Been recently thinking about writing a VST plugin in D.

A VST plugin is a .dll for use with Cubase or other music software. It has a specially named C function as entry point:

AEffect *main( audioMasterCallback audioMaster );

where AEffect is a struct, and audioMasterCallback is a typedef for a function.


1) How do I get these definitions into D? The VST SDK comes with an "aeffect.h" that defines these types and some enums.

2) How do I build a dll with D?

3) I need to compile a "main" function with different parameters than just (argc, argv). VisualC accepts an arbitrary "main" when compiling a .dll, but GCC does not. Therefore, a common workaround with GCC is to call the entry point something different, like "main_plugin", and change the export name with a .def file into "main". Can D do one of these (compile an arbitrary main function or handle a .def file)?

4) While the VST API is a C-API, in C++ you can derive from the AEffect struct to add member functions, which helps in organising (instead of having a bunch of static callback functions floating somewhere). Is this possible in D?

5) A "serious" plugin would need SSE code. I read DMD has it as inline assembler, but this means writing a complete loop in assembler. SSE-intrinsics (that is, specially named functions that compile to SSE-instructions) would be more of a convenience.

Thanks,
Christian

Christian,

This won't help you with D, sorry ...

But I would appreciate hearing about your experience with VST plugin development. I've been working on a "skin/personality" to the open source Audacity audio editor that is specialized for speech rather than music. I would like to learn how to create several plug-ins for Audacity, and hadn't found any examples or tutorials on how to do that (didn't look that hard, however)


"Christian Schüler" <Christian_member@pathlink.com> wrote in message news:d41f9m$24c7$1@digitaldaemon.com...
>
> Been recently thinking about writing a VST plugin in D.
>
> A VST plugin is a .dll for use with Cubase or other music software. It has a specially named C function as entry point:
>

In article <d41f9m$24c7$1@digitaldaemon.com>, Christian Schüler says...
>
>
>Been recently thinking about writing a VST plugin in D.
>
>A VST plugin is a .dll for use with Cubase or other music software. It has a specially named C function as entry point:
>
>AEffect *main( audioMasterCallback audioMaster );
>
>where AEffect is a struct, and audioMasterCallback is a typedef for a function.
>
>

Personally I have no experience in writing plugins for VST, but I used to be an avid Cubase user.  I still have a copy of version 5 floating around here someplace. :)

>1) How do I get these definitions into D? The VST SDK comes with an "aeffect.h" that defines these types and some enums.

You'll first want to convert the headers into D code "headers", that will perform the same task.  The main D page should cover 99% of the things you'll need to do:

http://www.digitalmars.com/d/ctod.html

Just stay faithful to the byte layout of structs, and the intention of the preprocessor directives, and you'll do fine.

If you're linking against a provided .obj or .lib file, make sure they're in OMF format.   You'll know the second it can't link under dmd/optlink. (there is a conversion utility to cover this problem)

>2) How do I build a dll with D?

Again, it's all up on the webpage.

http://www.digitalmars.com/d/dll.html

The first section, "Dlls with a C interface" will apply to your use.

>3) I need to compile a "main" function with different parameters than just (argc, argv). VisualC accepts an arbitrary "main" when compiling a .dll, but GCC does not. Therefore, a common workaround with GCC is to call the entry point something different, like "main_plugin", and change the export name with a .def file into "main". Can D do one of these (compile an arbitrary main function or handle a .def file)?

DMD uses a .def file which supports an "exports" listing.  The syntax supports what you're trying to do here.

http://www.digitalmars.com/ctg/ctgDefFiles.html#exports

>4) While the VST API is a C-API, in C++ you can derive from the AEffect struct to add member functions, which helps in organising (instead of having a bunch of static callback functions floating somewhere). Is this possible in D?

I think you're stuck with structs, callbacks and function pointers.  D does allow methods on structs, but they're non-virtual.  Fortunately, D does have a good function pointer syntax, and placing these inside a struct should help you get the flexibility you crave.

>5) A "serious" plugin would need SSE code. I read DMD has it as inline assembler, but this means writing a complete loop in assembler. SSE-intrinsics (that is, specially named functions that compile to SSE-instructions) would be more of a convenience.

I believe that you are correct that D does not have SSE intrinsic support. You're also correct that the only available workaround in D is to use an asm{} block and code in things manually.  At least D offers you the 'naked' keyword, which should help reduce overhead should you write functions to encapsulate common operations.

Another workaround would be to use a C compiler that has the support you need, and roll a good SSE library that you could import into D.

- EricAnderton at yahoo

Lynn Allan wrote:
> But I would appreciate hearing about your experience with VST plugin
> development

Yeah, me too. I've been interested in tinkering with some DSP algorithms (purely as a learning exercise), and I'd love to read about your experience writing VST plugins.

--BenjiSmith