add "bring your own gui" example plugins

plugins/examples/byo_gui_gl/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "byo_gui_gl"
+version = "0.1.0"
+edition = "2021"
+authors = ["Billy Messenger <60663878+BillyDM@users.noreply.github.com>"]
+license = "ISC"
+
+description = "A simple example plugin with a raw OpenGL context for rendering"
+
+[lib]
+# The `lib` artifact is needed for the standalone target
+crate-type = ["cdylib", "lib"]
+
+[dependencies]
+nih_plug = { path = "../../../", features = ["assert_process_allocs", "standalone"] }
+baseview = { git = "https://github.com/RustAudio/baseview.git", rev = "9a0b42c09d712777b2edb4c5e0cb6baf21e988f0", features = ["opengl"] }
+raw-window-handle = "0.5"
+glow = "0.16"
+crossbeam = "0.8"
+atomic_float = "0.1"
+# To make the state persistable
+serde = { version = "1.0", features = ["derive"] }

plugins/examples/byo_gui_gl/src/lib.rs

@@ -0,0 +1,553 @@
+//! This plugin demonstrates how to "bring your own GUI toolkit" using a raw OpenGL context.
+
+use baseview::{gl::GlConfig, WindowHandle, WindowOpenOptions, WindowScalePolicy};
+use crossbeam::atomic::AtomicCell;
+use nih_plug::params::persist::PersistentField;
+use nih_plug::prelude::*;
+use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
+use serde::{Deserialize, Serialize};
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
+
+/// The time it takes for the peak meter to decay by 12 dB after switching to complete silence.
+const PEAK_METER_DECAY_MS: f64 = 150.0;
+
+pub struct CustomGlWindow {
+    gui_context: Arc<dyn GuiContext>,
+    gl: Arc<glow::Context>,
+
+    vertex_array: glow::NativeVertexArray,
+    program: glow::NativeProgram,
+
+    #[allow(unused)]
+    params: Arc<MyPluginParams>,
+    #[allow(unused)]
+    peak_meter: Arc<AtomicF32>,
+}
+
+impl Drop for CustomGlWindow {
+    fn drop(&mut self) {
+        use glow::HasContext as _;
+
+        unsafe {
+            self.gl.delete_program(self.program);
+            self.gl.delete_vertex_array(self.vertex_array);
+        }
+    }
+}
+
+impl CustomGlWindow {
+    fn new(
+        window: &mut baseview::Window<'_>,
+        gui_context: Arc<dyn GuiContext>,
+        params: Arc<MyPluginParams>,
+        peak_meter: Arc<AtomicF32>,
+        _scaling_factor: f32,
+    ) -> Self {
+        use glow::HasContext as _;
+
+        // TODO: Return an error instead of panicking once baseview gets thats
+        // ability.
+        let gl_context = window
+            .gl_context()
+            .expect("failed to get baseview gl context");
+
+        let (gl, vertex_array, program) = unsafe {
+            gl_context.make_current();
+
+            #[allow(clippy::arc_with_non_send_sync)]
+            let gl = Arc::new(glow::Context::from_loader_function(|s| {
+                gl_context.get_proc_address(s)
+            }));
+
+            let vertex_array = gl
+                .create_vertex_array()
+                .expect("Cannot create vertex array");
+            gl.bind_vertex_array(Some(vertex_array));
+
+            let program = gl.create_program().expect("Cannot create program");
+
+            let (vertex_shader_source, fragment_shader_source) = (
+                r#"const vec2 verts[3] = vec2[3](
+                    vec2(0.5f, 1.0f),
+                    vec2(0.0f, 0.0f),
+                    vec2(1.0f, 0.0f)
+                );
+                out vec2 vert;
+                void main() {
+                    vert = verts[gl_VertexID];
+                    gl_Position = vec4(vert - 0.5, 0.0, 1.0);
+                }"#,
+                r#"precision mediump float;
+                in vec2 vert;
+                out vec4 color;
+                void main() {
+                    color = vec4(vert, 0.5, 1.0);
+                }"#,
+            );
+
+            let shader_sources = [
+                (glow::VERTEX_SHADER, vertex_shader_source),
+                (glow::FRAGMENT_SHADER, fragment_shader_source),
+            ];
+
+            let mut shaders = Vec::with_capacity(shader_sources.len());
+
+            for (shader_type, shader_source) in shader_sources.iter() {
+                let shader = gl
+                    .create_shader(*shader_type)
+                    .expect("Cannot create shader");
+                gl.shader_source(shader, &format!("{}\n{}", "#version 130", shader_source));
+                gl.compile_shader(shader);
+                if !gl.get_shader_compile_status(shader) {
+                    panic!("{}", gl.get_shader_info_log(shader));
+                }
+                gl.attach_shader(program, shader);
+                shaders.push(shader);
+            }
+
+            gl.link_program(program);
+            if !gl.get_program_link_status(program) {
+                panic!("{}", gl.get_program_info_log(program));
+            }
+
+            for shader in shaders {
+                gl.detach_shader(program, shader);
+                gl.delete_shader(shader);
+            }
+
+            gl.use_program(Some(program));
+
+            gl_context.make_not_current();
+
+            (gl, vertex_array, program)
+        };
+
+        Self {
+            gui_context,
+            gl,
+            vertex_array,
+            program,
+            params,
+            peak_meter,
+        }
+    }
+}
+
+impl baseview::WindowHandler for CustomGlWindow {
+    fn on_frame(&mut self, window: &mut baseview::Window) {
+        use glow::HasContext as _;
+        // Do rendering here.
+
+        let (_width, _height) = self.params.editor_state.size();
+
+        let gl_context = window
+            .gl_context()
+            .expect("failed to get baseview gl context");
+
+        unsafe {
+            gl_context.make_current();
+
+            self.gl.clear_color(0.05, 0.05, 0.05, 1.0);
+            self.gl.clear(glow::COLOR_BUFFER_BIT);
+
+            self.gl.draw_arrays(glow::TRIANGLES, 0, 3);
+
+            gl_context.swap_buffers();
+            gl_context.make_not_current();
+        }
+    }
+
+    fn on_event(
+        &mut self,
+        _window: &mut baseview::Window,
+        event: baseview::Event,
+    ) -> baseview::EventStatus {
+        // Use this to set parameter values.
+        let _param_setter = ParamSetter::new(self.gui_context.as_ref());
+
+        match &event {
+            // Do event processing here.
+            baseview::Event::Window(event) => match event {
+                baseview::WindowEvent::Resized(window_info) => {
+                    self.params.editor_state.size.store((
+                        window_info.logical_size().width.round() as u32,
+                        window_info.logical_size().height.round() as u32,
+                    ));
+                }
+                _ => {}
+            },
+            _ => {}
+        }
+
+        baseview::EventStatus::Captured
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct CustomGlEditorState {
+    /// The window's size in logical pixels before applying `scale_factor`.
+    #[serde(with = "nih_plug::params::persist::serialize_atomic_cell")]
+    size: AtomicCell<(u32, u32)>,
+    /// Whether the editor's window is currently open.
+    #[serde(skip)]
+    open: AtomicBool,
+}
+
+impl CustomGlEditorState {
+    pub fn from_size(size: (u32, u32)) -> Arc<Self> {
+        Arc::new(Self {
+            size: AtomicCell::new(size),
+            open: AtomicBool::new(false),
+        })
+    }
+
+    /// Returns a `(width, height)` pair for the current size of the GUI in logical pixels.
+    pub fn size(&self) -> (u32, u32) {
+        self.size.load()
+    }
+
+    /// Whether the GUI is currently visible.
+    // Called `is_open()` instead of `open()` to avoid the ambiguity.
+    pub fn is_open(&self) -> bool {
+        self.open.load(Ordering::Acquire)
+    }
+}
+
+impl<'a> PersistentField<'a, CustomGlEditorState> for Arc<CustomGlEditorState> {
+    fn set(&self, new_value: CustomGlEditorState) {
+        self.size.store(new_value.size.load());
+    }
+
+    fn map<F, R>(&self, f: F) -> R
+    where
+        F: Fn(&CustomGlEditorState) -> R,
+    {
+        f(self)
+    }
+}
+
+pub struct CustomGlEditor {
+    params: Arc<MyPluginParams>,
+    peak_meter: Arc<AtomicF32>,
+
+    /// The scaling factor reported by the host, if any. On macOS this will never be set and we
+    /// should use the system scaling factor instead.
+    scaling_factor: AtomicCell<Option<f32>>,
+}
+
+impl Editor for CustomGlEditor {
+    fn spawn(
+        &self,
+        parent: ParentWindowHandle,
+        context: Arc<dyn GuiContext>,
+    ) -> Box<dyn std::any::Any + Send> {
+        let (unscaled_width, unscaled_height) = self.params.editor_state.size();
+        let scaling_factor = self.scaling_factor.load();
+
+        let gui_context = Arc::clone(&context);
+
+        let params = Arc::clone(&self.params);
+        let peak_meter = Arc::clone(&self.peak_meter);
+
+        let window = baseview::Window::open_parented(
+            &ParentWindowHandleAdapter(parent),
+            WindowOpenOptions {
+                title: String::from("OpenGL Window"),
+                // Baseview should be doing the DPI scaling for us
+                size: baseview::Size::new(unscaled_width as f64, unscaled_height as f64),
+                // NOTE: For some reason passing 1.0 here causes the UI to be scaled on macOS but
+                //       not the mouse events.
+                scale: scaling_factor
+                    .map(|factor| WindowScalePolicy::ScaleFactor(factor as f64))
+                    .unwrap_or(WindowScalePolicy::SystemScaleFactor),
+
+                gl_config: Some(GlConfig {
+                    version: (3, 2),
+                    red_bits: 8,
+                    blue_bits: 8,
+                    green_bits: 8,
+                    alpha_bits: 8,
+                    depth_bits: 24,
+                    stencil_bits: 8,
+                    samples: None,
+                    srgb: true,
+                    double_buffer: true,
+                    vsync: false,
+                    ..Default::default()
+                }),
+            },
+            move |window: &mut baseview::Window<'_>| -> CustomGlWindow {
+                CustomGlWindow::new(
+                    window,
+                    gui_context,
+                    params,
+                    peak_meter,
+                    scaling_factor.unwrap_or(1.0),
+                )
+            },
+        );
+
+        self.params.editor_state.open.store(true, Ordering::Release);
+        Box::new(CustomGlEditorHandle {
+            state: self.params.editor_state.clone(),
+            window,
+        })
+    }
+
+    fn size(&self) -> (u32, u32) {
+        self.params.editor_state.size()
+    }
+
+    fn set_scale_factor(&self, factor: f32) -> bool {
+        // If the editor is currently open then the host must not change the current HiDPI scale as
+        // we don't have a way to handle that. Ableton Live does this.
+        if self.params.editor_state.is_open() {
+            return false;
+        }
+
+        self.scaling_factor.store(Some(factor));
+        true
+    }
+
+    fn param_value_changed(&self, _id: &str, _normalized_value: f32) {
+        // As mentioned above, for now we'll always force a redraw to allow meter widgets to work
+        // correctly. In the future we can use an `Arc<AtomicBool>` and only force a redraw when
+        // that boolean is set.
+    }
+
+    fn param_modulation_changed(&self, _id: &str, _modulation_offset: f32) {}
+
+    fn param_values_changed(&self) {
+        // Same
+    }
+}
+
+/// The window handle used for [`EguiEditor`].
+struct CustomGlEditorHandle {
+    state: Arc<CustomGlEditorState>,
+    window: WindowHandle,
+}
+
+/// The window handle enum stored within 'WindowHandle' contains raw pointers. Is there a way around
+/// having this requirement?
+unsafe impl Send for CustomGlEditorHandle {}
+
+impl Drop for CustomGlEditorHandle {
+    fn drop(&mut self) {
+        self.state.open.store(false, Ordering::Release);
+        // XXX: This should automatically happen when the handle gets dropped, but apparently not
+        self.window.close();
+    }
+}
+
+/// This version of `baseview` uses a different version of `raw_window_handle than NIH-plug, so we
+/// need to adapt it ourselves.
+struct ParentWindowHandleAdapter(nih_plug::editor::ParentWindowHandle);
+
+unsafe impl HasRawWindowHandle for ParentWindowHandleAdapter {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        match self.0 {
+            ParentWindowHandle::X11Window(window) => {
+                let mut handle = raw_window_handle::XcbWindowHandle::empty();
+                handle.window = window;
+                RawWindowHandle::Xcb(handle)
+            }
+            ParentWindowHandle::AppKitNsView(ns_view) => {
+                let mut handle = raw_window_handle::AppKitWindowHandle::empty();
+                handle.ns_view = ns_view;
+                RawWindowHandle::AppKit(handle)
+            }
+            ParentWindowHandle::Win32Hwnd(hwnd) => {
+                let mut handle = raw_window_handle::Win32WindowHandle::empty();
+                handle.hwnd = hwnd;
+                RawWindowHandle::Win32(handle)
+            }
+        }
+    }
+}
+
+/// This is mostly identical to the gain example, minus some fluff, and with a GUI.
+pub struct MyPlugin {
+    params: Arc<MyPluginParams>,
+
+    /// Needed to normalize the peak meter's response based on the sample rate.
+    peak_meter_decay_weight: f32,
+    /// The current data for the peak meter. This is stored as an [`Arc`] so we can share it between
+    /// the GUI and the audio processing parts. If you have more state to share, then it's a good
+    /// idea to put all of that in a struct behind a single `Arc`.
+    ///
+    /// This is stored as voltage gain.
+    peak_meter: Arc<AtomicF32>,
+}
+
+#[derive(Params)]
+pub struct MyPluginParams {
+    /// The editor state, saved together with the parameter state so the custom scaling can be
+    /// restored.
+    #[persist = "editor-state"]
+    editor_state: Arc<CustomGlEditorState>,
+
+    #[id = "gain"]
+    pub gain: FloatParam,
+
+    #[id = "foobar"]
+    pub some_int: IntParam,
+}
+
+impl Default for MyPlugin {
+    fn default() -> Self {
+        Self {
+            params: Arc::new(MyPluginParams::default()),
+
+            peak_meter_decay_weight: 1.0,
+            peak_meter: Arc::new(AtomicF32::new(util::MINUS_INFINITY_DB)),
+        }
+    }
+}
+
+impl Default for MyPluginParams {
+    fn default() -> Self {
+        Self {
+            editor_state: CustomGlEditorState::from_size((400, 300)),
+
+            // See the main gain example for more details
+            gain: FloatParam::new(
+                "Gain",
+                util::db_to_gain(0.0),
+                FloatRange::Skewed {
+                    min: util::db_to_gain(-30.0),
+                    max: util::db_to_gain(30.0),
+                    factor: FloatRange::gain_skew_factor(-30.0, 30.0),
+                },
+            )
+            .with_smoother(SmoothingStyle::Logarithmic(50.0))
+            .with_unit(" dB")
+            .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
+            .with_string_to_value(formatters::s2v_f32_gain_to_db()),
+            some_int: IntParam::new("Something", 3, IntRange::Linear { min: 0, max: 3 }),
+        }
+    }
+}
+
+impl Plugin for MyPlugin {
+    const NAME: &'static str = "BYO GUI Example (OpenGL)";
+    const VENDOR: &'static str = "Moist Plugins GmbH";
+    const URL: &'static str = "https://youtu.be/dQw4w9WgXcQ";
+    const EMAIL: &'static str = "info@example.com";
+
+    const VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+    const AUDIO_IO_LAYOUTS: &'static [AudioIOLayout] = &[
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(2),
+            main_output_channels: NonZeroU32::new(2),
+            ..AudioIOLayout::const_default()
+        },
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(1),
+            main_output_channels: NonZeroU32::new(1),
+            ..AudioIOLayout::const_default()
+        },
+    ];
+
+    const SAMPLE_ACCURATE_AUTOMATION: bool = true;
+
+    type SysExMessage = ();
+    type BackgroundTask = ();
+
+    fn params(&self) -> Arc<dyn Params> {
+        self.params.clone()
+    }
+
+    fn editor(&mut self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
+        Some(Box::new(CustomGlEditor {
+            params: Arc::clone(&self.params),
+            peak_meter: Arc::clone(&self.peak_meter),
+
+            // TODO: We can't get the size of the window when baseview does its own scaling, so if the
+            //       host does not set a scale factor on Windows or Linux we should just use a factor of
+            //       1. That may make the GUI tiny but it also prevents it from getting cut off.
+            #[cfg(target_os = "macos")]
+            scaling_factor: AtomicCell::new(None),
+            #[cfg(not(target_os = "macos"))]
+            scaling_factor: AtomicCell::new(Some(1.0)),
+        }))
+    }
+
+    fn initialize(
+        &mut self,
+        _audio_io_layout: &AudioIOLayout,
+        buffer_config: &BufferConfig,
+        _context: &mut impl InitContext<Self>,
+    ) -> bool {
+        // After `PEAK_METER_DECAY_MS` milliseconds of pure silence, the peak meter's value should
+        // have dropped by 12 dB
+        self.peak_meter_decay_weight = 0.25f64
+            .powf((buffer_config.sample_rate as f64 * PEAK_METER_DECAY_MS / 1000.0).recip())
+            as f32;
+
+        true
+    }
+
+    fn process(
+        &mut self,
+        buffer: &mut Buffer,
+        _aux: &mut AuxiliaryBuffers,
+        _context: &mut impl ProcessContext<Self>,
+    ) -> ProcessStatus {
+        for channel_samples in buffer.iter_samples() {
+            let mut amplitude = 0.0;
+            let num_samples = channel_samples.len();
+
+            let gain = self.params.gain.smoothed.next();
+            for sample in channel_samples {
+                *sample *= gain;
+                amplitude += *sample;
+            }
+
+            // To save resources, a plugin can (and probably should!) only perform expensive
+            // calculations that are only displayed on the GUI while the GUI is open
+            if self.params.editor_state.is_open() {
+                amplitude = (amplitude / num_samples as f32).abs();
+                let current_peak_meter = self.peak_meter.load(std::sync::atomic::Ordering::Relaxed);
+                let new_peak_meter = if amplitude > current_peak_meter {
+                    amplitude
+                } else {
+                    current_peak_meter * self.peak_meter_decay_weight
+                        + amplitude * (1.0 - self.peak_meter_decay_weight)
+                };
+
+                self.peak_meter
+                    .store(new_peak_meter, std::sync::atomic::Ordering::Relaxed)
+            }
+        }
+
+        ProcessStatus::Normal
+    }
+}
+
+impl ClapPlugin for MyPlugin {
+    const CLAP_ID: &'static str = "com.moist-plugins-gmbh.byo-gui-gl";
+    const CLAP_DESCRIPTION: Option<&'static str> =
+        Some("A simple example plugin with a raw OpenGL context for rendering");
+    const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
+    const CLAP_SUPPORT_URL: Option<&'static str> = None;
+    const CLAP_FEATURES: &'static [ClapFeature] = &[
+        ClapFeature::AudioEffect,
+        ClapFeature::Stereo,
+        ClapFeature::Mono,
+        ClapFeature::Utility,
+    ];
+}
+
+impl Vst3Plugin for MyPlugin {
+    const VST3_CLASS_ID: [u8; 16] = *b"ByoGuiOpenGLWooo";
+    const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] =
+        &[Vst3SubCategory::Fx, Vst3SubCategory::Tools];
+}
+
+nih_export_clap!(MyPlugin);
+nih_export_vst3!(MyPlugin);

plugins/examples/byo_gui_gl/src/main.rs

@@ -0,0 +1,7 @@
+use nih_plug::prelude::*;
+
+use byo_gui_gl::MyPlugin;
+
+fn main() {
+    nih_export_standalone::<MyPlugin>();
+}

plugins/examples/byo_gui_softbuffer/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "byo_gui_softbuffer"
+version = "0.1.0"
+edition = "2021"
+authors = ["Billy Messenger <60663878+BillyDM@users.noreply.github.com>"]
+license = "ISC"
+
+description = "A simple example plugin with a raw Softbuffer context for rendering"
+
+[lib]
+# The `lib` artifact is needed for the standalone target
+crate-type = ["cdylib", "lib"]
+
+[dependencies]
+nih_plug = { path = "../../../", features = ["assert_process_allocs", "standalone"] }
+baseview = { git = "https://github.com/RustAudio/baseview.git", rev = "9a0b42c09d712777b2edb4c5e0cb6baf21e988f0" }
+softbuffer = { version = "0.4.6", default-features = false, features = ["kms", "x11"]}
+raw-window-handle = "0.5"
+raw-window-handle-06 = { package = "raw-window-handle", version = "0.6" }
+crossbeam = "0.8"
+atomic_float = "0.1"
+# To make the state persistable
+serde = { version = "1.0", features = ["derive"] }

plugins/examples/byo_gui_softbuffer/src/lib.rs

@@ -0,0 +1,585 @@
+//! This plugin demonstrates how to "bring your own GUI toolkit" using a raw Softbuffer rendering context.
+
+use baseview::{WindowHandle, WindowOpenOptions, WindowScalePolicy};
+use crossbeam::atomic::AtomicCell;
+use nih_plug::params::persist::PersistentField;
+use nih_plug::prelude::*;
+use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
+use serde::{Deserialize, Serialize};
+use std::{
+    num::NonZeroIsize,
+    ptr::NonNull,
+    sync::{
+        atomic::{AtomicBool, Ordering},
+        Arc,
+    },
+};
+
+/// The time it takes for the peak meter to decay by 12 dB after switching to complete silence.
+const PEAK_METER_DECAY_MS: f64 = 150.0;
+
+pub struct CustomSoftbufferWindow {
+    gui_context: Arc<dyn GuiContext>,
+
+    _sb_context: softbuffer::Context<SoftbufferWindowHandleAdapter>,
+    sb_surface: softbuffer::Surface<SoftbufferWindowHandleAdapter, SoftbufferWindowHandleAdapter>,
+
+    physical_width: u32,
+    physical_height: u32,
+
+    #[allow(unused)]
+    params: Arc<MyPluginParams>,
+    #[allow(unused)]
+    peak_meter: Arc<AtomicF32>,
+}
+
+impl CustomSoftbufferWindow {
+    fn new(
+        window: &mut baseview::Window<'_>,
+        gui_context: Arc<dyn GuiContext>,
+        params: Arc<MyPluginParams>,
+        peak_meter: Arc<AtomicF32>,
+        scaling_factor: f32,
+    ) -> Self {
+        let (unscaled_width, unscaled_height) = params.editor_state.size();
+        let physical_width = (unscaled_width as f64 * scaling_factor as f64).round() as u32;
+        let physical_height = (unscaled_height as f64 * scaling_factor as f64).round() as u32;
+
+        let target = baseview_window_to_surface_target(window);
+
+        let sb_context =
+            softbuffer::Context::new(target.clone()).expect("could not get softbuffer context");
+        let mut sb_surface = softbuffer::Surface::new(&sb_context, target)
+            .expect("could not create softbuffer surface");
+
+        sb_surface
+            .resize(
+                NonZeroU32::new(physical_width).unwrap(),
+                NonZeroU32::new(physical_height).unwrap(),
+            )
+            .unwrap();
+
+        Self {
+            gui_context,
+            _sb_context: sb_context,
+            sb_surface,
+            physical_width,
+            physical_height,
+            params,
+            peak_meter,
+        }
+    }
+}
+
+impl baseview::WindowHandler for CustomSoftbufferWindow {
+    fn on_frame(&mut self, _window: &mut baseview::Window) {
+        // Do rendering here.
+
+        let mut buffer = self.sb_surface.buffer_mut().unwrap();
+        for y in 0..self.physical_height {
+            for x in 0..self.physical_width {
+                let red = x % 255;
+                let green = y % 255;
+                let blue = (x * y) % 255;
+                let index = y as usize * self.physical_width as usize + x as usize;
+                buffer[index] = blue | (green << 8) | (red << 16);
+            }
+        }
+
+        buffer.present().unwrap();
+    }
+
+    fn on_event(
+        &mut self,
+        _window: &mut baseview::Window,
+        event: baseview::Event,
+    ) -> baseview::EventStatus {
+        // Use this to set parameter values.
+        let _param_setter = ParamSetter::new(self.gui_context.as_ref());
+
+        match &event {
+            // Do event processing here.
+            baseview::Event::Window(event) => match event {
+                baseview::WindowEvent::Resized(window_info) => {
+                    self.params.editor_state.size.store((
+                        window_info.logical_size().width.round() as u32,
+                        window_info.logical_size().height.round() as u32,
+                    ));
+
+                    self.physical_width = window_info.physical_size().width;
+                    self.physical_height = window_info.physical_size().height;
+
+                    self.sb_surface
+                        .resize(
+                            NonZeroU32::new(self.physical_width).unwrap(),
+                            NonZeroU32::new(self.physical_height).unwrap(),
+                        )
+                        .unwrap();
+                }
+                _ => {}
+            },
+            _ => {}
+        }
+
+        baseview::EventStatus::Captured
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct CustomSoftbufferEditorState {
+    /// The window's size in logical pixels before applying `scale_factor`.
+    #[serde(with = "nih_plug::params::persist::serialize_atomic_cell")]
+    size: AtomicCell<(u32, u32)>,
+    /// Whether the editor's window is currently open.
+    #[serde(skip)]
+    open: AtomicBool,
+}
+
+impl CustomSoftbufferEditorState {
+    pub fn from_size(size: (u32, u32)) -> Arc<Self> {
+        Arc::new(Self {
+            size: AtomicCell::new(size),
+            open: AtomicBool::new(false),
+        })
+    }
+
+    /// Returns a `(width, height)` pair for the current size of the GUI in logical pixels.
+    pub fn size(&self) -> (u32, u32) {
+        self.size.load()
+    }
+
+    /// Whether the GUI is currently visible.
+    // Called `is_open()` instead of `open()` to avoid the ambiguity.
+    pub fn is_open(&self) -> bool {
+        self.open.load(Ordering::Acquire)
+    }
+}
+
+impl<'a> PersistentField<'a, CustomSoftbufferEditorState> for Arc<CustomSoftbufferEditorState> {
+    fn set(&self, new_value: CustomSoftbufferEditorState) {
+        self.size.store(new_value.size.load());
+    }
+
+    fn map<F, R>(&self, f: F) -> R
+    where
+        F: Fn(&CustomSoftbufferEditorState) -> R,
+    {
+        f(self)
+    }
+}
+
+pub struct CustomSoftbufferEditor {
+    params: Arc<MyPluginParams>,
+    peak_meter: Arc<AtomicF32>,
+
+    /// The scaling factor reported by the host, if any. On macOS this will never be set and we
+    /// should use the system scaling factor instead.
+    scaling_factor: AtomicCell<Option<f32>>,
+}
+
+impl Editor for CustomSoftbufferEditor {
+    fn spawn(
+        &self,
+        parent: ParentWindowHandle,
+        context: Arc<dyn GuiContext>,
+    ) -> Box<dyn std::any::Any + Send> {
+        let (unscaled_width, unscaled_height) = self.params.editor_state.size();
+        let scaling_factor = self.scaling_factor.load();
+
+        let gui_context = Arc::clone(&context);
+
+        let params = Arc::clone(&self.params);
+        let peak_meter = Arc::clone(&self.peak_meter);
+
+        let window = baseview::Window::open_parented(
+            &ParentWindowHandleAdapter(parent),
+            WindowOpenOptions {
+                title: String::from("Softbuffer Window"),
+                // Baseview should be doing the DPI scaling for us
+                size: baseview::Size::new(unscaled_width as f64, unscaled_height as f64),
+                // NOTE: For some reason passing 1.0 here causes the UI to be scaled on macOS but
+                //       not the mouse events.
+                scale: scaling_factor
+                    .map(|factor| WindowScalePolicy::ScaleFactor(factor as f64))
+                    .unwrap_or(WindowScalePolicy::SystemScaleFactor),
+            },
+            move |window: &mut baseview::Window<'_>| -> CustomSoftbufferWindow {
+                CustomSoftbufferWindow::new(
+                    window,
+                    gui_context,
+                    params,
+                    peak_meter,
+                    scaling_factor.unwrap_or(1.0),
+                )
+            },
+        );
+
+        self.params.editor_state.open.store(true, Ordering::Release);
+        Box::new(CustomSoftbufferEditorHandle {
+            state: self.params.editor_state.clone(),
+            window,
+        })
+    }
+
+    fn size(&self) -> (u32, u32) {
+        self.params.editor_state.size()
+    }
+
+    fn set_scale_factor(&self, factor: f32) -> bool {
+        // If the editor is currently open then the host must not change the current HiDPI scale as
+        // we don't have a way to handle that. Ableton Live does this.
+        if self.params.editor_state.is_open() {
+            return false;
+        }
+
+        self.scaling_factor.store(Some(factor));
+        true
+    }
+
+    fn param_value_changed(&self, _id: &str, _normalized_value: f32) {
+        // As mentioned above, for now we'll always force a redraw to allow meter widgets to work
+        // correctly. In the future we can use an `Arc<AtomicBool>` and only force a redraw when
+        // that boolean is set.
+    }
+
+    fn param_modulation_changed(&self, _id: &str, _modulation_offset: f32) {}
+
+    fn param_values_changed(&self) {
+        // Same
+    }
+}
+
+/// The window handle used for [`EguiEditor`].
+struct CustomSoftbufferEditorHandle {
+    state: Arc<CustomSoftbufferEditorState>,
+    window: WindowHandle,
+}
+
+/// The window handle enum stored within 'WindowHandle' contains raw pointers. Is there a way around
+/// having this requirement?
+unsafe impl Send for CustomSoftbufferEditorHandle {}
+
+impl Drop for CustomSoftbufferEditorHandle {
+    fn drop(&mut self) {
+        self.state.open.store(false, Ordering::Release);
+        // XXX: This should automatically happen when the handle gets dropped, but apparently not
+        self.window.close();
+    }
+}
+
+/// This version of `baseview` uses a different version of `raw_window_handle than NIH-plug, so we
+/// need to adapt it ourselves.
+struct ParentWindowHandleAdapter(nih_plug::editor::ParentWindowHandle);
+
+unsafe impl HasRawWindowHandle for ParentWindowHandleAdapter {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        match self.0 {
+            ParentWindowHandle::X11Window(window) => {
+                let mut handle = raw_window_handle::XcbWindowHandle::empty();
+                handle.window = window;
+                RawWindowHandle::Xcb(handle)
+            }
+            ParentWindowHandle::AppKitNsView(ns_view) => {
+                let mut handle = raw_window_handle::AppKitWindowHandle::empty();
+                handle.ns_view = ns_view;
+                RawWindowHandle::AppKit(handle)
+            }
+            ParentWindowHandle::Win32Hwnd(hwnd) => {
+                let mut handle = raw_window_handle::Win32WindowHandle::empty();
+                handle.hwnd = hwnd;
+                RawWindowHandle::Win32(handle)
+            }
+        }
+    }
+}
+
+/// Softbuffer uses raw_window_handle v6, but baseview uses raw_window_handle v5, so we need to
+/// adapt it ourselves.
+#[derive(Clone)]
+struct SoftbufferWindowHandleAdapter {
+    raw_display_handle: raw_window_handle_06::RawDisplayHandle,
+    raw_window_handle: raw_window_handle_06::RawWindowHandle,
+}
+
+impl raw_window_handle_06::HasDisplayHandle for SoftbufferWindowHandleAdapter {
+    fn display_handle(
+        &self,
+    ) -> Result<raw_window_handle_06::DisplayHandle<'_>, raw_window_handle_06::HandleError> {
+        unsafe {
+            Ok(raw_window_handle_06::DisplayHandle::borrow_raw(
+                self.raw_display_handle,
+            ))
+        }
+    }
+}
+
+impl raw_window_handle_06::HasWindowHandle for SoftbufferWindowHandleAdapter {
+    fn window_handle(
+        &self,
+    ) -> Result<raw_window_handle_06::WindowHandle<'_>, raw_window_handle_06::HandleError> {
+        unsafe {
+            Ok(raw_window_handle_06::WindowHandle::borrow_raw(
+                self.raw_window_handle,
+            ))
+        }
+    }
+}
+
+fn baseview_window_to_surface_target(
+    window: &baseview::Window<'_>,
+) -> SoftbufferWindowHandleAdapter {
+    use raw_window_handle::{HasRawDisplayHandle, HasRawWindowHandle};
+
+    let raw_display_handle = window.raw_display_handle();
+    let raw_window_handle = window.raw_window_handle();
+
+    SoftbufferWindowHandleAdapter {
+        raw_display_handle: match raw_display_handle {
+            raw_window_handle::RawDisplayHandle::AppKit(_) => {
+                raw_window_handle_06::RawDisplayHandle::AppKit(
+                    raw_window_handle_06::AppKitDisplayHandle::new(),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Xlib(handle) => {
+                raw_window_handle_06::RawDisplayHandle::Xlib(
+                    raw_window_handle_06::XlibDisplayHandle::new(
+                        NonNull::new(handle.display),
+                        handle.screen,
+                    ),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Xcb(handle) => {
+                raw_window_handle_06::RawDisplayHandle::Xcb(
+                    raw_window_handle_06::XcbDisplayHandle::new(
+                        NonNull::new(handle.connection),
+                        handle.screen,
+                    ),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Windows(_) => {
+                raw_window_handle_06::RawDisplayHandle::Windows(
+                    raw_window_handle_06::WindowsDisplayHandle::new(),
+                )
+            }
+            _ => todo!(),
+        },
+        raw_window_handle: match raw_window_handle {
+            raw_window_handle::RawWindowHandle::AppKit(handle) => {
+                raw_window_handle_06::RawWindowHandle::AppKit(
+                    raw_window_handle_06::AppKitWindowHandle::new(
+                        NonNull::new(handle.ns_view).unwrap(),
+                    ),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Xlib(handle) => {
+                raw_window_handle_06::RawWindowHandle::Xlib(
+                    raw_window_handle_06::XlibWindowHandle::new(handle.window),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Xcb(handle) => {
+                raw_window_handle_06::RawWindowHandle::Xcb(
+                    raw_window_handle_06::XcbWindowHandle::new(
+                        NonZeroU32::new(handle.window).unwrap(),
+                    ),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Win32(handle) => {
+                // will this work? i have no idea!
+                let mut raw_handle = raw_window_handle_06::Win32WindowHandle::new(
+                    NonZeroIsize::new(handle.hwnd as isize).unwrap(),
+                );
+
+                raw_handle.hinstance = handle
+                    .hinstance
+                    .is_null()
+                    .then(|| NonZeroIsize::new(handle.hinstance as isize).unwrap());
+
+                raw_window_handle_06::RawWindowHandle::Win32(raw_handle)
+            }
+            _ => todo!(),
+        },
+    }
+}
+
+/// This is mostly identical to the gain example, minus some fluff, and with a GUI.
+pub struct MyPlugin {
+    params: Arc<MyPluginParams>,
+
+    /// Needed to normalize the peak meter's response based on the sample rate.
+    peak_meter_decay_weight: f32,
+    /// The current data for the peak meter. This is stored as an [`Arc`] so we can share it between
+    /// the GUI and the audio processing parts. If you have more state to share, then it's a good
+    /// idea to put all of that in a struct behind a single `Arc`.
+    ///
+    /// This is stored as voltage gain.
+    peak_meter: Arc<AtomicF32>,
+}
+
+#[derive(Params)]
+pub struct MyPluginParams {
+    /// The editor state, saved together with the parameter state so the custom scaling can be
+    /// restored.
+    #[persist = "editor-state"]
+    editor_state: Arc<CustomSoftbufferEditorState>,
+
+    #[id = "gain"]
+    pub gain: FloatParam,
+
+    #[id = "foobar"]
+    pub some_int: IntParam,
+}
+
+impl Default for MyPlugin {
+    fn default() -> Self {
+        Self {
+            params: Arc::new(MyPluginParams::default()),
+
+            peak_meter_decay_weight: 1.0,
+            peak_meter: Arc::new(AtomicF32::new(util::MINUS_INFINITY_DB)),
+        }
+    }
+}
+
+impl Default for MyPluginParams {
+    fn default() -> Self {
+        Self {
+            editor_state: CustomSoftbufferEditorState::from_size((200, 150)),
+
+            // See the main gain example for more details
+            gain: FloatParam::new(
+                "Gain",
+                util::db_to_gain(0.0),
+                FloatRange::Skewed {
+                    min: util::db_to_gain(-30.0),
+                    max: util::db_to_gain(30.0),
+                    factor: FloatRange::gain_skew_factor(-30.0, 30.0),
+                },
+            )
+            .with_smoother(SmoothingStyle::Logarithmic(50.0))
+            .with_unit(" dB")
+            .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
+            .with_string_to_value(formatters::s2v_f32_gain_to_db()),
+            some_int: IntParam::new("Something", 3, IntRange::Linear { min: 0, max: 3 }),
+        }
+    }
+}
+
+impl Plugin for MyPlugin {
+    const NAME: &'static str = "BYO GUI Example (Softbuffer)";
+    const VENDOR: &'static str = "Moist Plugins GmbH";
+    const URL: &'static str = "https://youtu.be/dQw4w9WgXcQ";
+    const EMAIL: &'static str = "info@example.com";
+
+    const VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+    const AUDIO_IO_LAYOUTS: &'static [AudioIOLayout] = &[
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(2),
+            main_output_channels: NonZeroU32::new(2),
+            ..AudioIOLayout::const_default()
+        },
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(1),
+            main_output_channels: NonZeroU32::new(1),
+            ..AudioIOLayout::const_default()
+        },
+    ];
+
+    const SAMPLE_ACCURATE_AUTOMATION: bool = true;
+
+    type SysExMessage = ();
+    type BackgroundTask = ();
+
+    fn params(&self) -> Arc<dyn Params> {
+        self.params.clone()
+    }
+
+    fn editor(&mut self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
+        Some(Box::new(CustomSoftbufferEditor {
+            params: Arc::clone(&self.params),
+            peak_meter: Arc::clone(&self.peak_meter),
+
+            // TODO: We can't get the size of the window when baseview does its own scaling, so if the
+            //       host does not set a scale factor on Windows or Linux we should just use a factor of
+            //       1. That may make the GUI tiny but it also prevents it from getting cut off.
+            #[cfg(target_os = "macos")]
+            scaling_factor: AtomicCell::new(None),
+            #[cfg(not(target_os = "macos"))]
+            scaling_factor: AtomicCell::new(Some(1.0)),
+        }))
+    }
+
+    fn initialize(
+        &mut self,
+        _audio_io_layout: &AudioIOLayout,
+        buffer_config: &BufferConfig,
+        _context: &mut impl InitContext<Self>,
+    ) -> bool {
+        // After `PEAK_METER_DECAY_MS` milliseconds of pure silence, the peak meter's value should
+        // have dropped by 12 dB
+        self.peak_meter_decay_weight = 0.25f64
+            .powf((buffer_config.sample_rate as f64 * PEAK_METER_DECAY_MS / 1000.0).recip())
+            as f32;
+
+        true
+    }
+
+    fn process(
+        &mut self,
+        buffer: &mut Buffer,
+        _aux: &mut AuxiliaryBuffers,
+        _context: &mut impl ProcessContext<Self>,
+    ) -> ProcessStatus {
+        for channel_samples in buffer.iter_samples() {
+            let mut amplitude = 0.0;
+            let num_samples = channel_samples.len();
+
+            let gain = self.params.gain.smoothed.next();
+            for sample in channel_samples {
+                *sample *= gain;
+                amplitude += *sample;
+            }
+
+            // To save resources, a plugin can (and probably should!) only perform expensive
+            // calculations that are only displayed on the GUI while the GUI is open
+            if self.params.editor_state.is_open() {
+                amplitude = (amplitude / num_samples as f32).abs();
+                let current_peak_meter = self.peak_meter.load(std::sync::atomic::Ordering::Relaxed);
+                let new_peak_meter = if amplitude > current_peak_meter {
+                    amplitude
+                } else {
+                    current_peak_meter * self.peak_meter_decay_weight
+                        + amplitude * (1.0 - self.peak_meter_decay_weight)
+                };
+
+                self.peak_meter
+                    .store(new_peak_meter, std::sync::atomic::Ordering::Relaxed)
+            }
+        }
+
+        ProcessStatus::Normal
+    }
+}
+
+impl ClapPlugin for MyPlugin {
+    const CLAP_ID: &'static str = "com.moist-plugins-gmbh.byo-gui-softbuffer";
+    const CLAP_DESCRIPTION: Option<&'static str> =
+        Some("A simple example plugin with a raw Softbuffer context for rendering");
+    const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
+    const CLAP_SUPPORT_URL: Option<&'static str> = None;
+    const CLAP_FEATURES: &'static [ClapFeature] = &[
+        ClapFeature::AudioEffect,
+        ClapFeature::Stereo,
+        ClapFeature::Mono,
+        ClapFeature::Utility,
+    ];
+}
+
+impl Vst3Plugin for MyPlugin {
+    const VST3_CLASS_ID: [u8; 16] = *b"ByoGuiSoftbuffer";
+    const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] =
+        &[Vst3SubCategory::Fx, Vst3SubCategory::Tools];
+}
+
+nih_export_clap!(MyPlugin);
+nih_export_vst3!(MyPlugin);

plugins/examples/byo_gui_softbuffer/src/main.rs

@@ -0,0 +1,7 @@
+use nih_plug::prelude::*;
+
+use byo_gui_softbuffer::MyPlugin;
+
+fn main() {
+    nih_export_standalone::<MyPlugin>();
+}

plugins/examples/byo_gui_wgpu/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "byo_gui_wgpu"
+version = "0.1.0"
+edition = "2021"
+authors = ["Billy Messenger <60663878+BillyDM@users.noreply.github.com>"]
+license = "ISC"
+
+description = "A simple example plugin with a raw WGPU context for rendering"
+
+[lib]
+# The `lib` artifact is needed for the standalone target
+crate-type = ["cdylib", "lib"]
+
+[dependencies]
+nih_plug = { path = "../../../", features = ["assert_process_allocs", "standalone"] }
+baseview = { git = "https://github.com/RustAudio/baseview.git", rev = "9a0b42c09d712777b2edb4c5e0cb6baf21e988f0" }
+wgpu = "23"
+raw-window-handle = "0.5"
+raw-window-handle-06 = { package = "raw-window-handle", version = "0.6" }
+pollster = "0.4.0"
+crossbeam = "0.8"
+atomic_float = "0.1"
+# To make the state persistable
+serde = { version = "1.0", features = ["derive"] }

plugins/examples/byo_gui_wgpu/src/lib.rs

@@ -0,0 +1,673 @@
+//! This plugin demonstrates how to "bring your own GUI toolkit" using a raw WGPU context.
+
+use baseview::{WindowHandle, WindowOpenOptions, WindowScalePolicy};
+use crossbeam::atomic::AtomicCell;
+use nih_plug::params::persist::PersistentField;
+use nih_plug::prelude::*;
+use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
+use serde::{Deserialize, Serialize};
+use std::{
+    borrow::Cow,
+    num::NonZeroIsize,
+    ptr::NonNull,
+    sync::{
+        atomic::{AtomicBool, Ordering},
+        Arc,
+    },
+};
+use wgpu::SurfaceTargetUnsafe;
+
+/// The time it takes for the peak meter to decay by 12 dB after switching to complete silence.
+const PEAK_METER_DECAY_MS: f64 = 150.0;
+
+pub struct CustomWgpuWindow {
+    gui_context: Arc<dyn GuiContext>,
+
+    device: wgpu::Device,
+    queue: wgpu::Queue,
+    pipeline: wgpu::RenderPipeline,
+    surface: wgpu::Surface<'static>,
+    surface_config: wgpu::SurfaceConfiguration,
+
+    #[allow(unused)]
+    params: Arc<MyPluginParams>,
+    #[allow(unused)]
+    peak_meter: Arc<AtomicF32>,
+}
+
+impl CustomWgpuWindow {
+    fn new(
+        window: &mut baseview::Window<'_>,
+        gui_context: Arc<dyn GuiContext>,
+        params: Arc<MyPluginParams>,
+        peak_meter: Arc<AtomicF32>,
+        scaling_factor: f32,
+    ) -> Self {
+        let target = baseview_window_to_surface_target(window);
+
+        pollster::block_on(Self::create(
+            target,
+            gui_context,
+            params,
+            peak_meter,
+            scaling_factor,
+        ))
+    }
+
+    async fn create(
+        target: SurfaceTargetUnsafe,
+        gui_context: Arc<dyn GuiContext>,
+        params: Arc<MyPluginParams>,
+        peak_meter: Arc<AtomicF32>,
+        scaling_factor: f32,
+    ) -> Self {
+        let (unscaled_width, unscaled_height) = params.editor_state.size();
+        let width = (unscaled_width as f64 * scaling_factor as f64).round() as u32;
+        let height = (unscaled_height as f64 * scaling_factor as f64).round() as u32;
+
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor::default());
+
+        let surface = unsafe { instance.create_surface_unsafe(target) }.unwrap();
+
+        let adapter = instance
+            .request_adapter(&wgpu::RequestAdapterOptions {
+                power_preference: wgpu::PowerPreference::LowPower,
+                force_fallback_adapter: false,
+                // Request an adapter which can render to our surface
+                compatible_surface: Some(&surface),
+            })
+            .await
+            .expect("Failed to find an appropriate adapter");
+
+        // Create the logical device and command queue
+        let (device, queue) = adapter
+            .request_device(
+                &wgpu::DeviceDescriptor {
+                    label: None,
+                    required_features: wgpu::Features::empty(),
+                    required_limits: wgpu::Limits::downlevel_webgl2_defaults()
+                        .using_resolution(adapter.limits()),
+                    memory_hints: wgpu::MemoryHints::MemoryUsage,
+                },
+                None,
+            )
+            .await
+            .expect("Failed to create device");
+
+        const SHADER: &str = "
+            const VERTS = array(
+                vec2<f32>(0.5, 1.0),
+                vec2<f32>(0.0, 0.0),
+                vec2<f32>(1.0, 0.0)
+            );
+
+            struct VertexOutput {
+                @builtin(position) clip_position: vec4<f32>,
+                @location(0) position: vec2<f32>,
+            };
+
+            @vertex
+            fn vs_main(
+                @builtin(vertex_index) in_vertex_index: u32,
+            ) -> VertexOutput {
+                var out: VertexOutput;
+                out.position = VERTS[in_vertex_index];
+                out.clip_position = vec4<f32>(out.position - 0.5, 0.0, 1.0);
+                return out;
+            }
+
+            @fragment
+            fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
+                return vec4<f32>(in.position, 0.5, 1.0);
+            }
+            ";
+
+        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: None,
+            source: wgpu::ShaderSource::Wgsl(Cow::Borrowed(SHADER)),
+        });
+
+        let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+            label: None,
+            bind_group_layouts: &[],
+            push_constant_ranges: &[],
+        });
+
+        let swapchain_capabilities = surface.get_capabilities(&adapter);
+        let swapchain_format = swapchain_capabilities.formats[0];
+
+        let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: None,
+            layout: Some(&pipeline_layout),
+            vertex: wgpu::VertexState {
+                module: &shader,
+                entry_point: Some("vs_main"),
+                buffers: &[],
+                compilation_options: Default::default(),
+            },
+            fragment: Some(wgpu::FragmentState {
+                module: &shader,
+                entry_point: Some("fs_main"),
+                compilation_options: Default::default(),
+                targets: &[Some(swapchain_format.into())],
+            }),
+            primitive: wgpu::PrimitiveState::default(),
+            depth_stencil: None,
+            multisample: wgpu::MultisampleState::default(),
+            multiview: None,
+            cache: None,
+        });
+
+        let surface_config = surface.get_default_config(&adapter, width, height).unwrap();
+        surface.configure(&device, &surface_config);
+
+        Self {
+            gui_context,
+            device,
+            queue,
+            pipeline,
+            surface,
+            surface_config,
+            params,
+            peak_meter,
+        }
+    }
+}
+
+impl baseview::WindowHandler for CustomWgpuWindow {
+    fn on_frame(&mut self, _window: &mut baseview::Window) {
+        // Do rendering here.
+
+        let frame = self
+            .surface
+            .get_current_texture()
+            .expect("Failed to acquire next swap chain texture");
+        let view = frame
+            .texture
+            .create_view(&wgpu::TextureViewDescriptor::default());
+        let mut encoder = self
+            .device
+            .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
+
+        {
+            let mut rpass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: None,
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: &view,
+                    resolve_target: None,
+                    ops: wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(wgpu::Color::BLACK),
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: None,
+                timestamp_writes: None,
+                occlusion_query_set: None,
+            });
+
+            rpass.set_pipeline(&self.pipeline);
+            rpass.draw(0..3, 0..1);
+        }
+
+        self.queue.submit(Some(encoder.finish()));
+        frame.present();
+    }
+
+    fn on_event(
+        &mut self,
+        _window: &mut baseview::Window,
+        event: baseview::Event,
+    ) -> baseview::EventStatus {
+        // Use this to set parameter values.
+        let _param_setter = ParamSetter::new(self.gui_context.as_ref());
+
+        match &event {
+            // Do event processing here.
+            baseview::Event::Window(event) => match event {
+                baseview::WindowEvent::Resized(window_info) => {
+                    self.params.editor_state.size.store((
+                        window_info.logical_size().width.round() as u32,
+                        window_info.logical_size().height.round() as u32,
+                    ));
+
+                    self.surface_config.width = window_info.physical_size().width;
+                    self.surface_config.height = window_info.physical_size().height;
+
+                    self.surface.configure(&self.device, &self.surface_config);
+                }
+                _ => {}
+            },
+            _ => {}
+        }
+
+        baseview::EventStatus::Captured
+    }
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct CustomWgpuEditorState {
+    /// The window's size in logical pixels before applying `scale_factor`.
+    #[serde(with = "nih_plug::params::persist::serialize_atomic_cell")]
+    size: AtomicCell<(u32, u32)>,
+    /// Whether the editor's window is currently open.
+    #[serde(skip)]
+    open: AtomicBool,
+}
+
+impl CustomWgpuEditorState {
+    pub fn from_size(size: (u32, u32)) -> Arc<Self> {
+        Arc::new(Self {
+            size: AtomicCell::new(size),
+            open: AtomicBool::new(false),
+        })
+    }
+
+    /// Returns a `(width, height)` pair for the current size of the GUI in logical pixels.
+    pub fn size(&self) -> (u32, u32) {
+        self.size.load()
+    }
+
+    /// Whether the GUI is currently visible.
+    // Called `is_open()` instead of `open()` to avoid the ambiguity.
+    pub fn is_open(&self) -> bool {
+        self.open.load(Ordering::Acquire)
+    }
+}
+
+impl<'a> PersistentField<'a, CustomWgpuEditorState> for Arc<CustomWgpuEditorState> {
+    fn set(&self, new_value: CustomWgpuEditorState) {
+        self.size.store(new_value.size.load());
+    }
+
+    fn map<F, R>(&self, f: F) -> R
+    where
+        F: Fn(&CustomWgpuEditorState) -> R,
+    {
+        f(self)
+    }
+}
+
+pub struct CustomWgpuEditor {
+    params: Arc<MyPluginParams>,
+    peak_meter: Arc<AtomicF32>,
+
+    /// The scaling factor reported by the host, if any. On macOS this will never be set and we
+    /// should use the system scaling factor instead.
+    scaling_factor: AtomicCell<Option<f32>>,
+}
+
+impl Editor for CustomWgpuEditor {
+    fn spawn(
+        &self,
+        parent: ParentWindowHandle,
+        context: Arc<dyn GuiContext>,
+    ) -> Box<dyn std::any::Any + Send> {
+        let (unscaled_width, unscaled_height) = self.params.editor_state.size();
+        let scaling_factor = self.scaling_factor.load();
+
+        let gui_context = Arc::clone(&context);
+
+        let params = Arc::clone(&self.params);
+        let peak_meter = Arc::clone(&self.peak_meter);
+
+        let window = baseview::Window::open_parented(
+            &ParentWindowHandleAdapter(parent),
+            WindowOpenOptions {
+                title: String::from("WGPU Window"),
+                // Baseview should be doing the DPI scaling for us
+                size: baseview::Size::new(unscaled_width as f64, unscaled_height as f64),
+                // NOTE: For some reason passing 1.0 here causes the UI to be scaled on macOS but
+                //       not the mouse events.
+                scale: scaling_factor
+                    .map(|factor| WindowScalePolicy::ScaleFactor(factor as f64))
+                    .unwrap_or(WindowScalePolicy::SystemScaleFactor),
+            },
+            move |window: &mut baseview::Window<'_>| -> CustomWgpuWindow {
+                CustomWgpuWindow::new(
+                    window,
+                    gui_context,
+                    params,
+                    peak_meter,
+                    scaling_factor.unwrap_or(1.0),
+                )
+            },
+        );
+
+        self.params.editor_state.open.store(true, Ordering::Release);
+        Box::new(CustomWgpuEditorHandle {
+            state: self.params.editor_state.clone(),
+            window,
+        })
+    }
+
+    fn size(&self) -> (u32, u32) {
+        self.params.editor_state.size()
+    }
+
+    fn set_scale_factor(&self, factor: f32) -> bool {
+        // If the editor is currently open then the host must not change the current HiDPI scale as
+        // we don't have a way to handle that. Ableton Live does this.
+        if self.params.editor_state.is_open() {
+            return false;
+        }
+
+        self.scaling_factor.store(Some(factor));
+        true
+    }
+
+    fn param_value_changed(&self, _id: &str, _normalized_value: f32) {
+        // As mentioned above, for now we'll always force a redraw to allow meter widgets to work
+        // correctly. In the future we can use an `Arc<AtomicBool>` and only force a redraw when
+        // that boolean is set.
+    }
+
+    fn param_modulation_changed(&self, _id: &str, _modulation_offset: f32) {}
+
+    fn param_values_changed(&self) {
+        // Same
+    }
+}
+
+/// The window handle used for [`EguiEditor`].
+struct CustomWgpuEditorHandle {
+    state: Arc<CustomWgpuEditorState>,
+    window: WindowHandle,
+}
+
+/// The window handle enum stored within 'WindowHandle' contains raw pointers. Is there a way around
+/// having this requirement?
+unsafe impl Send for CustomWgpuEditorHandle {}
+
+impl Drop for CustomWgpuEditorHandle {
+    fn drop(&mut self) {
+        self.state.open.store(false, Ordering::Release);
+        // XXX: This should automatically happen when the handle gets dropped, but apparently not
+        self.window.close();
+    }
+}
+
+/// This version of `baseview` uses a different version of `raw_window_handle than NIH-plug, so we
+/// need to adapt it ourselves.
+struct ParentWindowHandleAdapter(nih_plug::editor::ParentWindowHandle);
+
+unsafe impl HasRawWindowHandle for ParentWindowHandleAdapter {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        match self.0 {
+            ParentWindowHandle::X11Window(window) => {
+                let mut handle = raw_window_handle::XcbWindowHandle::empty();
+                handle.window = window;
+                RawWindowHandle::Xcb(handle)
+            }
+            ParentWindowHandle::AppKitNsView(ns_view) => {
+                let mut handle = raw_window_handle::AppKitWindowHandle::empty();
+                handle.ns_view = ns_view;
+                RawWindowHandle::AppKit(handle)
+            }
+            ParentWindowHandle::Win32Hwnd(hwnd) => {
+                let mut handle = raw_window_handle::Win32WindowHandle::empty();
+                handle.hwnd = hwnd;
+                RawWindowHandle::Win32(handle)
+            }
+        }
+    }
+}
+
+/// WGPU uses raw_window_handle v6, but baseview uses raw_window_handle v5, so manually convert it.
+fn baseview_window_to_surface_target(window: &baseview::Window<'_>) -> wgpu::SurfaceTargetUnsafe {
+    use raw_window_handle::{HasRawDisplayHandle, HasRawWindowHandle};
+
+    let raw_display_handle = window.raw_display_handle();
+    let raw_window_handle = window.raw_window_handle();
+
+    wgpu::SurfaceTargetUnsafe::RawHandle {
+        raw_display_handle: match raw_display_handle {
+            raw_window_handle::RawDisplayHandle::AppKit(_) => {
+                raw_window_handle_06::RawDisplayHandle::AppKit(
+                    raw_window_handle_06::AppKitDisplayHandle::new(),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Xlib(handle) => {
+                raw_window_handle_06::RawDisplayHandle::Xlib(
+                    raw_window_handle_06::XlibDisplayHandle::new(
+                        NonNull::new(handle.display),
+                        handle.screen,
+                    ),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Xcb(handle) => {
+                raw_window_handle_06::RawDisplayHandle::Xcb(
+                    raw_window_handle_06::XcbDisplayHandle::new(
+                        NonNull::new(handle.connection),
+                        handle.screen,
+                    ),
+                )
+            }
+            raw_window_handle::RawDisplayHandle::Windows(_) => {
+                raw_window_handle_06::RawDisplayHandle::Windows(
+                    raw_window_handle_06::WindowsDisplayHandle::new(),
+                )
+            }
+            _ => todo!(),
+        },
+        raw_window_handle: match raw_window_handle {
+            raw_window_handle::RawWindowHandle::AppKit(handle) => {
+                raw_window_handle_06::RawWindowHandle::AppKit(
+                    raw_window_handle_06::AppKitWindowHandle::new(
+                        NonNull::new(handle.ns_view).unwrap(),
+                    ),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Xlib(handle) => {
+                raw_window_handle_06::RawWindowHandle::Xlib(
+                    raw_window_handle_06::XlibWindowHandle::new(handle.window),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Xcb(handle) => {
+                raw_window_handle_06::RawWindowHandle::Xcb(
+                    raw_window_handle_06::XcbWindowHandle::new(
+                        NonZeroU32::new(handle.window).unwrap(),
+                    ),
+                )
+            }
+            raw_window_handle::RawWindowHandle::Win32(handle) => {
+                // will this work? i have no idea!
+                let mut raw_handle = raw_window_handle_06::Win32WindowHandle::new(
+                    NonZeroIsize::new(handle.hwnd as isize).unwrap(),
+                );
+
+                raw_handle.hinstance = handle
+                    .hinstance
+                    .is_null()
+                    .then(|| NonZeroIsize::new(handle.hinstance as isize).unwrap());
+
+                raw_window_handle_06::RawWindowHandle::Win32(raw_handle)
+            }
+            _ => todo!(),
+        },
+    }
+}
+
+/// This is mostly identical to the gain example, minus some fluff, and with a GUI.
+pub struct MyPlugin {
+    params: Arc<MyPluginParams>,
+
+    /// Needed to normalize the peak meter's response based on the sample rate.
+    peak_meter_decay_weight: f32,
+    /// The current data for the peak meter. This is stored as an [`Arc`] so we can share it between
+    /// the GUI and the audio processing parts. If you have more state to share, then it's a good
+    /// idea to put all of that in a struct behind a single `Arc`.
+    ///
+    /// This is stored as voltage gain.
+    peak_meter: Arc<AtomicF32>,
+}
+
+#[derive(Params)]
+pub struct MyPluginParams {
+    /// The editor state, saved together with the parameter state so the custom scaling can be
+    /// restored.
+    #[persist = "editor-state"]
+    editor_state: Arc<CustomWgpuEditorState>,
+
+    #[id = "gain"]
+    pub gain: FloatParam,
+
+    #[id = "foobar"]
+    pub some_int: IntParam,
+}
+
+impl Default for MyPlugin {
+    fn default() -> Self {
+        Self {
+            params: Arc::new(MyPluginParams::default()),
+
+            peak_meter_decay_weight: 1.0,
+            peak_meter: Arc::new(AtomicF32::new(util::MINUS_INFINITY_DB)),
+        }
+    }
+}
+
+impl Default for MyPluginParams {
+    fn default() -> Self {
+        Self {
+            editor_state: CustomWgpuEditorState::from_size((400, 300)),
+
+            // See the main gain example for more details
+            gain: FloatParam::new(
+                "Gain",
+                util::db_to_gain(0.0),
+                FloatRange::Skewed {
+                    min: util::db_to_gain(-30.0),
+                    max: util::db_to_gain(30.0),
+                    factor: FloatRange::gain_skew_factor(-30.0, 30.0),
+                },
+            )
+            .with_smoother(SmoothingStyle::Logarithmic(50.0))
+            .with_unit(" dB")
+            .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
+            .with_string_to_value(formatters::s2v_f32_gain_to_db()),
+            some_int: IntParam::new("Something", 3, IntRange::Linear { min: 0, max: 3 }),
+        }
+    }
+}
+
+impl Plugin for MyPlugin {
+    const NAME: &'static str = "BYO GUI Example (WGPU)";
+    const VENDOR: &'static str = "Moist Plugins GmbH";
+    const URL: &'static str = "https://youtu.be/dQw4w9WgXcQ";
+    const EMAIL: &'static str = "info@example.com";
+
+    const VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+    const AUDIO_IO_LAYOUTS: &'static [AudioIOLayout] = &[
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(2),
+            main_output_channels: NonZeroU32::new(2),
+            ..AudioIOLayout::const_default()
+        },
+        AudioIOLayout {
+            main_input_channels: NonZeroU32::new(1),
+            main_output_channels: NonZeroU32::new(1),
+            ..AudioIOLayout::const_default()
+        },
+    ];
+
+    const SAMPLE_ACCURATE_AUTOMATION: bool = true;
+
+    type SysExMessage = ();
+    type BackgroundTask = ();
+
+    fn params(&self) -> Arc<dyn Params> {
+        self.params.clone()
+    }
+
+    fn editor(&mut self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
+        Some(Box::new(CustomWgpuEditor {
+            params: Arc::clone(&self.params),
+            peak_meter: Arc::clone(&self.peak_meter),
+
+            // TODO: We can't get the size of the window when baseview does its own scaling, so if the
+            //       host does not set a scale factor on Windows or Linux we should just use a factor of
+            //       1. That may make the GUI tiny but it also prevents it from getting cut off.
+            #[cfg(target_os = "macos")]
+            scaling_factor: AtomicCell::new(None),
+            #[cfg(not(target_os = "macos"))]
+            scaling_factor: AtomicCell::new(Some(1.0)),
+        }))
+    }
+
+    fn initialize(
+        &mut self,
+        _audio_io_layout: &AudioIOLayout,
+        buffer_config: &BufferConfig,
+        _context: &mut impl InitContext<Self>,
+    ) -> bool {
+        // TODO: Figure out a way to disable log spam from wgpu.
+
+        // After `PEAK_METER_DECAY_MS` milliseconds of pure silence, the peak meter's value should
+        // have dropped by 12 dB
+        self.peak_meter_decay_weight = 0.25f64
+            .powf((buffer_config.sample_rate as f64 * PEAK_METER_DECAY_MS / 1000.0).recip())
+            as f32;
+
+        true
+    }
+
+    fn process(
+        &mut self,
+        buffer: &mut Buffer,
+        _aux: &mut AuxiliaryBuffers,
+        _context: &mut impl ProcessContext<Self>,
+    ) -> ProcessStatus {
+        for channel_samples in buffer.iter_samples() {
+            let mut amplitude = 0.0;
+            let num_samples = channel_samples.len();
+
+            let gain = self.params.gain.smoothed.next();
+            for sample in channel_samples {
+                *sample *= gain;
+                amplitude += *sample;
+            }
+
+            // To save resources, a plugin can (and probably should!) only perform expensive
+            // calculations that are only displayed on the GUI while the GUI is open
+            if self.params.editor_state.is_open() {
+                amplitude = (amplitude / num_samples as f32).abs();
+                let current_peak_meter = self.peak_meter.load(std::sync::atomic::Ordering::Relaxed);
+                let new_peak_meter = if amplitude > current_peak_meter {
+                    amplitude
+                } else {
+                    current_peak_meter * self.peak_meter_decay_weight
+                        + amplitude * (1.0 - self.peak_meter_decay_weight)
+                };
+
+                self.peak_meter
+                    .store(new_peak_meter, std::sync::atomic::Ordering::Relaxed)
+            }
+        }
+
+        ProcessStatus::Normal
+    }
+}
+
+impl ClapPlugin for MyPlugin {
+    const CLAP_ID: &'static str = "com.moist-plugins-gmbh.byo-gui-wgpu";
+    const CLAP_DESCRIPTION: Option<&'static str> =
+        Some("A simple example plugin with a raw WGPU context for rendering");
+    const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
+    const CLAP_SUPPORT_URL: Option<&'static str> = None;
+    const CLAP_FEATURES: &'static [ClapFeature] = &[
+        ClapFeature::AudioEffect,
+        ClapFeature::Stereo,
+        ClapFeature::Mono,
+        ClapFeature::Utility,
+    ];
+}
+
+impl Vst3Plugin for MyPlugin {
+    const VST3_CLASS_ID: [u8; 16] = *b"ByoGuiWGPUWooooo";
+    const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] =
+        &[Vst3SubCategory::Fx, Vst3SubCategory::Tools];
+}
+
+nih_export_clap!(MyPlugin);
+nih_export_vst3!(MyPlugin);

plugins/examples/byo_gui_wgpu/src/main.rs

@@ -0,0 +1,7 @@
+use nih_plug::prelude::*;
+
+use byo_gui_wgpu::MyPlugin;
+
+fn main() {
+    nih_export_standalone::<MyPlugin>();
+}