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

use std::sync::Arc;

use baseview::{
    Event, EventStatus, MouseButton, MouseEvent, Size, Window, WindowEvent, WindowHandler,
    WindowInfo, WindowOpenOptions,
};
use nih_plug::prelude::*;
use pixels::{Pixels, SurfaceTexture};

use crate::{HEIGHT, WIDTH};

pub struct Emulator {}

impl Emulator {
    pub fn new() -> Self {
        Self {}
    }
}

impl Editor for Emulator {
    fn spawn(
        &self,
        parent: ParentWindowHandle,
        _context: Arc<dyn GuiContext>,
    ) -> Box<dyn std::any::Any + Send> {
        Window::open_parented(
            &parent,
            WindowOpenOptions {
                title: String::from("gb-emu"),
                size: Size::new(WIDTH as f64, HEIGHT as f64),
                scale: baseview::WindowScalePolicy::SystemScaleFactor,
            },
            EmulatorWindow::new,
        );
        Box::new(Self::new())
    }

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

    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,
    current_colour: [u8; 4],
}

impl EmulatorWindow {
    fn new(window: &mut Window) -> Self {
        let info = WindowInfo::from_logical_size(Size::new(WIDTH as f64, HEIGHT as f64), 1.);

        let mut pix = init_pixbuf(info, window);

        let current_colour: [u8; 4] = [0xFF, 0x0, 0x0, 0xFF];

        for pixel in pix.get_frame_mut().chunks_exact_mut(4) {
            pixel.copy_from_slice(&current_colour);
        }

        Self {
            pix,
            current_colour,
        }
    }

    fn update_pixbuf(&mut self) {
        self.current_colour = rotate_colour(&self.current_colour);
        self.render_pixbuf();
        println!("colour now {:#?}", self.current_colour);
    }

    fn render_pixbuf(&mut self) {
        for pixel in self.pix.get_frame_mut().chunks_exact_mut(4) {
            pixel.copy_from_slice(&self.current_colour);
        }
    }
}

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

fn rotate_colour(current: &[u8; 4]) -> [u8; 4] {
    [current[1], current[2], current[0], current[3]]
}

impl WindowHandler for EmulatorWindow {
    fn on_frame(&mut self, _window: &mut Window) {
        self.pix.render().unwrap();
    }

    fn on_event(&mut self, window: &mut Window, event: baseview::Event) -> EventStatus {
        if let Event::Window(WindowEvent::Resized(info)) = event {
            self.pix = init_pixbuf(info, window);
            self.update_pixbuf();
            return EventStatus::Captured;
        }
        if let Event::Mouse(MouseEvent::ButtonPressed {
            button: MouseButton::Left,
            ..
        }) = event
        {
            println!("click!");
            self.update_pixbuf();
            return EventStatus::Captured;
        }
        EventStatus::Ignored
    }
}