Sparrow needs your help! -> Particle System, Physics

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Sparrow needs your help! -> Particle System, Physics

(27 posts) (9 voices)

Started 1 year ago by Daniel
Latest reply from pixelrevision

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Daniel
Primary Feather

Hey guys,

since I received a lot of messages lately that some of you want to help me out, I think now is the time I come back to that offer.

I pondered a little about what would be the priorities of the evolution of Sparrow in the near future. I think most of you will agree -- heck, it's you who told me so! -- that the two features mentioned in the post title are most important now that all basic stuff is working stable and convenient.

So, while I am working on the API documentation and setting up other things that will make Sparrow more community-based ... it would be REALLY AWESOME if some of you could get started with those things. I know that some of you are already working on those topics.

The idea would be to have simple, ready-to-download projects available for both features, along with some nice tutorials on how to use them. These would be the first killer-features added to the Wiki, then.

Later, I will jump in and make these projects available as official Sparrow components.
However, at least the physics integration won't be added to Sparrow directly, but via a separate project. I'm not so sure about the particle system -- perhaps it's small enough to add it to the core instead.

A side effect of this is that the Sparrow code itself can't be touched. If there's a feature you need in Sparrow, we can add it to it, of course -- as long as it's useful for general purposes, not just to help out the external library.

To fit with the Sparrow philosophy, keep in mind that simplicity is everything. Rather skip some features than making the code and interface complicated and bloated. The less code there is, the less bugs can be in it. The key principle: "If in doubt, leave it out!"

Just so that nobody has wrong expectations: I may be nice guy on the forum, but Holger once called me a "Code-Nazi" because of my extreme egoism and fanaticism on detail concerning source code. So I will turn the code upside-down and show no mercy with it -- we can discuss it, but I'm the asshole that will decide what will go in and what not!

However, I have already seen that some of you are REALLY great developers, so I'm sure I will be the one who learns something, rather than the other way around!

Bottom line: what do you think of this? Does this sound like a plan? Who's interested?

I will propose some thoughts on both topics in a separate post.

Posted 1 year ago #
Daniel
Primary Feather

Physics:

I'm currently favoring ChipMunk, as it has a simpler API and is easier to integrate (as I said: simplicity is everything!). That does not mean that it's not allowed to create one component for each library. But if we set priority on one of them, it should be Chipmunk IMHO.

Particle System:

To my personal shame, I must admit that I have not used many particle systems in the past, only my own minimal implementations. I know that somebody has already ported the

http://particledesigner.71squared.com/

code to Sparrow, so that might be a start -- but only if you think it fits to Sparrow! An alternative we might look at is an API as its used in the "Flixel" Flash library.

http://flixel.org/

I have not used it - I just heard about it recently. Perhaps some of you know more about it. But perhaps some of you have worked with other particle engines, too, and have a feeling about what makes a good one.

I have created a particle class for PenguFlip that uses point sprites to render them, which is the preferred approach. I can paste the code here any time if its any help.

Posted 1 year ago #
ronaldmathies
Moderator

I'm happy that you brought it up like this and your motivations and choices are solid enough for me.

Integrating physics into Sparrow directly would, but that's my opinion, not be a good idea. There is more then one flavor out there and adding it directly into sparrow would limit some developers in their choices.

The idea of adding components which can be easily used in conjunction with Sparrow is a very good way of solving this.

I do agree on the choice for Chipmunk, although Box2D is indeed a very nice Physics engine the API is not that great. It can be quite confusing and the code that you write is quite verbose. Hence i also tried to use Chipmunk.

The API of Chipmunk is quite nice but i do think that a nice wrapper around it would follow the philosophy of Sparrow more. Like i mentioned in other topics i have started to see how it all works and how a nice wrapper can be achieved. The aim for me is to create a wrapper that has the following features:

* Ease of use
* Self explanatory API (although documentation is of course necessary)
* Flexible, if you want something that is not provided by the Wrapper you should have the ability to add it yourself.
* Evolutionary, no, only basic functionality will be supported in the beginning, my motto is "functionality on a need to have basis", so functionality will be added when it is needed and really specialized features will probably not make it.
* Integration with Sparrow where applicable.

Wow, that almost sounded like a sales talk.

So far i have a quite small wrapper for it already, it only supports some basic functionality. this is just because i am trying to figure out how it should be working and what the best practices are.

One nice addition that is possible is that you can use debug drawing, this enables you to see on the screen what the physics engine sees. (just add a SPDebugDraw to your stage).

So all in all, i will continue with the wrapper.

So about the particle engines, also i have to admit that i have no clue what engines exist and what engines are nice to work with, so i can't really say something about that.

update:

Oh, and in case it wasn't clear, i am totally interested!

Posted 1 year ago #
ahnt
Moderator

Okay,

just to lower the expectations here: Even though I would love to contribute, I never used any particle system whatsoever... so once I see the documentation I can tell you how user compatible it is, but I would do more harm then good when it comes to help from me on this end. - Oh and I am Mr. sloppy code, the "patch" Adams of the Matrix, so I guess Daniel would get a brain infact from reading my code...

And to raise the expectations: I think this is a great improvement, and if it is as easy as the rest of Sparrow this will be great.

Cheers Arend

Posted 1 year ago #
Daniel
Primary Feather

Wow, that sounds great, Ronald! If your arguments sounded like sales talk -- well, I'm sold =)

It's great that you have already made so much progress! I'm also happy that someone has worked with both frameworks -- all I know about them is by browsing through the project homepages and reading some articles, so I'm not the one to judge which one fits better to Sparrow.

So, it would be great if you could just continue with that wrapper! Take your time, experiment -- we are not in a hurry. And if anyone else is interested in that topic, perhaps you can even split up some work (if that's possible, I know that it's not in many cases) or discuss about it. Anyway: don't worry, you have not signed a contract or something, I'm just happy that somebody is working on it. If you lose interest or you find that you don't have enough time to continue, it's absolutely no problem.

Arend, thanks to you, too! ROFL - Mr. "Patch" Adams, I have to remember that one!
So it would be great if you could beta-test and comment one (or both, hehe) of the components when they are ready =)

Again, your help and commitment is very much appreciated!

From Wikipedia:

"The Sparrow is a very social bird. It is gregarious at all seasons when feeding, often forming flocks with other types of bird. It also roosts communally, its nests are usually grouped together in clumps, and it engages in a number of social activities, such as dust and water bathing, and 'social singing', in which birds call together in bushes."

Well, I'll think we can leave dust and water bathing out. As for the social singing, well ... perhaps another time!

Posted 1 year ago #
freerunnering
Moderator

This sounds great, I'd love to help.

I've never used either a physics engine or particle engine but learn quickly and would love to help.

As the particle system is simpler i'll start on that but I'd love to work on (and was planning to) a sparrow wrapper for chipmunk once I've learnt chipmunk (though by that point ronaldmathies will probably have finished it).

Posted 1 year ago #
pixelrevision
Member

I only think it requires a decision if you are trying to actually build a wrapper for the physics directly into Sparrow. Otherwise I think the big hurdle with those frameworks is getting started with them (box2d in particular with obj-c++). One solution I would propose for this is to setup a project template that at least integrates all the files and gets something like a ball bouncing on stage. This way you want box2D or chipmunk you just add the templates to your template library, and click a new "box2D sparrow project" or "chipmunk sparrow project". You get to be a code Nazi this way because really I don't think there are too many people who write code 1/4 as solid as box2D, and your core framework is left untouched.

Adding more organic simple to use physics might actually be very beneficial though. The guys over at corona did that and it really adds a lot to their framework. The way their stuff is setup you can focus on game logic and design as opposed to trying to tie together or tinker with engines which I think would be really beneficial to the folks here. The real downside they have is that once you need a feature they don't expose with lua you're up a creek (not to mention they charge 300 bucks a year or something). Creating something like this I think would also be very time consuming because getting the interface right in order to make the engines easier to use requires a lot of grace.

Do the engines you are looking at for particle emission do anything to optimize the draw calls? If not then to just dupe something like flixel might be handy for people getting started and really shouldn't be too hard to build. If we were able to figure out a few things with the render texture it could end up being really powerful, with trails and fades. This would let people create very convincing looking smoke, fire and explosions.

Posted 1 year ago #
baike
Moderator

Ronald, do you plan to do likewise for Box2D? I don't want to duplicate your work, but if you don't plan to do so, I can do one for Box2D.

Posted 1 year ago #
Daniel
Primary Feather

Malcolm, you're right - a simple first step would be to provide such a project template that just sets everything up, so that you at least don't have to worry about that set-up stuff.

Combining the particle system with the render texture is a great idea ... gosh, I see what you mean, smoke effects would work great with that. As I said, I have not reviewed many particle engines yet. Optimizing the draw call is in any case crucial for such a system - this stuff looks more awesome the more particles are on screen

Baike, thanks for your offer! Wow, I think we're soon gonna need a separate forum for the physics engine discussion alone =)

Posted 1 year ago #
pixelrevision
Member

As far as the templates I have started a new project on github to get boilerplate projects up and running:
https://github.com/pixelrevision/sparrow_xcode_templates
These are completely baseline, based off Daniel's blog post of setting up a new sparrow project.
The big issue I am trying to resolve with it is how to get xcode to pick up the header files from the libSparrow.a file (might not be possible) so that each project can just have one file replaced when new releases come out. Right now I have all the source files included in the project. If anyone has any ideas on that it would be much appreciated.
Ronald and Baike, I'd be happy to add you guys as contributors if you are github users. These xcode projects are not to hard to setup and work really well. It's pretty much like creating a normal xcode projects with a few tweaks to xml how the files are setup.

Posted 1 year ago #
ronaldmathies
Moderator

@pixelrevision, i already have a number Xcode templates available for Sparrow, they have been well received so far. They are fully functional and can be installed using a installer into XCode. I'd be happy to give them to you so you can add them to github.

It includes a file template and template for iPhone/iPad and universal projects. These are also based on the explanations of Daniel but also include enhancements (read bug fixes) of other users. (like OpenGL errors and such).

One big difference from my templates compared to your is that my templates are not reliant on a specific version of Sparrow, you only need to setup the SPARROW_SRC path and they will work.

If you are interested i can send them to you. I think templates work best when they don't contain the Sparrow source, in that way they don't need to be changed and people can make their own combinations. If a new Sparrow version is released they don't need to update the templates but just need to download Sparrow and they are ready to go.

You can find the templates online here:http://www.sodeso.nl/?page_id=1093

So far they have been downloaded for over 1190 times!

Posted 1 year ago #
Daniel
Primary Feather

Sorry, the part with the Xcode templates was my fault, I messed that up!

Malcolm mailed me about the templates, and somehow I thought I'd mentioned that you, Ronald, have already provided some of them (or maybe I just assumed he'd know about them). So I thought the 2 of you had already discussed this or were in contact.

Sorry, I hope I didn't create any frictions

I should check what I *think* I write, and what I have *really* written

Posted 1 year ago #
Daniel
Primary Feather

BTW, wow, 1190 downloads is very cool. =)

Posted 1 year ago #
ronaldmathies
Moderator

Hahaha, doesn't matter, i'd be happy to maintain them in a group then alone, otherwise i won't find any time to do other things

Posted 1 year ago #
pixelrevision
Member

Nah no frictions. I didn't realize anyone had done anything like this so I just set them up. Not like it took too long, and I mostly did it to have something up and running for folks to add in specialized stuff.

@ronald I think maybe you are right about the framework. I guess at the end of the day it is not too much to expect someone to link against it, I was just trying to simplify it. Not being able to create statically linked frameworks for iphone (at least I haven't figured out how if it's possible) is making the idea of keeping up on the frameworks within the templates kinda hard anyhow. I'd be happy to replace what I have with what you have already written, as I just whipped them together.

I still think though that having a version controlled setup with multiple contributors would greatly help out here though. This way if someone wants to setup a new template such as a box2d or chipmunk template they can just add it into the repo and not have to worry about replication. Git makes it really nice for that as then Daniel could just add the repo as a submodule in his project, this way when he is happy with the changes all sparrow users can get the newest stuff out of their pull of Sparrow.

Posted 1 year ago #
ronaldmathies
Moderator

I wouldn't mind adding the code to your repository, there should however be some control of what is being added / changed, otherwise it will become a uncontrollable jungle.

Now i notice you use GIT, i have no clue how GIT works, i have been trying just now but for some reason my commits don't really commit anything into the repository (horrible and very frustrating). So i would need to figure out, i could send you the source code by e-mail with some instructions on how it can be used. Send me a PM (Private Message) with an e-mail address so i can send you everything.

On a side note, i would prefer to use SVN, i have far more experience with SVN and it is a repository type which is more familiar with most of the developers.

Posted 1 year ago #
Daniel
Primary Feather

OK, thanks guys, I'm glad to hear that everything's fine =)

Ronald, I have the same problem as you: I'll have to learn git to use it properly - I've always used SVN (and, in my day job, Perforce) before, and there are some fundamental differences. But from what I've read so far, git is perfect for Open Source software, as it makes it extremely easy for others to share code. You can e.g. make a change to Sparrow locally on your system and then send me a "pull request", which I will see on github. Then we see online which lines were changed and can start a discussion right away, below the source code. If we agree upon the changes, I can make the necessary changes and then import the code into the main branch. That alone sounds really cool, doesn't it?

Anyway, I'm not saying that I am already able to work with it yet *g*. But I'll have a look at it in the next few weeks. When I know my way around it, and if I am then still thinking that it's worth it, the plan is to move the Sparrow source to github. At that moment, the Sparrow Wiki will already be accessible, and I'm sure Malcolm will help me write a great small tutorial on how to use it, and what one has to do to contribute code in that way.

Right, Malcolm? Right?!

Posted 1 year ago #
Matt Davies
Member

GIT is without doubt the best source versioning tool I've come across. It seems like it's really complicated but it's actually simple to use when you grok it. I would recommend you read the online book at this link: http://progit.org/book/

I use it for my home source code. Just remember to branch as much as you want - quite equivalent to perforce's changelists. And merging just works so don't be afraid to use it.

Good luck.

Posted 1 year ago #
Daniel
Primary Feather

Thanks, Cthutu! That encourages me in my plans =)

Posted 1 year ago #
monsterkodi
Member

I am looking forward to see how this develops.

I think that chipmunk is a good choice and creating a simple wrapper around it sounds also like a good idea. I think the particle system will come naturally as an addition to the physics system.

I am a relatively new git user as well and I agree that it requires some small learning phase, but in the end it is definitely worth it. There is a very nice GUI for git on mac (currently available for free since it is in public beta) which I can highly recommend:

http://www.git-tower.com/

Posted 1 year ago #
freerunnering
Moderator

Thanks just tried Git-Tower, brilliant idea. I always wondered why Github itself doesn't have a GUI uploaded?

Posted 1 year ago #
ronaldmathies
Moderator

I also tried Git-Tower, on first impression, it looks really user friendly.

Posted 1 year ago #
pixelrevision
Member

Some other git guis are:
git gui:
http://www.kernel.org/pub/software/scm/git/docs/git-gui.html which comes with git (it's a little linuxy for me)

gity:
http://codeendeavor.com/

and gitx:
http://gitx.frim.nl/

Posted 1 year ago #
Daniel
Primary Feather

Talking about git:

https://github.com/PrimaryFeather/Sparrow-Framework

Tadaaaaa!

The project contains 2 branches: master and development. The master branch will always contain the content up to the latest release. Development will then continue on the development branch. When the next release is due and all bugs are fixed, that branch will be merged with the master branch. Furthermore, each release is marked with a tag.

It would be great if those of you experienced with git and/or github could have a look at it, just to check if I didn't make any fundamental (embarrassing) mistake. If everything is fine, I will announce the change on the Sparrow website.

Thanks in advance!!

Posted 1 year ago #
enbr
Moderator

Awesome, thanks Daniel.
Will people be able to contribute to the development branch through this?

Posted 1 year ago #
Daniel
Primary Feather

Yes, but not directly (the branch is read-only), but by sending patches or pull-requests. Pull requests are handled in a very cool way by github; one can see the changes online and discuss them directly on the website.

As I am just learning to use git ATM, I do not have much experience on that stuff yet, though.

But the next step on my todo-list is the wiki, and I will add a description on how to do that when it's ready.

Posted 1 year ago #
pixelrevision
Member

Awesome! Just grabbed it.
@enbr take a look at:
http://help.github.com/pull-requests/
Particularly the fork and pull model.

Posted 1 year ago #

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