Game Development

Gajet

20:03

@C++folks

1131

Q: What is the name of this operator: "-->"?

Moderator Note: Please think carefully before providing another answer to this question. If your answer duplicates an existing answer, it will very likely be removed. After reading "Hidden Features and Dark Corners of C++/STL" on comp.lang.c++.moderated, I was completely surprised that ...

Paul Manta

@Gajet Old! :P

Gajet

C++ always seems to be surprising me with new methods of development...

@PaulManta new for me

TreDubZedd

std::cout << x-- > 0 ? "x was greater than 1" : "x was less than 2";

Paul Manta

@TreDubZedd I suspect that's just going to print the value of x-- > 0.

Gajet

@TreDubZedd compile error

TreDubZedd

20:06

See also: the ++> and -- <= operators

Paul Manta

It's going to be interpreted as (std::cout << x-- > 0) ? "x was greater than 1" : "x was less than 2";, I think.

TreDubZedd

Pseudo-code. My apologies

Gajet

I've just had an operator precedence bug that got me for two days

if (visible.mParts.back().mPoints.size() == 1 && visible.type & (OT_linestringcollection | OT_polygoncollection) != 0)

@TreDubZedd @PaulManta can you spot it?

Paul Manta

@Gajet I'm looking at it. :)

TreDubZedd

I assume (without looking it up) that visible.type & (OT_linestringcollection | OT_polygoncollection) is not what you meant

Gajet

20:11

just a little hint, that if statement always evaluates as false!

TreDubZedd

or rather, is what you meant...but that visible.type is being compared to zero

so (OT_linestringcollection | OT_polygoncollection) != 0 is evaluated first

Gajet

exactly, and visible.type always contains some flags at it's second byte so it is never 1

now that I'm thinking it's pretty odd it always evaluated as false, sone there are some enums in that code which have 1 at their first bit.

but anyway I just keep banging my head against the wall when I found out what the problem was...

TreDubZedd

I was under the impression that anything non-zero evaluates to true. Is that not the case?

Gajet

that's true, but true is always evaluated as 1 when you cast to int

TreDubZedd

ah, so it's always visible.type & 1

Gajet

20:16

exactly, and I guess the first part was always false for all the enums which had true as their first bit

Dave

dont worry i'm still here :P

TreDubZedd

Looking at the operator precedence list, now....I find it odd that bitwise shifts are not at the same level of precedence as multiplication and division.

Dave

i have node installed with latest version :D

tylerrrr07

@Dave woot woot!

Gajet

there should be something wrong with the man who designed that list, none of bitwise operators are where you assume them to be.

MarkR

20:21

I have not quite worked out what "node" is really useful for... it is based on the Chrome JS engine, which is pretty efficient, on the other hand it's really a poor development environment... poor libs and lack of useful debugging, tool support etc

Gajet

I mean who does a bitwise and between a value and a boolean(result of comparison)

thelinuxlich

try vert.x

vertx.io

Dave

no idea how i use it tho hehe

MarkR

@Dave it is quite interesting, JS is not a really terrible language

Dave

yeh my host installed it but no idea if its running or wat etc

MarkR

20:28

Node does not have an standard web server system, you have to run an instance

Dave

i should mention im a complete noob when it comes to servers

MarkR

But of course you can use it for other protocols, such as game servers, which is quite interesting

Gajet

good night everyone

Dave

good night @Gajet

Gajet

@WilliamMindWorXMariager you didn't show up tonight either!

it's not my fault you are not here when I am...

MarkR

20:29

But Node is quite a lot like Twisted, which has been around a lot longer and originally intended to write game servers

Dave

i only need it for some simple js functions in the backend

MarkR

Maybe that's not the best way of doing it then

Dave

i cant use js on client

people will cheat

MarkR

You say "some simple functions"

Dave

path finders

MarkR

20:31

But surely it would be your entire game logic...

Dave

yeh :P i considered them simple i dunno why i used that word xD

things like path finders are back end to prevent people walking faster or places they shouldnt

MarkR

What did the rest of your back-end use, and why would you not use that?

Dave

well i use ajax to call php scripts to get data from my database using mysql in php files

but i wanted to use js for my pathfinder as i already have it made in javascript

remaking it in php is a pain in the butt

MarkR

I suppose you want some kind of service which you can ask "is point b reachable from point a in time t?"

So you could code that into a node.js server of some kind, then have your PHP talk to it

Dave

i was guna just send start position and make it find the path

then send the path it found back

to client JS which would use it to draw the npc's movement

Dave

21:00

i killed chat :(

Damir

@Dave Send position to the server, find path, send path to client?

Is that your idea?

Dave

yup

users will cheat the path finder if i leave it client side

Damir

Like @MarkR said, you can use node.js

Dave

i have it installed but clueless with what im doing with it

Damir

Well, how do you want to communicate with it?

Directly to node.js server or through your PHP server?

Dave

21:05

i dont know any thing about servers which is better?

Damir

Whichever is easier for you.

You could switch to node.js and have both the server and client written in JS

But then you'd have to rewrite those PHP scripts for javascript.

Dave

i've really got no idea what you're talking about - servers is something i have zero knowledge on except how to make a cron + upload scripts :P

my host had to install node.js for me cos i had no idea

Damir

ah

Dave

:(

i dont get how people learn this

Damir

You're making a multiplayer game, yet you have no idea how servers work?

Dave

21:12

ive never had to do this kinda stuff with a server before

ive hosted websites etc but none of that involves installing some kind of library like node.js

or having to worry about which server to use for communicate etc

Damir

Well, you'll be coding your own server now.

Dave

=/

Damir

The choice was about languages to use.

But why do you need a server?

What should it do?

For your game

Dave

well i use ajax to php scripts to grab data from my database. but i need things like game logic server side to prevent people editing the code in their browser

and as i already have some of the scripts in js done it was suggested i use node.js

i just went by what people suggested :P

Damir

Yes, node.js is good.

If you can rewrite your database scripts for node.js, you won't need PHP at all.

Have you managed to communicate between your game and node.js?

Dave

21:18

"database" scripts?

my database interaction is just mysql in php files at the moment

if i can rid of php that be good

no i aint worked out how to get them communicating

i basically have the latest version installed on my server n thats it so far.

Damir

Browser game, right?

Dave

yup

Damir

You should use websockets, then.

Take a look at socket.io

Dave

instead of node?

Damir

No, it is an extension for node

socket.io

Dave

21:21

i thought socket io was for live stuff

like say a chat room

Damir

Shouldn't your game be live as well?

Dave

well for things like path finder - no. i was going to do a "send position" > "find path" > "send back result"

v.similiar to ajax

requests

Damir

I'm not really sure I understand your definition of live.

It doesn't have to be a two-way transmission with socket.io

If that's what's bothering you.

Dave

well once it sends position n gets the path returned it doesnt need to ask it to calculate again unless an event occurs

Damir

That depends on how you code your server, i.e. whether your going to check if the start/target position has changed.

In general

To do something like "send position" > "find path" > "send back result"

Dave

21:29

it will change but only on events by the user so i know when it changes rather needing to check if it changes at random

periodically checking wont be needed for it like u would a chat room normally

Damir

You send a packet (a message) from the client with position via server's listening channel
Server does its stuff
Server sends result in a new packet via client's listening channel.

@Dave Yes, that depends on your implementation

Dave

the game is based on placing buildings/paths

not some one walking on a map at free will like a rpg

is it worth keeping a channel open 24/7 if its event driven instead of opening and closing when an event occurs

tigrou

I just spent two hours answering a question and just realize the guy as only one question in profile and never connected since months ....

Damir

@tigrou Don't feel bad, man. You did a good deed :)

@Dave The channels are open while the client is connected.

tigrou

I

Damir

21:34

I do not remember the details, but there shouldn't be much traffic while idling

Dave

it seems pointless to leave it open if no data is being sent

Damir

But I do not think that is something you should concern yourself with, right now

Try it out. Get your client-server communication working.

Dave

im trying but i dont get it :P

Damir

Try examples first

Then back to your game

Is there anything specific your not getting?

Dave

ill check the example out first

tigrou

21:38

One question about gamedev stack : is there any topic talking about personal game projects (non commercial) (just like there is a topic about good programming blogs) i search but found nothing and hesitate to create new question (feel out of scope). I will be interested to see what some of you have work on.

Damir

@tigrou I think those kinds of threads are frowned upon.

user4704

There isn't, and it wouldn't be on-topic

Damir

Hang around here

user4704

Indeed; watching this chat is a better way to get current information on things people are working on, because people will discuss their projects frequently

Dave

@Damir this part i don't get

To run the server, put the code into a file example.js and execute it with the node program:

i made the file

but how i run the node program =/

Damir

21:45

Do you have node on your computer?

Dave

my computer ?

or my server

Damir

On your own.

It might be easier to understand if you have full access

Dave

i have open node.exe

on windows 7 which is showing a console

is that what it means by node program

Damir

Yes, and you need to execute your script with it.

Dave

yeh look at their example: nodejs.org

on front page it don't say how u tell it where the script is on my server

Damir

21:49

Just a moment

Let me see how to do that on Windows

You could run node.exe path\to\script.js

From cmd

Dave

so just type the domain to it =/

Damir

Local path

Dave

local path from my computer ?

how is it even connecting to my server

Damir

Let's use your computer as a server for now

Ok?

Dave

ok hold on then let me put the js file on my desktop

@Damir i.imgur.com/X2BKZ.jpg

not much happened

im guessing i did it wrong ?

Damir

21:57

Try running node.exe C:\DAve\...\script.js from cmd

Dave

how do i run the node from cmd?

Damir

A moment

"To run Node, open a Command Prompt and type node. "

Open cmd and try this

Dave

ok

it says cmd.exe - node

in the window header

guess that did something :P

is there no private messaging on gamedev

Damir

Nope, but we can open a separate room

JMRboosties

22:20

this is an interesting convo for me to read

im going to move into networking for my game shortly

Damir

@JMRboosties We're talking more about setting up node.js now

Feel free to drop by if you're interested

JMRboosties

@Damir oh, ok

Damir

22:47

@Dave nodejs.org/api/appendix_1.html

Dave

thanks :)

William 'MindWorX' Mariager

23:01

@Gajet I have my computer on a 10/10 mbit connection, but I'm more than willing to let you use it for testing. :)

Damir

@WilliamMindWorXMariager Are you a magickan?

William 'MindWorX' Mariager

@Damir I only delve in the blackest of black magic, so that would be a yes.

Dave

23:41

just been asking on the JS chat n they said i shldnt use node @Damir

Damir

Well, I haven't used anything else for JS, so they might be right

What did they say?

Dave

well they said if the calculation takes some time itll cause a backlog

so if it takes 200ms to calculate then everything else has to wait

Damir

Hmmm

I thought node was capable of multithreading.

Dave

they said to just use xhr method

tylerrrr07

I think it was @thelinuxlich who mentioned vertx.io

On their site: Just spin up more instances:

vertx run server.js -instances 32

Vert.x will do the magic to ensure the requests are distributed amongst the instances:

Dave

23:48

you referring to my issue @tylerrrr07?

Damir

@tylerrrr07 This looks nice

tylerrrr07

@Dave yes

I know nothing about it but I glanced at their website when it was mentioned

I remembered that so I thought I would pull it up since it sounded relevant - though maybe its not? I don't know.

Dave

oh lol this is all new to me so im a bit AHHH at the moment

i knew i'd dread the network server stuff when the time came

@Gajet you about?

Transcript for