need to add some sort of indication that offhand grapple is on (`cg_drawGun` is the obvious answer).

[Parker1200]

Thanks, the new branch looks great.
I haven't touched the code in weeks as I am busy with other things. By adding the EV_OFFHAND_GRAPPLE event, I wanted to make it eventually work similar to how EV_FIRE_WEAPON works, just as you suggest it could be done. I guess it can solve a lot of problems. I think adding a prediction for the grapple would be the first step. For that, I would have to better understand Open Arena's source code (and C), so the code was kind of abandoned. Actually, I wanted to roll back EV_OFFHAND_GRAPPLE myself as it was only used for messy shader initialization so far, but you made better changes than I could at this stage without having to register the grappling hook item at the start of each game.