Simple Extension for Mac

[Al Hart]

I am referring to the old C++ "Simple Extension" from several years ago.

But we would rather start the Mac project with the latest and greatest.

Is there something new, (e.g. new C API) which can be used to integrate C-code with SketchUp Ruby? If so, please point us in the proper direction.

Thanks,

Al

[thomthom]

That was for reading and writing SketchUp files. Not to run from within.

Got a link to this C++ "Simple Extension"?

[Al Hart]

You can download a copy from here:

http://www.renderplus.com/downloads/SimpleExtension.zip

It has a read me file, and with a little work to get it to work, it actually works.
(You have to have Ruby installed on you own machine when you compile and link it, for example)

SketchUp sent it to me about 6 years ago, and although they don't publish or support it, they did give me permission to pass it on to others.

You might have a lot of fun with it.

• You can create functions in C++ and call them directly from SketchUp.

• You can create ruby classes in C++ and access them from SketchUp

• You can call your own SketchUp functions from C++

• and you can access the SketchUp ruby classes directly from C++:

For example, this code, although it is more complex to write in C then in Ruby, gets the value of SketchUp.active_model.rendering_options["ModelTransparency"] directly from the C-code

	Sketchup = rb.find_class("Sketchup");
	model = rb.run_func0(Sketchup, "active_model");
	member = rb_intern("[]");
	rendering_options = rb.run_func0(model, "rendering_options");
	options_value = rb_funcall(rendering_options, member,1, 		rb.CString_to_value("ModelTransparency"));

	bir_skp_xray_mode = rb.value_to_bool(options_value);

If you get stuck getting it to work in Windows, I can help. But I could sure use some help from someone who knows more about compiling, etc. on the Mac than I do to get a version running for the Mac

[thomthom]

Right, so it's a Ruby C Extensions written in C++. You might get some hints to building on SU from the simple Hello World Ruby C Extension sample I posted at BitBucket: https://bitbucket.org/thomthom/sketchup-ruby-c-extension

It got notes on how to compile on Windows and OSX. People would find that while they could compile a Ruby C Extension for plain Ruby - it would crash under OSX unless some specific compiler flags where set.

[slbaumgartner]

@al hart said:

You can download a copy from here:

http://www.renderplus.com/downloads/SimpleExtension.zip

It has a read me file, and with a little work to get it to work, it actually works.
(You have to have Ruby installed on you own machine when you compile and link it, for example)

SketchUp sent it to me about 6 years ago, and although they don't publish or support it, they did give me permission to pass it on to others.

If you get stuck getting it to work in Windows, I can help. But I could sure use some help from someone who knows more about compiling, etc. on the Mac than I do to get a version running for the Mac

This sounded interesting, so I downloaded it and took a quick look. It creates a Windows DLL (dynamic link library). The organization and structure of a DLL are very Windows-specific. Mac also has dynamic shared libraries, but their organization and structure are completely different. It would require a significant rewrite to get this over to the Mac; no doubt feasible, but way out of my depth!

Steve

[Al Hart]

@slbaumgartner said:

It would require a significant rewrite to get this over to the Mac; no doubt feasible, but way out of my depth!

Steve

Exactly what I am looking for - a Mac expert, or at least someone who is more familiar with Mac than I, who has done this already for SimpleExtension, or has created a C-code to SketchUp ruby interface which does something similar, or who can easily figure out how to write a Ruby Extension, based on SketchUp's Simple Extension, and could share it with us.

[driven]

@TT

and all, I finally got around to installing your example, and have a few notes for others...

=== Compile Instructions ===

type/copy-paste or drag and drop items between ][ ][

1. Open a Terminal.app window 
2. cd into the project folder and enter
  ] cd  [drag folder into terminal] [ >> return
3. Execute "ruby extconf.rb"  using full path by dragging
  ] ruby [drag file into terminal] [ >> return
4. Execute "make"
  ] make -f Makefile [ >> return
5. Move to "User" Plugins  using the proper folder for v2013   
  ] mv -f SX_HelloWorld.bundle /Users/johns_iMac/Library/Application\ Support/SketchUp\ 2013/SketchUp/Plugins [ >> return 
6. Open SU
  ] open /Applications/SketchUp\ 2013/SketchUp.app [ >> return 
7. Open "Ruby Console" and enter
  ] require (Sketchup.find_support_file("Plugins/SX_HelloWorld.bundle")).to_s' [ >> return
8. Test 
  ] SUExtTest.knock_knock [ >> return

success = Hello SketchUp World! 

NB; in extconf.rb match your environment [ $CFLAGS = '-arch x86_64 -arch i386 -O3 -pipe'] works for me

@Al
I'll have a look at yours and see if I can make any sense of it... no promises,

john

[thomthom]

Had a look at it myself. Looks like a Ruby C Extension wrapped in C++ with extra stuff I expect if for the exporter.

Al: The Ruby C Extension sample I linked to is a bare bone example of connecting Ruby and C. Now, it is possible to write these extensions in C++, I've seen examples - they had to extern the C++ functions as C type functions.

That SimpleExtension sample didn't seem that simple to me, certainly more than the minimum of what is needed. Look at how people in the Ruby community is developing Ruby C Extensions with C++ and you will find simpler examples.

[thomthom]

StackOverflow got several threads on it:
http://stackoverflow.com/questions/10167149/compiling-ruby-c-extension
http://stackoverflow.com/a/2060716/486990

Noel Warren have used Rice:
http://rice.rubyforge.org/

And just found this which was interesting in regard to raising exceptions:
http://old.thoughtsincomputation.com/posts/ruby-c-extensions-c-and-weird-crashing-on-rb_raise

[olilej]

I looked over that SimpleExtension example, it seems very promising.

By the way, what exactly are the real benefit of using Ruby C Extension ? Does this have to do with performance ? As in SketchUp 2013, C++ SDK doesn't allow model interaction, it would be very interesting if we could improve the plugins efficiency with that possibility.

Olivier

[thomthom]

I use C Extensions when I need to do many calculations. Vertex Tools became 200+ times faster in calculating the soft selection when I ported the code to C Extension.

Just calling Ruby functions won't be faster. You'd have to be doing calculations and other processing for it to be faster.

It's not just performance though, you might want to spawn off other processes. Use C libraries.

[Al Hart]

We had about the same experience as ThomThom.

Calling ruby functions from C-code was slower than calling them from ruby directly in SketchUp.

e.g. The C-code replacement for:

value = model.get_attribute “dictionaryname”, key, defaultvalue)

can be done directly, (actually rather indirectly), from C-code, but the execution time is slower than in SketchUp ruby.

But other things, such as maintaining a table for vertices, and then doing special processing for vertices was faster.

Also, we were able to use Windows dialogs, functions in other Windows DLLS, etc. and attach them to SketchUp.

Also, we were able to use all the Ruby stuff from C++ because ruby\1.8\i386-mswin32\ruby.h, (part of the ruby code), includes

#if defined(__cplusplus)
extern "C" {
#endif

---

Back to the original question.

Has anyone interfaced to C routines from the Mac, and if so could you share a sample of some sort to get us started...

[thomthom]

@al hart said:

Has anyone interfaced to C routines from the Mac, and if so could you share a sample of some sort to get us started...

404 — Bitbucket

(bitbucket.org)

[Al Hart]

@thomthom said:

404 — Bitbucket

(bitbucket.org)

Thanks, ThomThom, that looks like what I am looking for.

I see you had posted it before, but I didn't know what it was at the time.

[thomthom]

Mind you, I recently found http://rubyinstaller.org/downloads/ which I think is a better choice for Windows than the Visual Studio solution I'd used.

[olilej]

I've been playing around with C Extension recently and I would like to know how if there is an equivalent of is_a? ruby function in C level.

I found rb_obj_is_instance_of but it seems to be only meant for native ruby types.

[Al Hart]

[Ignore this for a minute - I need to add a second parameter for what the value to pass to is_a?]

You can execute the equivalent of any ruby function using rb_intern() and rb_funcall()

Try this:

VALUE fid = rb_intern("is_a?");
VALUE vret = rb_funcall(klass, fid, 0);

[Al Hart]

Here is a better example, equivalent to

Sketchup.is_a?(Module)

VALUE Sketchup = rb_path2class("Sketchup");
VALUE Module= rb_intern("Module");
VALUE is_a = rb_intern("is_a?");
VALUE result = rb_funcall(Sketchup, is_a, Module, 0);

[Dan Rathbun]

@olilej said:

I've been playing around with C Extension recently and I would like to know how if there is an equivalent of is_a? ruby function in C level.

If you have the CHM... you can click on the method description, and the C source will popup:
(Also works for online version, but the source link must be clicked directly, and is only visible when the mouse is hovering over the method description.)

[Dan Rathbun]

So it looks like there are some macros defined in C, to make life easier ... CLASS_OF(), RCLASS_SUPER(), etc.