sunnywiz – Page 12 – A Geeky Gulati

dotNetMud: Its Alive! (on azure)

The link: http://dotnetmud.azurewebsites.net/

From there you can either get into the old-fashioned text-and-chat mud:

(Valid commands are who, look, shout, say, and east and west)

Or you can get into the space-mud side of things:

(Valid controls are W for thrust, A and D for rotate)

Neither of these are really interesting until you have more than one client (browser, tab) logged in. In the case of the latter, perhaps from different computers, with different network speeds.

Corresponding source code: approximately here (as of these screenshots): https://github.com/sunnywiz/dotnetmud2015/tree/blog20160220

Where to go from here?

I could try to make the space game more fun – adding missiles and lasers. More realistic game. You can’t have a space game without combat.. can you?

I could try to make the space game more single-player interesting – adding gravity, multiple planets. (your mission: try to get into orbit around a planet). This lends itself to “more realistic server side computational load”.

I could try to make the space game more efficient – optimizing network traffic (right now, VERY large messages).

I could try to make both clients work better – by having “session” be the unifying factor, and the text game launches the space game, both in the context of the same player object, somehow. This would probably involve hooking up to a database for persistence of user information as well. This is complicated… this is probably where I should go if I’m focusing on the “sample game” side of things.

I could try to make space more interesting – by voronoi’ing it, so that it can have 10000 or more objects, but its very easy to find the objects that are within, say, 100000 units of you. So that I can do hyperdrive between star systems that you can drop out of and be in the middle of nowhere. Also complicated.. probably comes after multiple planets.

I could try to stress test it – get a bunch of computers attached to it, see how it performs on the azure side. I have it running on a Free web-node at the moment, and its surprisingly happy – 1.9% CPU.

StoneHearth (Alpha 14)

I have been playing a very cute game: StoneHearth. I paid $24 for it on Steam, its in Very Early stages, and I don’t regret the purchase.

However, be aware that, as it stands right now, its not very challenging once you learn how to stay alive.

I put together one farmer (prevent starvation) and one footman (prevent death by first attacker), and then mostly left the game alone after that, and … everybody lived. Overnight. I’m sure they would have died of cold eventually as the seasons changed, if that were implemented. But as it is, the game settles into a sustainable state, doesn’t devolve into chaos.

Comparatively, I left City : Skylines running overnight and it did descend into chaos. How? by the one simple rule of “no-auto-bulldoze-condemned.” It’s the one thing that left unmonitored, will destabilize everything.

Also, if you do silly things like dig tunnels to then fill with water, some algorithms crash (you can see some of that above) and stuff and things generally go haywire and people stop picking up stuff etc. Performance and Bugs.

The concept, though, is solid. I love watching the little hearthlings do their little lives.. I guess this is what the Sims was like.

The build tree took a little getting used to. I couldn’t find a nice graphic on the web, so I tried making one in LucidCharts:

However, LucidCharts (Pro) does not appear to have an auto-re-flow option, and if I started getting the level of detail I wanted .. it would not have worked.

What other options do I have? A little google searching found: http://bl.ocks.org/d3noob/5141528, So I downloaded that code, and plugged in my own CSV file. But ran into cross-origin problems.

So then I went with http://jsfiddle.net/skysigal/k3kdeu9L/ which I forked into my own .. http://jsfiddle.net/roLmyovw/2 :

Which is just not quite pretty. Not as pretty as this kitten, anyway:

Which is my Princess Fifi Toupee. She kept trying to step on the keyboard as I wrote this post. https://www.instagram.com/p/BB27Zh1Fvko/?taken-by=mollymcmahan

So, I think I’m giving up on this game for now. I played it for 8-9 hours. Maybe not the best return, but I suspect I’ll play it again in the future.

dotnetmud: Hitting a wall on clients, hubs, and games

Till now, I’ve had this pretty simple layout:

The browser fires up a signal/R client, which connects to a signal/R server, which talks to a driver, which talks to a game-specific engine.

One signal/R client maps to a user in the game somewhere.

This Situation is not Covered:

You are standing in a spaceport

You see:

a ship

>> board ship

You are inside the ship. you can ‘launch’ to launch the ship.

>> launch

At this point, something happens that tells the client “hey, start this other client up” – possibly in a new tab. Maybe it leaves the current tab in place. The new client connects up to its own hub, with its own mudlib, and does its own kinds of commands. The user can then fly the ship around in space. The space stuff doesn’t know that the ship is also a “mudlib” object.

This could also be used with Shop Transactions, or a Game of Uno, or whatever – custom client for custom situation, in the same user’s session.

What this Means

a) I need a different sort of Auth mechanism to bind the user to an Identity. I think I’ll probably go ahead and use the stock website’s authentication methods to get myself an actual UserIdentity; I don’t know if that would flow down into any signal/R client or not.

b) Every user can have MULTIPLE clients going on at any point in time.

This is making my head hurt. I’ll let it percolate. For now, no cross-jumping between clients.

HOWEVER, I do want to move the <T> that I currently have on the Driver so that the Driver stands alone, and the Signal/R Hub is the one that knows about the mudlib GameSpecific.

(dotnetmud) spacegame: accelerating to a planet

I shook some dust off some old braincells, and re-remembered some algebra.

My quandry, as hinted by previous post: GIven that I’m 42000 units away from the planet, and I have a max acceleration of 100 units/(sec^2), how much do I accelerate in the direction of the planet?

Some googling finds this: https://van.physics.illinois.edu/qa/listing.php?id=116

d = vt + (1/2)at²

I know my distance, 42000. And I know my a, 100. What I need to calculate is v. But not the one in the equation – that’s starting velocity.

Reverse it. At the planet, starting at v=0, what’s my final velocity when I get to distance d?

The velocity is v = at. So if I can solve for t, then I can plug that in.

d = (1/2) att

tt = 2d/a

t = Math.sqrt(2*d/a)

v = a * Math.sqrt(2*d/a).

Check the numbers in excel. I set it up like this:

And plug in the formula to see how well it calculates speed:

The drift is due to the coarse 1 second time interval on the calculations, I’m pretty sure.

So, the answer is, if I’m 42000 u away from the planet, and I can thrust at 100 u/s^2, I want to be going 100 * Math.Sqrt(2*42000/100) = 2895 units/sec in the direction of the planet.

If I’m not going this speed, I need to boost in the direction of the planet.
If I’m going faster than this speed, I need to boost in the other direction.

To make up for inaccuracies, I’ll set the target velocity to match, say, 90% of my actual available acceleration.

I’m not accounting for my initial velocity at all, even if its not in the right direction. The point is, at any point in space I can caluate what my velocity should be, and what direction it should be in, for the fastest approach to the planet. Whatever I’m doing, change to match that. It should be a nice curve, followed by some nice acceleration, followed by a turnaround, and then some deceleration with some waggles.

Looking forward to implementing it. No time tonight, so I just blogged about my resurrection of Physics 101 instead. Super-excited.

DotNetMud: SpaceGame: Autopilot

After an aborted run at Rares Trading in Elite Dangerous (idea: pick up rares, go to Fehu, sell them, and then pick up missions there. Problem: takes many hours to get enough worth selling), I took a look at writing an autopilot in my javascript space game (the part that is not yet Mud-like, but I intend for it to be).

Nice: Javascript has a Math.atan2(y,x) which _possibly_ avoids the x=0 problem that normal Math.atan() solutions do. (arctangent gets you the angle to something so you know where to point the ship).

However, my code doesn’t work. My ship very often points AWAY from the target, and applies FULL THRUST FOREVER. This is NOT how you go somewhere.

There’s another aspect – I’m simulating “keyboard control”, ie, IsThrusting, IsLeft, IsRight. For the ship to feel responsive when playing the game, need to have good numbers for these. But with autopilot, there’s a lot of jigger (LRLRLRLR) because it continually overshoots its target.

So, here’s what I have to do for the relatively final solution:

Set up the ship so that there’s a finer gradient of control.
- What I’ve seen other games do is, the longer you have it pressed, the more thrust you get, up to max.
  - This means I need to swap out my current keyboard handler (keyup, keydown) to change to a dictionary of “when was it pressed”, so that I can calculate how long its been held.
- Or, I could go with W = 12.5% thrust, Ctrl-W = 25%, shift-W= 50%, and ctrl/shift = 100%. Almost 8 stops. More instantaneous full thrust available.
  - I want to avoid something where the autopilot can take a shortcut that’s not really available to a player. So if I did the slow build up, I’d have to have the autopilot also do a slow build up.
Change how I do the maths for the autopilot. Inputs to autopilot: Who to go to, and what distance to orbit them at when we get there.
- I see a few major layers.
- First one is “close the distance”. This would use the calculation of … http://physics.info/motion-equations/ … ouch, my brain hurts. Basically, I need to find a solution for:
  - If I start at the orbit distance, and accelerate away at 75% thrust, what velocity am I at when I get to my current distance away? Reverse that. That’s the velocity towards the object that I want. Call that V1. I want it to shut off as I get close to the destination so that orbital stuff can kick in.
- Second one is orbital force. Skip this if I’m more than 2x the desired distance.
  - Figure out if I’m going clockwise or counter clockwise from the destination. OR, just assume one direction for now. clockwise.
  - Figure out the vector I need to be in a perfect circular orbit around the object at the desired distance. Magnitude is known (previous post on orbital mechanics has link to the article), and Direction is 90 degrees from where the destination is.
  - That’s my desired vector V2.
- Combine V1 and V2. This is my desired vector V3
- Look at my current vector V4 and figure out the change that needs to happen V5 = V3-V4.
  - Do a left/right thrust as needed to point me at that vector (do a smoothing function here).
  - if I’m pointing in relatively the right direction, do a thrust along that vector (do a smoothing function here).

This could be really fun.

Image: wikipedia

When Maths goes right

I found out I had been doing gravity wrong.

This is what I was getting:

There seemed to be gravity, but it was messy.

I had been using the good old (G*m1*m2)/(r^2) equation. However, in an effort to be smart, I calculated the (x2-x1) * (y2-y1) to be the (r^2) value..

WHICH IS TRUE.

And when you apply that force to an object of mass m1, the m1 disappears (F=ma; a=F/m) and you get the acceleration, the pull of gravity.

But, the kicker is, I then have to scale the normal vector out by that. And the normal vector is… just the x component .. is .. (x2-x1)/r.

When you do the whole thing, the acceleration felt is proportional to 1/r^3, not r^2.

So I did that. And I pulled out the gravitational constant, G, to use elsewhere (turns out you can calculate orbital velocities and periods as well).

The result:

No matter where you start, no matter your initial velocity and direction (within reason), you get a nice orbit.

What’s more, I could use the maths where “velocity at distance r” can be calculated, as well as “radians per unit time” can be calculated, for a circular orbit.

This means, I could write an autopilot to get you in a circular orbit around a star or planet at a particular distance pretty easily. I think.

However, I also found out that due to gravitational effects of planets, it was very easy to get swept into the sun.. and then gravitationally flung out of the solar system.

So, I changed it when you get within the radius of a planet, gravity is about constant – like it would be at the surface. “Airbrakes”, as it were.

THIS HAS PROMISE! I spent probably an half hour flying around in this simulation, gravity made it so interesting.

source: https://github.com/sunnywiz/dotnetmud2015/blob/e5db82581382e43a721f0abc4a5c45710ed7fee4/canvasTest/solarSystemFlight.html

it needs one image from the same directory. Otherwise, just run that file.

dotnetmud: inheritance and awareness and IoC

I’m running around in circles, so I thought I should try to draw it out. Click to zoom in if not legible; text below explaining.

All the words are driving me nuts. So I added A,B,C,D to the diagram above.

A = the layer that talks network transport stuff, like Signal/R.
B = the layer of the game that cares about booting up, shutting down, who is logged into the game, loading and unloading of realms.

This stuff should NOT be directly available to in-game objects to mess with!

C = subset of B. This is the stuff that should be available to in-game objects. It’s the O/S of the game, as it were.
D = game code. In the case of wizard-coded realms, probably gets scanned to make sure it has no assembly references, and in days of old might have run under CAS.

I’m not actually going to secure it, just want to make sure its probably securable.

Requirements:

A should not know about all the stuff in B; just bare minimums to talk network occurences to.
B should definitely not know about the specifics of A. In fact, I’d say B is an assembly that HAS NO REFERENCE to Signal/R.
D should not know about B. I’d go with: D can ONLY have an assembly reference to C, and NOTHING else; if something is to be made available to code in D, it must be added to C as a pass-through.
B & C can know all about each other.

Singletons vs Static vs ..

Lets call “C” the driver layer. Ie, IDriver.FindObjectByName() would be an example.

For all the code in the Mudlib, right now, it does stuff like Driver.Instance.FindObjectByName().

It might be better to use IoC and take an IDriver in the constructor, and then call _driver.FindObjectByName(). HOWEVER, then I get into things like “Can I have IoC limit which objects can be created”, and “I want to make sure as the objects are created that I can keep track of realms and stuff like that”, and all of a sudden IoC is too nice a tool to use. I’m sure it could be used with guards on it, but .. leave that to somebody else, I have no joy in solving that.

So then I could go with how many libraries get a hold of things – (static class DotNetMud.XXX).Driver. Always gets you the same one every time.

But if I’m doing that, why not just have a static class, Driver.FIndObjectByName()? No, I don’t want to do this, because I MIGHT want people to be able to unit test their mudlib objects, and I want the driver to at least be an IDriver so it can be mocked somehow.

So, I think where its going is, I’ll have a poor man’s IoC. DotNetMud.Global.Driver gets you the driver.

Who References Whom? How to deal with the Inverse?

D references C for sure.

A references and feeds B, including telling it how to talk back to A (via Lambda’s)

B is configured to know how to get to D.

C, when asked, can create objects from D. but it only knows D through configuration.

C needs access to stuff in B

B doesn’t need much from C/D, other than the interactives list, I think.

So there’s another guy, @, who:

reads configuration to determine

Who is D
Who is D.GameSpecifics

Creates or Gets Singleton of B
Creates or Gets Singleton of C
Informs B of C or C or B or whatever. Not sure about this part yet. Probably they each know each other’s interface.
Tells C enough stuff about D so that it can create objects from D on demand.
Tells A about B

I would say creates A, but … SignalR does its own creation. So really more like when A is created, self-registers the context somewhere and triggers something so that A can talk to B.

Right now its all in one assembly.

This stuff is TOUGH.

And it gets tougher with code loaded on the fly. I don’t think I’m going to deal with that yet.

No wonder when I open up the project, this stuff isn’t flowing well. Smile

How to get it there

I think I should probably get everything living in the same assembly at first, except under a web server rather than a console app.

Then, get the singleton-reference stuff in place. DotNetMud.Global.xxx. Change all references to do that.

Then, peel out the MudLib to its own thing. It still references all of B/C combined.

Then, peel out C to its own thing.

Then, peel out B to its own thing, separate from A.

This is a several-hour project, I fear.

Offline Briefcase Sneaker Sync

Problem

I have 1.6TB of “stuff”, that I want to keep synced between home and off-site.

I’ve tried several ways of online syncing – Crashplan, BtSync, Rsync, etc – and it always breaks down somehow. I’m tired of relying on the internet to get it done.

I travel back and forth between these locations all the time. How about a sneaker-sync?

Two desktop computers, with 1.6 TB of stuff
1 128G USB drive to store the Deltas
A program to run at either site, that can figure out what to put on the USB drive, to bring the two repositories in sync with each other.

Solution Proposal

Here’s my thoughts on what it would take. It can be given a pretty UI later.

USB flash drive of arbitrary size
SneakerSync.exe, .config
- Relative location to path where files are kept.
- maximum size of the USB flash drive to use.
- % to keep for deleted files
- Repository/db of tracking stuff.

Target computer #1:

F:\Share <—has the tons of stuff

Target computer #2:

\\NetworkLocation\Share <—also has the tons of stuff. To be kept in sync.

To make things simpler, I’m just going to call this the “share”.

Command line Usage:

sneakersync.exe f:\share when at computer 1
sneakersync.exe \\networklocation\share when at computer 2

What it does:

Scans to see what the latest/greatest are at a given computer.
Determines files that need to be synced to other sites
Determines files that are out of date with reference to other sites
Updates local files if it knows what it has on the stick is fresher
Grabs any files that DEFINITELY need syncing on some other computer somewhere else
Backfills other interesting files if there’s space available. Probably in most-recently-updated order.
doesn’t delete anything – saves copies on usb stick, rotating buffer.

Future Autorun usage:

Autoruns, looks around for file systems it can update that it knows about, does the update.

To pull this off, what would it need

Define: “Logical Share” = the concept of the file system, regardless of how many machines it is spread across. Think of it as “the dropbox”, for example, when using dropbox.

Define “Physical share” = the files on a disk on a computer.

We would need to track:

Logical file system contents, plus which computer has the “most recent” or authoritative version of a file.
physical file system contents, as best known, for all physical file systems.
- With each physical file system file, the determination that it needs to be updated (ie, its stale, logical has newer)
What’s in the briefcase for transfer
What’s in the briefcase in the trash can.

Side Effects / Interesting conditions.

There will be conflicts where the file has been modified on both computers. I’d say, alert the user, take the most recent one, and stick both copies of files into the trash can.

If you somehow loose all physical instances of a share, you should have the most recent N files in your briefcase. Hopefully that’s enough to get you back to a backup.

When will I write this code

Maybe never. Its been in my head for a few years; I have some other stuff I’m working on right now. Maybe somebody else is interested in writing this and monetizing it? Smile

Or even better, maybe somebody else has already written this.

dotnetmud: space: gravity

playing with Html5 Canvas – doing a control loop with thrusters (blue) and rotation control — adding in two fixed points which have gravity.

I’m using m/(r^2) here .. its not quite right, as the two objects are not orbiting each other. I can’t get it to orbit nicely Smile

I turned off the “clear canvas” bit so that the paths could be seen.

The red bits are drawing of the force lines due to gravity calculations.

dotnetmud: where to go next

As of https://github.com/sunnywiz/dotnetmud2015/tree/blog20160110, I have the following things working:

User logs in and provides a name.
User can move back and forth between two rooms (room directions are hooked up)
User can ‘look’ to see what’s in the room. They will see other users there if they are there.
User can ‘say’ something in a room
User can ‘who’ to see who all are logged in
User can ‘shout’ to send a message to everybody regardless of which room they are in.

I am now at a crossroads. There are many directions I can go. I’m crossing things out as I decide that they are not the priority:

~~1. Develop the “mud” as a communication mud more:~~

~~Continue with all the communication stuff – tell, emote.~~
~~Add aliases for commands, like ‘e’ for east and ‘ for say and : for emote~~
~~Fix the say and shout so that the original command line is available rather than string[] arg (ie, I’m loosing whitespace)~~
~~add the Id() system so that objects can respond to nouns, so that ‘look <personname>’ works~~
~~Add last activity timestamp to user so that can detect idle time and show that in the who list~~
~~Show which room the user is in, in the who-list.~~

2. Add in realms

~~Users can.. hook up a pointer to a git url ? to point at their realm code.~~
~~Mud sucks the code down, compiles it, loads/unloads appdomains, etc.~~
Might have some hidden difficulties here around MarshalByRefObj type stuff.
Maybe there’s an intermediate stopping point here – where I appdomain-unload-load the rooms that the users use as Lobby.

~~3. HTML/Pretty the mud~~

~~Right now the text being displayed to the user is all mono-spaced, no HTML allowed.~~
~~I could change that so that HTML was allowed.~~
~~As you enter a room, a picture of the room shows up.~~
~~People get gravatar icons next to their names.~~
~~Add fun emoticons and stuff.~~
~~Who is shown in a table.~~

4. Clean up referencing

Move “driver” stuff into its own assembly. Gets a DriverObject. This does ObjectID and TypeURI stuff, and knows about IInteractive, and talks to the Signal/R Hub, but that’s about it.
Move “mudlib” stuff into its own assembly. Gets its own MudLibObject which inherits from DriverObject.
clean up who references who, who finds who. Use the .config file more to provide the links going in the wrong direction.
Move some stuff (like “inventory”, and “moveObject”) into the mudlib, rather than at the driver level. These are text-based game things, and would not be (as) applicable for a Space-2D game.
Wrestle more with “should I directly map hub commands to the mudlib”, or make all communication with the hub generic. Latter is more painful, but would work with more gametypes without changing the driver.

4.5 Deploy as a website to Azure

RIght now, it’s a console app. Convert it to be a full website, which runs the hub in the background

I don’t know how Azure’s “free hosting” will work with a signal/r hub which wants to stay instantiated. May have to put this on a paid plan
Luckily my work gives me an MSDN account now, and there’s free azure money there that’s use is or loose it.
Maybe put some stuff in like a welcome page.
Maybe do some integration with your identity as you log in coming from the MVC side rather than entirely in the mud.

5. Deal with Polling

For this, I’ll change the client so that it has panels:

One for “where you are”
One for “what you see here”
(future) One for your inventory
And then an updates window where “stuff” happens.

The poll cycle will be, once every X, if something has changed, refresh the where-you-are and what-you-see-here windows.
Additionally, for each user, give them a “how long they have been idle” thing on their short description

The poll should detect these changes and feed them down correctly.

If I get the above stuff done – definitely 4 and 5 – I think I’ll be in a place where I can start working on my 2D space game.

One day at a time, one session at a time.