Z-Kart discussion

[edward850]

1. We need coders. Experienced ACS people. The mod will need to handle such things as kart physics, laps, lap times, player positions/rankings and appropriate respawn points for players who wipe out. Once the actual game mechanics are in place, the rest should be relatively easy.

I would be happy to do code support, but I can't dedicate time to it as my plate is a little full with another ZDoom related software project at the moment.

I've started programming a little demo to see how all of it can be done, and I managed to get working splitscreen:

This wouldn't work particularly well seeing as zdoom treats all input devices as the same thing, including joysticks. At best you could get 2 players, one with binary controls with the remaining 4 user inputs.

Also obviously this thing should be done for Zandronum

Or it should obviously be for ZDoom.

[GooberMan]

Oh dear lord. Zandronum? My kart script relies on things not being desynchronised (be it client/server prediction or any other kind of lag).

Of course, since this is all sprite based and purely a kart game, I probably won't have a separate car object attached to a player for this mod. So I can simplify it to some degree. But still.

[edward850]

How does your kart script work, anyway? In ZDoom multiplayer, only the player gets predicted. Not seemingly unrelated objects. Although something tells me no matter what happens, I'll need to kludge up something that allows a script of some kind to be predicted. Question is, how much control do I need to give it?

[The Zombie Killer]

More progress with splitscreen.

2 Players
3 Players
4 Players

[edward850]

I'm not sure you paid any attention to the whole "and what controls are you giving these screens?" thing.

[The Zombie Killer]

Oh don't worry, I know how I'm going to handle controls.
How people are going to manage to have 4 separate controlsets on one computer, I have no idea.

Also, weapons can be seen on camtextures in software, but not GL.
Screenshot

[Batandy]

EDIT: And I hope the intention is to just base the karts off ordinary Doom sprites. Because I *really* wouldn't be happy with ponies in the mod.

What? They don't need to be in everything.

Well there probably should be non-doom sprites, but they should all be linked to another doom mod, so yeah, no ponies

[edward850]

How people are going to manage to have 4 separate controlsets on one computer, I have no idea.

That's kind of missing the point of splitscreen, isn't it?

[The Zombie Killer]

How people are going to manage to have 4 separate controlsets on one computer, I have no idea.

That's kind of missing the point of splitscreen, isn't it?

Perhaps it is, but I guess it could still be used as a visual effect for online multiplayer.

[edward850]

That seems beyond utterly pointless. Espically if you have more then 4 players. I don't think you have entirely thought this out.

[The Zombie Killer]

I honestly didn't think it out, I simply threw it together because it seemed like a neat thing to make
Whether it has any point or not, I don't really mind

[GooberMan]

How does your kart script work, anyway?

Part one is the easy part - I override some player settings (disable inputs, change speed, etc).

Part two is the part that desynchronises - the cars are separate things that inherit the velocity of the player. If ever their positions don't match well enough, I clamp them (which results in a visible judder with the car). This generally happens whenever the player collides with something. It should also happen with any kind of lag-dependent prediction model (such as dead reckoning, which I guess is what they use in Zandronum - I haven't looked at the code but it's what Carmack used in Quake).

The sprite-based non-exitable nature of the kart game though means I can just ditch part two. The plan is to have it easily selectable for modders, but I haven't gotten that far. Need to get the basics and the infrastructure right first.

[AkumaKing]

EDIT: And I hope the intention is to just base the karts off ordinary Doom sprites. Because I *really* wouldn't be happy with ponies in the mod.

What? They don't need to be in everything.

Well there probably should be non-doom sprites, but they should all be linked to another doom mod, so yeah, no ponies

Does that mean we can have a Link-Kart since I have my Zelda mod going on? (even though said mod is a long way from completion)

Also, the only way a pony would make sense here would be this or some Pinky Pie-Demon hybrid.

[edward850]

Part one is the easy part - I override some player settings (disable inputs, change speed, etc).

Part two is the part that desynchronises - the cars are separate things that inherit the velocity of the player. If ever their positions don't match well enough, I clamp them (which results in a visible judder with the car). This generally happens whenever the player collides with something. It should also happen with any kind of lag-dependent prediction model (such as dead reckoning, which I guess is what they use in Zandronum - I haven't looked at the code but it's what Carmack used in Quake).

The sprite-based non-exitable nature of the kart game though means I can just ditch part two. The plan is to have it easily selectable for modders, but I haven't gotten that far. Need to get the basics and the infrastructure right first.

Zandro is definitely not Quake based. It's a network method stream that random functions put data into (Quakes being a frame based delta encoded stream, if I recall correctly).

For incorporating it into zdoom, either method is complicated. The script that controls the player movement isn't running when the prediction is, and the prediction cannot assume anything about the player movement, other then what it already knows. I could make it so that an individual script is called each prediction cycle that allows for additional control, but what would be tricky (without some thinking) is adding something else to that cycle (that gets properly reset in the end).

No matter what happens I'll need to make a system that handles it, however.

[GooberMan]

The good part for you at least is that I had no intention of ever overriding Doom's base physics - a fundamentally flawed idea. It's just altering the player with things like SetActorVelocity and SetActorAngle that actually matter at the end of the day. I let the normal Doom physics take care of the rest.