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Beginner creating VST for project

DSP, Plug-in and Host development discussion.

Moderator: Moderators (Main)

KVRer
 
8 posts since 1 Dec, 2012

Postby pieroni; Wed Dec 05, 2012 5:04 am

Hi,

For a project with University I am trying to create a VST. The starting point is to extend the VstXSynth to have more wave forms (which I have done, whether its correct is a completely different thing haha) as well as an ADSR envelope and simple Delay effect.

In terms of the delay, I have been told I can implement the delay sample code into the vstxsynth, however for whatever reason and whatever I try I can't for the life of me get it to work.

As for the envelope I don't even know where to start. So my question is simple, does anyone have any decent points of reference for a complete beginner to do these kinds of things, or any useful samples explaining the basics?

Much appreciated,
Tom
KVRist
 
222 posts since 16 Dec, 2008, from Boulder CO

Postby David Carpenter Wind Core; Wed Dec 05, 2012 6:49 am

Make it in synthedit export the modules and look at the code. This should give you an idea of how the code works in c+.
The sleeper must awaken.
KVRer
 
8 posts since 1 Dec, 2012

Postby pieroni; Wed Dec 05, 2012 6:54 am

I've seen synthedit before, never used it though. Is it easy to use?

and thankyou.
KVRAF
 
1927 posts since 16 Aug, 2004, from Vienna, Austria
 

Postby arakula; Wed Dec 05, 2012 10:18 am

diggler wrote:Make it in synthedit export the modules and look at the code. This should give you an idea of how the code works in c+.

From earlier experience, my impression was that SynthEdit doesn't emit C++ source code. Am I mistaken? Since when?
"Until you spread your wings, you'll have no idea how far you can walk." Image
KVRian
 
1403 posts since 29 Jan, 2008, from Arboretum Avenue
 

Postby daz.diamond; Wed Dec 05, 2012 2:14 pm

you're not mistaken.
KVRian
 
600 posts since 1 Dec, 2004

Postby MadBrain; Wed Dec 05, 2012 11:50 pm

Yeah I think synthedit tapes a bunch of DLLs together so all the code is already compiled.

Some tips:

Delay: Use a "circular buffer" (essentially an array with the read/write pointers skipping back to the start once the pass the end). Make sure you zero your memory in the constructor.

Envelope: Just code a class that outputs a value that increases/decreases over time (depending on which shape you want).

If you're having a hard time still, you might want to improve your knowledge of C++ too.
User avatar
KVRAF
 
2850 posts since 22 Jul, 2006, from Melbourne, Australia
  

Postby nix808; Thu Dec 06, 2012 12:21 am

with the envelope,
you just want to multiply the oscillators stream with how loud u want it to be.
Release is problematic,
I dunno how it's done really.
But essentially just make an amplitude curve that is MIDI dependant and multiply with stream.
With delay, write to memory and subtract your number of samples which is length
when u read it.
There was some other thing that might be neccessary to avoid clicks. It involved the counting at the end of the buffer.
If your delay is clicking, let me know and I will look what I did to mine.
All success!

edit-also with the delay you need to feedback, for echo
KVRer
 
8 posts since 1 Dec, 2012

Postby pieroni; Fri Dec 07, 2012 5:10 am

Brilliant, thanks for all the feedback. Appreciate it.

So far, I've implemented a lot of the code for Delay, taking into account the frequency amount (as mentioned above). I'm struggling a bit in terms of what needs to go in the process function. The ADelay sample appears to implement the process within the While Loop, am I correct in thinking this?
KVRist
 
222 posts since 16 Dec, 2008, from Boulder CO

Postby David Carpenter Wind Core; Sun Dec 16, 2012 1:20 pm

You can export C++ code from synthedit modules. Also you can write new modules in C++.

To export a module into c++ source code right click and select build code skeleton.

This of course is written for synthedit but you could see how to write it for a different app by looking at the source to get an idea.
The sleeper must awaken.
User avatar
KVRist
 
150 posts since 30 Apr, 2006, from PA->FL->PA->???
 

Postby random_id; Sun Dec 16, 2012 4:42 pm

pieroni wrote:The ADelay sample appears to implement the process within the While Loop, am I correct in thinking this?


Yes, the audio host passes a chunk of samples to the plugin to process. The While Loop in the example is where the sound is actually processed. The rest of the code is basically used to setup the controls (e.g., what happens when you click on a slider to increase/decrease the value). For the most part, you want to keep things as efficient as possible within the loop.
KVRian
 
1403 posts since 29 Jan, 2008, from Arboretum Avenue
 

Postby daz.diamond; Mon Dec 17, 2012 1:27 am

diggler wrote:To export a module into c++ source code right click and select build code skeleton.


all this does is give the code for a blank module with the pins as per the module you selected - no code is generated for the actual functionality. it is meant as a tool to help 'port' sems from sdk2 to sdk3 ...

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