Screen Saver

[vanderlin]

I was wondering if it is possible to create a c++ app in objective c. I was trying to use the screensaver.framework for osx to build a screen saver.

Does anyone know if this is possible?

[hahakid]

I found these pretty helpul with making OSX screensavers:


http://cocoadevcentral.com/articles/000088.php

http://cocoadevcentral.com/articles/000089.php


http://www.mactech.com/articles/mactech ... urScreens/

http://www.mactech.com/articles/mactech ... creens102/


/A

[vanderlin]

were you able to compile OF as a screensaver? I was asking memo about it and he said I would need to replace glut.

[hahakid]

I wasn't using OF I'm afraid, just plain C++ and some Objective-C.


/A

[memo]

Now that OF has the glut abstraction in place, it shouldn't be too hard to create an addon to remove glut and provide a native cocoa layer to run openFrameworks - similar to ofxiPhone (e.g. ofxCocoa or ofxOSX). Then you'd have full control of the window creation and there'd be no issues making screensavers (or using other osx frameworks or even making quartz composer plugins!). This has been on my todo list for a while but not had time :o

[theo]

ofAppCocoaWindow now exists:
http://forum.openframeworks.cc/index.php/topic,2200.msg11872.html#msg11872

[moka]

SWEET YEAH!

[memo]

Damn yea!

[theo]

Okay I have OF running as a screensaver.



Webcam seems to work too


Only thing that doesn't seem to work is FMOD because the dylib has to be copied to the MAC_OS folder in myScreenSaver.saver/Contents/MAC_OS . The copying is fine but the @executable_path command we use in the build script for setting the dylib path fails because .saver is not an executable.

There is more info about the issue here:
http://forum.soft32.com/mac/Including-f ... 44390.html

Also I found this gem! A way to debug a screensaver on the command line.

Code:

/System/Library/Frameworks/ScreenSaver.framework/Resources/ScreenSaverEngine.app/Contents/MacOS/ScreenSaverEngine -module RandomWeb -foreground 

RandomWeb being the name of the screensaver.

This is so much better than the generic error System Preferences give you when you have an error in your code.

BTW most of this effort is based on the guide Andreas posted - so big thanks!
http://cocoadevcentral.com/articles/000089.php

Code posted in next post.

[theo]

Okay so here is the example project.

the openFrameworks folder is included in the project folder because I had to comment out some FMOD related code to make it work.

the only other change that is needed is to modify freeimage.h

find the line:

Code:

typedef int32_t BOOL;

and change it to:

Code:

//typedef int32_t BOOL;
#define BOOL int32_t

Also a thing to note is that sometimes the system preferences doesn't re-load the screensaver correctly. so you have to right click on it in the list and remove it and then close system preferences and re-add it.

the screensaver can be found in Build/Debug/

I have not done anything yet in relation to the data/ folder that will come next.

Also be aware of the symbol clash issue described at the end here: http://cocoadevcentral.com/articles/000089.php
Basically it means you might not be able to have multiple screen savers with the same names / class names running at the same time.

Theo

[moka]

great, thanks theo, what target do you have to define for a screensaver?  Is that a .bundle? I could not find .saver type targets so maybe you could clear that up for me.

[theo]

no idea :D

I just took a screensaver template project and hacked OF in.

one thing that would be good is to have two targets for a project - one that builds it as a cocoa window and another as a screensaver - that way it would be a lot faster to test stuff.

[moka]

yes, I just checked it and it seems to be a .boundle. no idea about the details though. Just out of curiosity I will try to build a project from scracth the next days :)

[sth]

Okay I have OF running as a screensaver.
Only thing that doesn't seem to work is FMOD because the dylib has to be copied to the MAC_OS folder in myScreenSaver.saver/Contents/MAC_OS . The copying is fine but the @executable_path command we use in the build script for setting the dylib path fails because .saver is not an executable.

You can adjust the loader_path of the plugin with install_name_tool, set it to @loaderpath instead of @executable_path this will circumvent the problem

For more info do a google search for install_name_tool and loader_path / bundle

HTH,
Stephan

[theo]

oh thats awesome - thanks!
that should do the trick.

I also have the same problem with loading files - currently I have to hardcode the data path in, but I think I should be able to get the screensaver's current path then set that as the data path on runtime.

Theo