Game Haxe

3 Years On

Wow, has it really been 3 years? 2009 was an interesting year – I guess the big ticket items were haxe for the iPhone and getting hxcpp into the standard distribution for haxe. I am very satisfied with these achievements, however there is still quite a bit of polish to add – especially in terms of ease-of-use. I also started some other projects – fastcgi for haxe, and “waxe“, the wx/haxe interface, as well as continuing with neash and nme development. One of the big changes for hxcpp, although not visible, was using an internal garbage collector which has improved performance and reduced the compile dependence on a library that is hard to debug on other peoples machines.

Currenly, I’m working on an NME rewrite to remove GPL code from the iPhone target, and to help integration. Now that hxcpp has reached a certain level of quality, the diverse projects are starting to coalesce and I’m pushing ahead with a complete hxcpp/nme/iphone solution which should be very useful.

Looks like 2010 may be the year it all comes together (hopefully!).

FastCGI For Neko On Share Hosting

In my previous post, I described you could setup neko web services on a shared host, using CGI. This method is not as efficient as it might be because a separate process is required for each request. However it is possible to extend this to “Fast CGI” (FGCI), which starts a single process, and keeps it alive. Apache talks to this over a socket, sending requests and receiving data and a very efficient manner.

If you got CGI working, and your server supports FCGI, then the transition on pretty simple.

The first thing to do is to download the new “fastcgi” haxelib. From a shell use:

haxelib install fastcgi

If haxelib asks you for a project directory, the following discussion assumes you specify your “haxeneko/lib” directory. There is one bit of housekeeping you should do at this time – copy the “nekoapi.dso” object from “~/haxeneko/lib/fastcgi/0,1/ndll/Linux” into your “~/haxeneko” directory. This ensures that this dso will be found when neko is run by the web server.

Now it is time to change the cgi script. The code is very similar, except the extension should be “.fcgi”. Here is the script I used Site.fcgi:

#!/bin/sh
export HAXENEKO=~/haxeneko
export LD_LIBRARY_PATH=$HAXENEKO
export PATH=$PATH:$HAXENEKO
export NEKOPATH=$HAXENEKO
export HAXE_LIBRARY_PATH=$HAXENEKO/std
cd ../../site
exec neko SiteFCGI.n

Note the final “exec” call to ensure the pipes are all correctly plumbed. And the obvious change to the .htaccess file (.fcgi extension):

RewriteEngine on
RewriteRule \.(css|jpe?g|gif|png)$ - [L]
RewriteRule ^(.*)?$ cgi-bin/Site.fcgi [L]

Finally, compile the “Test.hx” file that came with the fastcgi lib. I have a slightly altered version here:

class Test
{
   static var processed = 0;
   static public function main()
   {
      // Called in single threaded mode...
      fastcgi.Request.init("");
      // This can be called multi-threaded...
      var req = new fastcgi.Request();
      while( req.nextRequest() )
      {
         req.write( "Content-type: text/html\r\n" +
            "\r\n" +
            "<title>Neko FastCGI<title/>" +
            "<h1>Fast CGI</h1> Requests processed here: " + (processed++) );
         req.write( "\n page = " + req.getParam("REQUEST_URI") );
         req.close();
      }
   }
}

This version prints the request uri too. To compile, use: haxe -main Test -neko SiteFCGI.n -lib fastcgi

And that should be that! When you visit your web page, you should see the “processed” counter increase, verifying that it is the same process that is running.

Currently the system does not support easily killing the FCGI process, which is something that you must do when you update the “.n” neko file. The only way at the moment is to use the shell to do “ps -x” to identify the process number, and then “kill -9 number”, where number is the process number of the neko executable.

Neko on Shared Hosting

I started to think about using neko web technology, but since I have shared hosting, it was not obvious now this could be done. Currently I’m with site5.com, which is very cheap for running multiple websites, but since it is shared hosting, you don’t get to install anything. However, it does have few features that made getting a neko site up and running quite possible. The key features are:

1. Shell access – not really required if you can copy files to the site (eg, via ftp) but very useful for debugging and getting things going. The shell I have is “jailshell”, which I think prevents directory listings outsite your home directory, but otherwise is pretty functional (based on bash).
2. gcc access – again, not really required once things work, but as you will see, pretty much required if things go wrong. And also good if you want to compile a c++ target!
3. CGI access. Since we can’t modify the apache installation, the only way we can get our code to “run” is via and external process – this is what cgi is for. I will talk a bit about “fast-cgi” later (once I get it going).

First thing is to check you have cgi access. When I first set up the site, I have nothing but an empty “cgi-bin” directory. To test this create a file “test.cgi” in there containing:

#!/bin/sh
echo "Content-type: text/plain"
echo
echo "Hello from CGI!"
set

If you get a “500 – server error” at this stage, it must be fixed. The error is spectacularly unhelpful – not sure where to find the additional error info. Start by trying to run the file from the command line, ie type “~/www/cgi-bin/test.cgi” (assuming this is where your script is located). You should see the output, or perhaps a better error message. Also check for “execute” permission for “all”, as the apache server will run this script with limited privileges. Finally, make sure you have specified a “Content-type” and an additional blank line in the output.

Ok, now we have cgi working! Next step is neko – and haxe too since I will be doing some compiling on the server to help with testing. Haxe is not strictly required if you are deploying pre-compiled solutions.

The hard way

As I said before, you can’t “install” anything on the shared host (no package managers, so it all has to go in your home directory. First thing I did was to download the linux binary distro from nekovm.org. This is easy with the magic “wget” shell command. With your desktop browser, go to the download page and find the link – right click and “copy” the link address. Then go the the shell (putty) window and then paste the link in so you get something like “wget http://nekovm.org/_media/neko-1.8.1-linux.tar.gz?id=download” – hey presto a gzipped-tar file (may have a funny name -that’s ok. Try to use “tab” for tab-complete the filename to save typing). Make a suitable directory and “tar xvzf file” the file to extract the neko files. Now go to the directory and try to run neko. (ie, “./neko”).

You will probably get an error like “libneko.so not found”. But it’s right there, wtf? So you need to set you LD_LIBRARY_PATH (“export LD_LIBRARY_PATH=~/dir/neko-1.8.1-linux”).

Ok, now you get libgc.so.1 is missing, which indeed it is. The easiest way I found to fix this was to use wget to download the source from “http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc.tar.gz”, unpack it, “./configure” it and “make” it. You end up with the required libgc.so.1 file in the “.libs” directory, which I then copied to be next to the neko executable. And now “./neko” works – apparently. I will save you the suspense – you also need to do the same thing with “libcpre” from “http://sourceforge.net/projects/pcre/files/pcre/7.9/pcre-7.9.tar.gz/download” – I use the 7.9 version, not sure if 8.0 works. This is required for haxelib later.

See, I told you that compiler access would come in handy.

Ok, neko done, time for haxe. Again the installer is not much use, so I downloaded the binaries from “http://haxe.org/file/haxe-2.04-linux.tar.gz”, however when I went to run this, I found the “tls” library required a GCC 2.4 runtime, which I did not have, and could not up grade. So – you guessed it linux fans, compile from source. One small hump to get over first, haxe requires ocaml to compile. Of course, ocaml is not installed, but if you are still with me at this stage you know the answer – compile from source. So “wget” it, and here is the trick – make a ocaml directory in your home directory (or somewhere under it), extract the source and use “./configure -prefix your_ocaml_dir” – this provides the “install” directory, since ocaml can’t be used without installing it. The the make is 3-phase “make world opt install”, and now you should have a ocaml install. You will need to put this in your executable path before you can think about compiling haxe.

The online doco suggests that you download and run “install.ml”. I tried this, but the cvs timed out. So I ran this on my windows box (already had ocaml installed!), tarred up the result and ftp-ed it over to my site. Painful, but it worked. One thing is that this uses the cvs “head” – anyone know where to get the 2.0.4 source tar-ball? Once I had the source, I commented out the “download” call in install.ml and “ocaml”ed it. And haxe was built. The haxe distro has a “tools” directory under it, and you can build “haxelib” if you have neko setup correctly.

Getting the paths right is a bit tricky, so I decided to simplify things. I made a directory “haxeneko” in my home directory and “cp -r *” the files from the neko distro (including the new gc and pcre libraries) into this new directory. Also, I copied the bin/haxe built executable in there, and haxelib too (once it was built). Finally, I copied (“-r”) the “haxe/std” files from the haxe distro into this directory too. Now I have everything required in the one spot – and you can too!

The easy way

I have saved you the pain, and you can simply download the files from haxeneko-1.0.tgz. So you should be able to “wget” this, untar it and be almost ready. You may run into problems if there is some incompatible library somewhere – in which case, back to the hard way for you!

Finally, we need to set up the paths. Because my hosting provides the “bash” shell, this setup goes in ~/.bashrc. The required “install” is:

export HAXENEKO=~/haxeneko
export LD_LIBRARY_PATH=$HAXENEKO
export PATH=$PATH:$HAXENEKO
export NEKOPATH=$PATH:$HAXENEKO
export HAXE_LIBRARY_PATH=$HAXENEKO/std

You may need to login again for this to work (or you could paste it directly to your command-line), but now you should be ready to compile some code!

Start by creating your site-code in a directory that is not under you www (public_html) folder – I have called mine “site”. And here is a simple example haxe file:

class Site
{
   public function out(inString:String)
   {
      neko.Lib.print(inString);
   }
   public function new()
   {
      out("Content-type: text/plain\n\n");
      out("Hello World!\n");
      out("Page : " + neko.Sys.getEnv("REQUEST_URI") + "\n" );
   }


static public function main() { return new Site(); }
}

which can now be compiled with “haxe -main Site -neko Site.n”, and tested with “neko Site.n” to give:

Content-type: text/plain

Hello World!
Page : null

Alright – I think you can see where I’m going here, but we are not quite there yet. The problem is that the setup variables in the .bashrc file are not used by the apache server. Apparently, you can use “SetEnv” in a .htaccess file to get this to work, but I could not get it to (maybe the module was not enabled). But all is not lost. You can simply use a script to launch neko. Back in the cgi-bin directory, you can replace the “test.cgi” script with a “Site.cgi” script containing:

#!/bin/sh
export HAXENEKO=~/haxeneko
export LD_LIBRARY_PATH=$HAXENEKO
export PATH=$PATH:$HAXENEKO
export NEKOPATH=$HAXENEKO
cd ../../site
neko Site.n

Now point your browser at http://yoursite.com/cgi-bin/Site.cgi, and you should see the glorious neko output:

Hello World!
Page : /cgi-bin/Site.cgi

Now creating a bunch of cgi files is painful, and you do not want users to see this kind of implementation details, so we use one more trick – the almighty “mod_rewrite”.

In your base “public_html” (www) directory, create a file called “.htaccess”, and add the following lines:

RewriteEngine on
RewriteRule \.(css|jpe?g|gif|png)$ - [L]
RewriteRule ^(.*)?$ cgi-bin/Site.cgi [L]

This leaves the css and image files in the www directory, but it redirects all other URLs your neko script, where they show up in your REQUEST_URI. So now if you use the URL “http://yoursite.com/some_dir/file.html?param=abc&other=xyz”, you get the output:

Hello World!
Page : /some_dir/file.html?param=abc&other=xyz

Now the world (wide web) is your oyster – you can parse the URL anyway you like, and generate any output you like.

This certainly gets you up and running with neko on a shared-hosting web server. One problem is that 2 processes are created for every request. I have done a some initial work with the “fast-cgi” interface, and think I should be able to get this going, in which case there should be a big boost in efficiency.

There should also be no reason why you could not compile the site to a c++ native executable. However, this may reduce your ability to use the neko “.n” template system.

Quick Update

Just a quick update to let you know things are still moving forwards. I have not done very much iPhone specific stuff recently, but I have been working on the graphics code base in general. The idea is to separate the graphics code from SDL (although still use SDL most of the time) to avoid GPL issues and also allow the library to be used in a wider set of applications rather than just games. For example, inside a window in a larger desktop application, or inside Google’s Native Client plugin. Another goal is to improve rendering speed by minimising the amount of data moved between haxe and the graphics code – this involves moving code logic from haxe into c++. I have also been looking at a few minor tweaks such as setting object widths/alphas like flash does.

Once this is done and moved into Neash/NME, I will fix a few of the remaining issues on the C++ backend – maybe even get to add dynamic properties to the runtime. I would also like to spend a bit of time finishing off the internal garbage collection to make it thread-safe and run automatically – this could solve some of the problems compiling boehm-gc on various systems.

And, of course, I would like to write more tutorials…

Switched to IMMIX for Internal Garbage Collection

I did a little bit of profiling on the iPhone and found a bit too much time was spent doing garbage collection. The hxcpp runtime has 2 modes – “Boehm GC with explicit statics” and “internal”. The former is from a standard and robust code base, with the latter uses built in code with explicit marking. I added the second mode because Boehm GC was just too slow on the iPhone – not sure why because it is pretty good on the other platforms (maybe I missed a configuration option).

The internal GC has some restrictions that make it mainly suitable for games. These are: the collection must be triggered explicitly, since no stack searching is done, which is most easily done once per frame. And it is not thread safe, which can be worked around. Within these confines, many different schemes can be tried. My first attempt could probably be termed “Naive Mark and Sweep”, and used free lists. On Windows/Mac this underperfromed Boehm GC, but on the iPhone, worked better.

The current scheme is now “Simplified IMMIX“. It is simplified because it is single threaded, and I have not implemented overflow allocation, defragmentation (although there are hooks in there for moving) or any generational stuff. I think overflow allocation should be easy enough, and defrag should not be too hard in some form or other. The insertion of write barriers for generational control may also be straight-forward using the “operator =”. I may also change the code generation to separate stack variables (local, function args) from member variables since in the current scheme, stack variables never form roots, and therefore would not need to use write-barriers.

Anyhow, on the “Physaxe” test, which creates lots of small list objects per frame, the Naive GC got about 51fps, Boehm GC got about 65fps and IMMIX got about 69fps – so a bit of a win there. For this test, I triggered all collections exactly once per frame. The difference between Naive and IMMIX is significant, and this perfromance gain also translates to the iPhone, which is good news.

Since the internal scheme is precise, I feel it should be able to outperform Boehm GC by a bit more, and maybe the extra could come from a generational system. The code is actually not that complex (1 cpp file, 1 header file) so any budding GC researchers may want to see what they can do.

Currently, the internal GC is default only for the iPhone, but you can try it on other platforms by changing the #define in hxGCInternal.h. The reason for this is the restrictions mentioned above – the easiet way to conform to these restrictions is to enable the “Collect Every Frame” in neash.Lib. To remove these restrictions, I will need to find some way of stopping the world (safe points?) and some way of capturing the stack (code mods to allow objects to push themselves on a shadow stack?), both of which are very doable, although I’m not sure on the effect on performance.

Haxe, iPhone & C++ At Last

Hxcpp 1.0, neash 1.0, NME 1.0

The release this week of haXe version 2.0.4 officially includes c++ as a build target, for Windows, Mac, Linux and iPhone. You can download and install from haxe.org. In addition to the standard includes, you will need the “hxcpp” library, which can be insatlled with the included haxelib management tool.

Coincident with the hxcpp release, I have updated the neash and NME libraries to versions 1.0. You can also download these via the haxelib tool too. There are several incrental improvements, and the iPhone target has been added!

Getting started with the iPhone

Getting started with the iPhone is quite tricky at the moment, mainly because of the pain of setting up an Xcode project. Also, getting the simplest program onto the device is hard due to the code signing requirements. So if you can already get one of the existing application templates to work, you are half way there.

Note that this solution uses the “SDL” library, and must statically link against this. SDL is covered by the LGPL license, and this has implications should you choose to release your software. I am hoping to remove the LGPL restiction at a later date.

The binaries used here are have been compiled for the “2.2.1″ iPhone SDK. So choose this version when compiling for simulator or device.

1. Download and install components
   • Get haxe & neko: Visit haxe.org
   • Get hxcpp: haxelib install hxcpp
   • Get nme: haxelib install nme
   • Get neash: haxelib install neash
   • Get the sdl-static libs for iphone: I have created a project with binary builds of these. You can get the latest builds directly from subversion svn code at: http://code.google.com/p/sdl-static/source/checkout. Or get the snapshot bundle from this site and install somewhere handy: sdl-static-iphone-1.0.zip
2. Get Xcode with iphone sdk support – visit apple.com
3. Get a Developer key (you can try simulator without it). You will need to pay to sign up as a developer on the apple site.
4. Fire up Xcode and do File > New Project.
   Choose iPhone OS > Application. Here choose a “Windows-Based Application” but infact we will use the delegate setup in the SDL code, so we will have to delete the one created by the wizard.
   Select a name & directory for the project. I’m calling it “Haxe Test”.
   Now as it stands, you should be able to build for the Simulator and get a lovely white screen and a program called “Haxe Test” in the simulator start screen.
   Next thing is to delete(to trash) the “…AppDelegate.h” “…AppDelegate.m”, the “Nib Files” group, Resources/MainWindow.xib and “main.m”.
   Finally, select the “Haxe Test” executable (in the Targets section) and from the “Get Info” – “Properties” tab, clear the reference to “MainWindow”.
   We will add replacements for these soon.
5. Add “main.cpp” from the NME project.
   Select the top-level project folder and then use Action > Add > Existing Files. It is probably in /usr/lib/haxe/lib/nme/1,0/ndll/iPhone/ or similar depending on which version of NME you have installed. It can be very painful to get xcode to load from this location, unless you hit Command-Shift-G at the “Add” dialog and type (at least some) of this filename in.
   Choose to “Copy to destinations folder” so that you can mess with it if you wish. Note: you need to have a cpp mainline in order to automatically link in the correct runtime libraries.
6. Add the libNME.iphoneos.a and libNME.iphonesim.a files from the haxelib NME project.
   You can add them both and the linker will select the correct on depending on your build. They are in the same place as main.cpp, you you should be able to use “iPhone” from the pull-down box in the add dialog. Probably best not to copy these files – in case you want to change them at some stage.
7. Add the whole sdl-static/lib/iPhone directory.
   Again probably best not to copy. I used the “Recursively create groups” option. These will be where you stored them in step 1.
8. Add the whole hxcpp/bin/iPhone directory like above.
   Again, this will be in a path like /usr/lib/haxe/lib/hxcpp/1,0,2/bin/iPhone/.
9. Add the hxcpp include directory to the include path.
   Use the “Info” button to get the project properties, and on the build tab, under “Search Paths” add something like /usr/lib/haxe/lib/hxcpp/1,0,2/include/ to “Header Search Path”
10. Now we are ready for the haxe code. If you have and existing project, then you can adapt the following instructions.
    Create a new file from Xcode (Other/Empty File] Here I have called it “HaxeTest.hx”, and unticked the “Targets” option. I’m prety sure there is a way to get “Haxe File” to appear as on option here – but I don’t know the details.
    
    In the haxe file, enter something like (Note the window size): import flash.display.Sprite; import flash.display.Shape; class HaxeTest extends Sprite { public function new() { super(); flash.Lib.current.addChild(this); var circle:Shape = new Shape( ); circle.graphics.beginFill( 0xff9933 , 1 ); circle.graphics.drawCircle( 0 , 0 , 40 ); circle.x = 150; circle.y = 200; addChild( circle ); } static public function main() { neash.Lib.mOpenGL = true; neash.Lib.Init("HaxeTest",320,480); neash.Lib.SetBackgroundColour(0x447733); new HaxeTest(); neash.Lib.ShowFPS(); neash.Lib.Run(); } } This is the “main” file for haxe, and the hxcpp compile will create a library matching this class name.
11. Set up a build script to build changes you make to your haxe files into a library.
    Xcode has a few issues with a straight custom build script order due to incorrect dependency checking. This can be worked around by first adding a custom target.
    Highlight the “Targets” in the Groups & Files and use the “Action > Add > New Target..” Choose “Other > Shell Script Target” and call it something like “Compile Haxe”. Close the pop-up and go back to the explorer. There should be a “Run Script” entry under the “Compile Haxe” target if you expand it out.
    
    Get info on “Run Scipt” and enter the following script if [ "$CURRENT_ARCH" = "i386" ] then haxe -main HaxeTest -cpp cpp -lib neash -lib nme --remap neko:cpp --remap flash:neash -D iphonesim else haxe -main HaxeTest -cpp cpp -lib neash -lib nme --remap neko:cpp --remap flash:neash -D iphoneos fi You can untick the “Show Environment” if you do not need to debug this.
    One last step – drag the “Compile Haxe” target into the “Haxe Test” target. It should now also show up as first item “under” the “Haxe Test” target. The build order should now be correct. (See image at end of post)
12. Now you are ready to do the build. The first time you build, the build results will show “Running custom shell script…” for quite a while. Haxe compiles to cpp very quickly, but it take a while for the cpp files to compile to a library. You can see the progress if you expand out the middle tab bit.
    At this stage, you should get a bunch or errors when linking, but also haxe should have created a library for you. Add this library to the project - it should be in the local cpp/HaxeTest.iphonesim.a.
13. Compiling now gets a bunch of unresolved functions from frameworks.
    Add the following frameworks to the project (Add > Existing Frameworks):
    • QuartzCore
    • OpenGLES
    • AudioToolbox
    These can be found in /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS2.2.1.sdk/System/Library/Frameworks/.
14. Run!
    So you should be good to go. Open up the debug console so you can see any traces/printfs.
15. Change the target to “Device – IPhone OS” from the pull-down and hit “Build and Go”. Again, this takes quite a while the first time.
    Now add the new cpp/HaxeTest.iphoneos.a library to the project.
16. Now you need to sort out your code signing. If you have not done so already, setup you apple developer account & certificates on the apple web site.
    Go to the info of the “Haxe Test” executable and the “properties” tab. Change the “Identifier” to match one of your cerificates. Make sure to match your company URL. You may want to use “*” when creating your profile for easy changing.
    
    Under the “Build” tab, under the “Code Signing” bit in the “Any iPhone Device” pull down your profile. If you don’t have one then you will need to create one on the apple website.
17. Connect up your iPhone(iPod touch) and build! W00t!

I have had all sorts of errors when trying to upload to the device. So far, they have been solved by getting out of the car, walking around it and getting back in. ie, Disconnect and power down ipod. Fully exit Xcode and the start it all up and try again. Also, uninstalling the app from the “Windows > Orgainiser” directory can help.
But now the easy bit. Change to HaxeTest.hx file, and hit Build & Go. It is that simple. Errors should show up nicely in xcode.
You can add data files (eg, pngs, xml etc) to the project and they will be copied to device so you can open them with a relative path.
In the properties of the “Info.plist” you can set a Icon File – don’t forget to add the icon to the project too.
Not covered here (because I have not fully sorted it out myself):

• Syntax highlighting in XCode
• Debug build (hxcpp can do then – it’s a matter of setting up Xcode)
• Code completion in Xcode
• Automating this procedure!

Edit: Add framework path, SDL version, MainWindow clearing.

Haxe on the iPhone – For Real!

To progress this project a bit further, I needed a real device – so I convinced the little woman that an iPod touch would be a good thing to have around. She seems to have taken to it, so now I’m thinking I may need one each .

After much phaffing about, I’ve finally managed to get stuff running on the actual device. I had to comment out quite a bit of NME, since I only used the base SDL, not all the extras. Boehm GC was also a bit tricky because I didn’t really know what I was doing, but I brought in some bits from the mono project and then disabled USE_MUNMAP because it caused it to crash. In the end, it seems to work – no crash, but then I may not have been running it long enough. I will have to try some memory thrashing later.

One thing I found with Xcode is that if you ever change the project name/AppID settings then you really need to clean the project, exit Xcode and get back in. But the hardest part was working out where to go the get the developer certificate! I guess I’m a bit thick, or missed the meno, but it took me ages to get to the web form to create a certificate.

So the big question is perfromance. In this demo, initally, it runs at about 2.5 frames a second (I don’t have a fps counter yet), but slows a bit later when things spread out. But this is using the high-quality, anti-aliasing software renderer. Next job is to hook up the OpenGLES renderer, then I’ll really know where I stand. But overall, pretty positive result I think.

A Second Look (iPhone + Haxe)

Once the basics are in place, the rest comes pretty naturally.

Just a slight tweak to the MovieClip transformation gets Physaxe doing it’s thing.

Performace seems ok-ish in the simulator, not sure how it woud go on the real device.

Haxe on iPhone (Simulator) – First Look

iPhone Dev

The iPhone SDK requires you statically link everything, and I wanted to make it easy as possible to change haxe code -> generate cpp -> link to Xcode -> test of iPhone (or simulator). The solution I am currently using is to generate a library from the haxe code using the standard command line make, and include this library in the Xcode project. I hope to add a “pre build” step to drive the make system automatically.

Hxcpp executables typically use the “NME” library for graphics, which is in turn based on libSDL. The good news is that the source version of libSDL compiles for the iPhone! I tried the svn download first, but this does not seem as nicely bundled as the Apirl 13 version, which worked very nicely indeed (besides a small problem with RenderRect args changing).

Getting the hxcpp backend to generate a library was almost trivial – you take the same obj files and put them in a lib instead of an exe. The only minor difference is you do not explicitly create a “main” (ie, program entry point) call, but instead create a function (currently called __hxcpp_lib_init) that the user supplied main line must call. This may also be good for windows applicaions that want to use a “WinMain” instead of console based main function.

Compiling the hxcpp runtime as a static library was also pretty easy after the post 0.4 code reorganisation that assimilates thirdparty code rather than linking to it. Again, it was a matter of taking the same objs and putting them in a lib instead of an dso. Initally I got link error when linking with Xcode, but if you include 1 real, small c++ file in the project, these link error go away.

Compiling “plugin” modules as static libraries (eg, NME) was slightly more difficult. I could use c++ static initialisation to auto-register the exported functions, if I could get Xcode to link to the required obj. To force objs to be included, I needed to put a special symbol in each cpp file that exports functions, and make reference to these from the main code base. It is really only something that needs to be sorted out once, and it is done now, so it should not really be a problem any more.

I also have to cull out quite a bit of code (eg fonts, image loading, opengl & sound) from NME, but I can look at adding these bits in one by one.

The astute ones among you will notice that the colour of the above circle if RGB/BGR reversed. This is something that will obviously need to be fixed.

Not being used to Xcode, it took a bit of getting used to – things like frameworks etc. However, I think that ultimately, we could end up with a very nice solution. The idea would be to create frameworks for hxcpp and nme, and a project template to link it all together. You would then create a project from the template, modifiy the boiler-plate haxe code and hit build. This would also be good for standard mac apps (rather then iPhone apps). Still a way off this, but moving in that direction.

SDL, LGPL and you

Dynamically linking against SDL (or NME) normally discharges your obligations to the GPL, however in this case, we are statically linking to it so there are still some issues. However, all is not lost because my interpretation is that you must allow others to relink your application. (ie “so that the user can modify the Library and then relink to produce a modified executable containing the modified Library”, where Library is “SDL”). So you must forefiet your hxcpp compiled library file (rather than haxe or cpp source), as well as you project files (which should be boiler-plate anyhow). So this is actually borderline acceptable, although I will work towards a GPL free solution).

Some Help Getting Started With Hxcpp

Tony at touchmypixel.com has posted some very useful information to help you get started with hxcpp. Be sure to go over there and check it out.