Plugin DLL

Alienizer

Assuming that you have a ruby script with only the following line...

require 'TestPlugin.dll'

Using the 2.0 type library I have the complete set of commands and properties available, and the TestPlugin.dll does load when Sketchup starts, but I don't know how to get the Sketchup CoSkpApplication interface! If I use Connect, it stalls forever.

Does anyine knows how this works? Does Sketchup sends something to the DLL when it loads? Or is there a callback of some sort, anything?

This link shows an example how to get the Application interface if you have the document object, but how do you get the document to begin with!?

Reading Textures from a SketchUp Model Using the Reader SDK

Posted by Sang Ahn, SketchUp Software Engineer In case you haven't looked yet, we have an SDK that allows you to read SketchUp files using ...

(sketchupapi.blogspot.com)

Thanks

Dan Rathbun

In Ruby..

doc = Sketchup.active_model

Alienizer

@dan rathbun said:

In Ruby..

doc = Sketchup.active_model

Yes I know, but how do you get the "Sketchup" object in a DLL when it loads?

Dan Rathbun

@alienizer said:

..., but how do you get the "Sketchup" object in a DLL when it loads?

Look in your SDK \SkpReader\Documentation
folder for file:
_write_textures_and_u_vs_8cpp-example.html

This forum is used by mostly Ruby guys, so you should probably post your questions in the C++ SDK forum at Google Groups (where most of the C++ guys will see them.)
http://groups.google.com/group/su-sdk-fileshare/topics

Alienizer

Thanks Dan

Al Hart

You need some sample code called Simple Extension.

SketchUp doesn't seem to make it available, but they will let me send you a copy. See this thread: http://forums.sketchucation.com/viewtopic.php?f=80&t=13548

Send an email to al.hart@renderplus.com and I will try to send you a copy (if I can find one)

The "secret" is that you create a dll called, for example, ABC.DLL, then do require('ABC.dll'), (with the proper path, etc.), SkethchUp will load it and make a call to Init_ABC() (the name of your DLL) and you take it from there.

The sample DLL is linked with Ruby DLLs and cann access and modify SketchUp classes and more.

Alienizer

That's exactly what I'm after Al. I sent you an email. I appreciate all your help.

Al Hart

@alienizer said:

That's exactly what I'm after Al. I sent you an email. I appreciate all your help.

I found my previous emails and found a link to it, and sent it off to you.

Good Luck! (There is nothing easy about figuring this out and getting it to work.)

If you have some questions, post them here.

Alienizer

Thanks Al, this will help me so much I appreciate your time and super fast reply.

thomthom

I wonder if we ( the community ) can set up a wiki page for how to create C extensions for SketchUp? It'd really help people getting into it.

Al Hart

We could put documentation on how to use it in Google Docs - either starting a new one - on on the SuWiki now located in the SketchUp Sage Site

What SketchUp told me was:

@unknownuser said:

I believe Sang has (or will have) simple extensions in our SDK soon, but in the meantime it's perfectly okay to distribute this. The more people who know the techniques, the better.

Here is what I have been sending people:

@unknownuser said:

You can download a copy from:

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

This is basically a Ruby Extension - and SketchUp has created a sample.

This lets you can C-code functions directly from SketchUp ruby, call SketchUp ruby functions directly from C-code, and also access SketchUp classes directly from C-code.

What would be good would be a case study where a new user tries to use it, and points out what it is difficult, gets help, etc.

Alienizer

I totally agree, and we should be able to write plugins entirely in a dll. First, I'm sure it's faster to execute since it's compiled, rather than interpreted by Ruby.

But I think the Sample Extension is incomplete. It will not compile as-is. All the rb_ functions are undefined, unless I'm missing something?

I can now see the concept, but it seems that every calls are passed as text, again slowing down the dll. Might as well write it all in ruby!

What about the Type Library 2.0? This gives us complete access to the Sketchup API, without having ruby as the middle man. If we can get the ISkpApplication interface when the dll loads, we are in business, every API calls are visible, and easy to use, ISkpOptionsManager, ISkpOptionsProvider, ISkpEntities, ISkpCurve, ISkpFileWriter to name a few.

Dan Rathbun

@alienizer said:

But I think the Sample Extension is incomplete. It will not compile as-is. All the rb_ functions are undefined, unless I'm missing something?

You are..

You will need to download the Ruby source (Ruby is written in C,) and include ruby.h (and perhaps tchar.h)
See the ol' Pick-Axe Ruby book chapter: Extending Ruby

Link to SU 8.x Ruby source (v1.8.6-p287) zip
Link to Ruby 1.8.x branch source dir

Al Hart

@alienizer said:

I totally agree, and we should be able to write plugins entirely in a dll. First, I'm sure it's faster to execute since it's compiled, rather than interpreted by Ruby.

After you get the DLL working, you can access and modify SketchUp classes directly from the C-code. However, it turns out that it is somewhat slower to do things in C-code.

So we left most routines which access SketchUp classes in RUBY. We use the DLL to let us access Windows features, use Windows dialogs, etc. Also, things which do not directly access SketchUp classes are much faster in C++.

Dan Rathbun

@alienizer said:

I totally agree, and we should be able to write plugins entirely in a dll.

There is a future pitfall for DLL files. Their support has been removed for the Ruby 1.9.x branch (which we are hoping that Sketchup begins using soon. Unicode string support etc.)
Anyway... the require() method will not load files with a DLL extension in Ruby 1.9.x

You do not need a real DLL file (to write a Sketchup plugin,) unless you are exporting DLL functions for public use by other non-Sketchup / non-Ruby programs.

Compile as a .so (source object) file if a DLL is not necessary.

BTW... you can always use the WinAPI C call LoadLibrary() to load a DLL. You can make the call using the Ruby Win32API.so extension, or Daniel Berger's newer win32-api package.

Dan Rathbun

A few more links:

ruby embedded into c++
Tutorial, Guide, Howto
by Simon neoneye Strandgaard

stackoverflow forum topic:
How to embed Ruby in C++?
... which mentions a textfile that comes with the Ruby source, named: README.EXT

README.EXT.txt

Dan Rathbun

Other threads on this issue:

Getting Started with C++ and Sketchup

Ruby extension module using C/C++ (mostly about using SWIG)

Example of Compiled Extension with SWIG and CMake

Ruby C++ extension crashes SketchUp

Re: Optimization Tips (discussing Ruby vs C speed)

Programming in C, C++ for Mac and Windows?

Are Swig generated Ruby bindings compatible with Sketchup?

Examples:

TBD's SUExt extension example

Dan Rathbun

Added an [Info] page to the [Code Snippets] sticky thread, specifically for C/C++ coding links, etc.

Alienizer

Thanks to both of you, Al and Dan.

But I'm not sure which way to go anymore! I was under the impression that compiled code would run faster than ruby interpreter!!! As of ruby 1.8, the code is interpreted, not compiled into pcode or anything. So that confuses me even more.

So if 1.9 will not load a dll with require(), then there is no more point on writing a dll is there? The reason I wanted to do this in the first place is for speed, and the fact that I can created windows which you can't do in ruby unless you use html, but again, html is limited, and need extra files, javascript etc.

So what do you guys suggest? Which way is best for now and the future? I mean, they way to go about writing plugins? Simply using ruby and that's it? No more COM or anything?

Dan Rathbun

@al hart said:

@unknownuser said:

You can download a copy from:

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

This is basically a Ruby Extension - and SketchUp has created a sample.

What would be good would be a case study where a new user tries to use it, and points out what it is difficult, gets help, etc.

Item (1): coders need to download Ruby source (links here)

Item (2): in the package, file stdafx.h, line 54:
#include "C:/ruby/source/ruby-1.8.2/ruby.h"
needs to be changed to the correct Ruby version source dir, for the plugin's targeted Sketchup version (ruby-1.8.0 for SU < 8, ruby-1.8.6-p287 for SU 8+)

Item (3): WIN Sketchup is a MFC application. The package assumes the user will have a full edition of MS Visual Studio, which comes with the MFC source files.
Visual Studio Express editions do not come with these files.

Express users can manually add the MFC header files, by installing the Windows Driver Kit Version 7.1.0 The download is an ISO DVD image, but some archive apps can open this type of file, such as 7zip, so you need not waste a blank DVD.

If you manually copy the header files from the ISO arhive, it looks as though the header files may need to be copied & renamed, ie: "_afxwin.h_00593" to "afxwin.h"
Then these files either:

moved to the Windows SDK/includedir, or the appropriate Visual Studio include dir, or 1. set VS-Express to use your WDK/include dir, via the Tools (menu) > Options (dialog)

If you install the WDK then you will not need to rename files, and the Installer may ask if you wish to integrate with Visual Studio, so the include paths may be added for you.