Any plans to implement a VST host in rust?

[ZECTBynmo]

I would LOVE to see that happen!

[overdrivenpotato]

This is definitely doable, it would essentially involve wrapping a dynamically loaded library (the plugin) in a some type of struct that handles passing VST opcodes between the host rust program and the plugin.

If you (or anybody else) wants to try this, it'd probably look something like this:

struct Plugin {...}
impl Plugin {
    pub fn load(...) -> Plugin {...}

    // For example    
    pub fn init(&mut self) {
        // Send OpCode::Initialize to loaded library via vst2::api::AEffect::dispatcher
        let opcode = vst2::plugin::OpCode::Initialize.into();
        self.effect.dispatcher(self.effect_ptr, opcode, 0, 0, ptr::null_mut(), 0.0);
    }

    // Rest of VST opcodes ...
}

I don't have any plans at the moment to support this but if I have some free time I might be able to cook up a prototype

[ZECTBynmo]

What are your thoughts about the process of showing the editors of hosted plugins from the DAW? Do you think it's possible? Easy? What would your instincts be about the first steps?

[overdrivenpotato]

I think it'd be actually fairly simple as the VST API only really requires a window pointer to be passed to the plugin. It would have to be a platform specific window pointer though, e.g. X11, WinAPI or Carbon on OS X (optionally Cocoa if the plugin and host both support it). Pretty sure this library would only have to open the platform specific editor window and pass it to the plugin for that to work.

It gets a little bit more complex if you're building a plugin, as to actually interact with the editor window you need to use platform-specific APIs. That is a bit of a pain especially in rust, so there could potentially be another library built off this one that handles the platform specific stuff

[ZECTBynmo]

I'm actually only interested in the VST host part, so that sounds awesome! Any chance you might take a swing at it? I'd be happy to donate a few bucks!

[overdrivenpotato]

Yeah for sure, if I get some time this week/next week I'll try and get a working implementation

[ZECTBynmo]

Hey @overdrivenpotato if you can get a rust VST host working that can show client VST GUIs and process audio, I'll send you $50 via PayPal

[overdrivenpotato]

@ZECTBynmo any example plugins you'd like to load?

[ZECTBynmo]

@overdrivenpotato how about:
iZotope Ozone 5 (the most important one - and likely the most difficult)
NI Omnisphere
Guitar Rig 5

[overdrivenpotato]

Alright that seems doable, I'll update you when I get something running

[ZECTBynmo]

Awesome! Looking forward to it

[overdrivenpotato]

Just a quick update: most of the VST-related programming for this to work is finished, and I have been able to load and play around with Ozone 5. The only remaining problem is passing a window pointer to the plugin. I've gotten this to work via a forked version of glutin but I'm currently just writing a simpler stripped down window library to give more flexible options. It might just be a submodule in rust-vst2 as it is fairly specific but I'm debating just creating a new repository and pushing it to crates.io.

[ZECTBynmo]

Wow that is so cool @overdrivenpotato!!! I'm super excited to see it!

[Boscop]

Hey @overdrivenpotato, I'm also very interested in a VST host in Rust!
Which window library are you using?
Are you using https://github.com/RustAudio/dsp-chain for the processing?

[overdrivenpotato]

I was using glutin initially as the window library, but with most of the functionality removed and with modifications to allow plugins to properly draw. I'm currently just writing a really small module to do exactly what glutin did but tailored to the VSTAPI.
Processing is up to the plugin to implement as custom functionality so at the moment dsp-chain would be more useful for plugin developers.

[ZECTBynmo]

@overdrivenpotato do I owe you $50 yet? :)