gb-emu/gb-vst/src/ui.rs

use std::sync::{
    mpsc::{self, Receiver, Sender},
    Arc, Mutex,
};

use baseview::{
    Event, EventStatus, Size, Window, WindowEvent, WindowHandler, WindowInfo, WindowOpenOptions,
};
use gb_emu_lib::{
    connect::{Renderer, HEIGHT, WIDTH},
    util::scale_buffer,
};
use nih_plug::prelude::*;
use pixels::{Pixels, SurfaceTexture};

pub struct Emulator {
    frame_receiver: Arc<Mutex<Option<Receiver<Vec<[u8; 4]>>>>>,
}

impl Emulator {
    pub fn new(frame_receiver: Arc<Mutex<Option<Receiver<Vec<[u8; 4]>>>>>) -> Self {
        Self { frame_receiver }
    }
}

impl Editor for Emulator {
    fn spawn(
        &self,
        parent: ParentWindowHandle,
        _context: Arc<dyn GuiContext>,
    ) -> Box<dyn std::any::Any + Send> {
        let cloned = self.frame_receiver.clone();
        Window::open_parented(
            &parent,
            WindowOpenOptions {
                title: String::from("gb-emu"),
                size: Size::new(WIDTH as f64, HEIGHT as f64),
                scale: baseview::WindowScalePolicy::SystemScaleFactor,
                gl_config: None,
            },
            |w| EmulatorWindow::new(w, cloned),
        );
        Box::new(Self::new(self.frame_receiver.clone()))
    }

    fn size(&self) -> (u32, u32) {
        (WIDTH as u32, HEIGHT as u32)
    }

    fn set_scale_factor(&self, _factor: f32) -> bool {
        true
    }

    fn param_value_changed(&self, _id: &str, _normalized_value: f32) {}

    fn param_modulation_changed(&self, _id: &str, _modulation_offset: f32) {}

    fn param_values_changed(&self) {}
}

pub struct EmulatorWindow {
    pix: Pixels,
    scale: usize,
    frame_receiver: Arc<Mutex<Option<Receiver<Vec<[u8; 4]>>>>>,
}

impl EmulatorWindow {
    fn new(
        window: &mut Window,
        frame_receiver: Arc<Mutex<Option<Receiver<Vec<[u8; 4]>>>>>,
    ) -> Self {
        let info = WindowInfo::from_logical_size(Size::new(WIDTH as f64, HEIGHT as f64), 1.);

        let (pix, scale) = init_pixbuf(info, window);

        Self {
            pix,
            scale,
            frame_receiver,
        }
    }
}

fn init_pixbuf(info: WindowInfo, window: &mut Window) -> (Pixels, usize) {
    let physical_size = info.physical_size();
    let scale = (physical_size.width as usize / WIDTH).min(physical_size.height as usize / HEIGHT);
    (
        pixels::Pixels::new(
            physical_size.width,
            physical_size.height,
            SurfaceTexture::new(physical_size.width, physical_size.height, window),
        )
        .unwrap(),
        scale,
    )
}

impl WindowHandler for EmulatorWindow {
    fn on_frame(&mut self, _window: &mut Window) {
        if let Some(ref mut receiver) = *self.frame_receiver.lock().expect("failed to lock mutex") {
            match receiver.recv() {
                Ok(buf) => {
                    let scaled_buf = if self.scale != 1 {
                        scale_buffer(&buf, WIDTH, HEIGHT, self.scale)
                    } else {
                        buf
                    };
                    for (pixel, source) in
                        self.pix.get_frame_mut().chunks_exact_mut(4).zip(scaled_buf)
                    {
                        pixel.copy_from_slice(&source);
                    }
                    self.pix.render().unwrap();
                }
                Err(e) => nih_log!("recv error: {e}"),
            }
        }
    }

    fn on_event(&mut self, window: &mut Window, event: baseview::Event) -> EventStatus {
        if let Event::Window(WindowEvent::Resized(info)) = event {
            (self.pix, self.scale) = init_pixbuf(info, window);
            return EventStatus::Captured;
        }
        EventStatus::Ignored
    }
}

pub struct EmulatorRenderer {
    tx: Sender<Vec<[u8; 4]>>,
}

impl EmulatorRenderer {
    pub(super) fn new() -> (Self, Receiver<Vec<[u8; 4]>>) {
        let (tx, rx) = mpsc::channel::<Vec<[u8; 4]>>();
        (Self { tx }, rx)
    }
}

impl Renderer<[u8; 4]> for EmulatorRenderer {
    fn prepare(&mut self, _width: usize, _height: usize) {}

    #[allow(unused_must_use)]
    fn display(&mut self, buffer: &[[u8; 4]]) {
        self.tx.send(buffer.to_vec());
    }

    fn latest_joypad_state(&mut self) -> gb_emu_lib::connect::JoypadState {
        gb_emu_lib::connect::JoypadState::default()
    }
}