switch between gui/menu modes with esc, support drag-and-drop rom changing

src/main.rs

@@ -5,11 +5,16 @@ use std::ffi::CStr;
 use std::path::PathBuf;
 use std::pin::Pin;
 
-use sdl2::render::{WindowCanvas, BlendMode};
-use sdl2::image::ImageRWops;
-use sdl2::surface::Surface;
-use sdl2::pixels::{Color, PixelFormatEnum};
-use sdl2::rect::Point;
+use sdl2::{
+    EventPump,
+    event::Event,
+    image::ImageRWops,
+    keyboard::Keycode,
+    pixels::{Color, PixelFormatEnum},
+    rect::Point,
+    render::{WindowCanvas, BlendMode},
+    surface::Surface,
+};
 
 use rand::{SeedableRng, Rng};
 use rand_xoshiro::Xoshiro128Plus;
@@ -38,6 +43,20 @@ struct Opt {
     system: Option<PathBuf>,
 }
 
+enum GuiState {
+    Menus,
+    Game
+}
+
+impl GuiState {
+    fn toggle(&mut self) {
+        match self {
+            GuiState::Menus => *self = GuiState::Game,
+            GuiState::Game => *self = GuiState::Menus,
+        }
+    }
+}
+
 struct Zretro {
     emu: Pin<Box<RetroComponentBase>>,
     canvas: WindowCanvas,
@@ -45,6 +64,8 @@ struct Zretro {
     rng: Xoshiro128Plus,
     ui_bg: Option<Surface<'static>>,
     snowflakes: Vec<Point>,
+    mode: GuiState,
+    event_pump: EventPump,
 }
 
 const FONT_PNG: &'static [u8] = include_bytes!("lifont.png");
@@ -53,7 +74,7 @@ impl Zretro {
     fn new(opt: Opt) -> Result<Self> {
         let mut emu = RetroComponentBase::new(&opt.core);
 
-        let geometry = emu.libretro_core().get_system_av_info().geometry;
+        let SystemAvInfo { geometry, .. } = emu.libretro_core().get_system_av_info();
         let sys_info = emu.libretro_core().get_system_info();
         let title = format!(
             "zretro - {}",
@@ -69,6 +90,8 @@ impl Zretro {
             .build()?;
         let canvas = window.into_canvas().build()?;
 
+        let event_pump = sdl_context.event_pump()?;
+
         let sdl2surf_comp = Sdl2SurfaceComponent::new(emu.libretro_core())?;
         emu.register_component(sdl2surf_comp)?;
 
@@ -86,7 +109,7 @@ impl Zretro {
         })?;
 
         emu.init().unwrap();
-        emu.load_game(&opt.rom).unwrap();
+        emu.load_game(&opt.rom).unwrap(); // TODO: optional via CLI positional arg, menu-browsable
 
         let rwops = sdl2::rwops::RWops::from_bytes(FONT_PNG)?;
         let font_shortlived = rwops.load_png()?;
@@ -114,6 +137,8 @@ impl Zretro {
             rng,
             ui_bg: Some(ui_bg),
             snowflakes,
+            mode: GuiState::Menus,
+            event_pump,
         })
     }
 
@@ -147,21 +172,55 @@ impl Zretro {
         let font_tx = tc.create_texture_from_surface(&self.font)?;
         let mut font_rect = self.font.rect();
         font_rect.set_height(64);
-        while let ControlFlow::Continue = self.emu.run() {
-            self.update_snow()?;
+        'outer: loop {
+            for event in self.event_pump.poll_iter() {
+                match event {
+                    Event::Quit { .. } => break 'outer,
+                    Event::KeyDown { keycode: Some(keycode), .. } => {
+                        match keycode {
+                            Keycode::Escape => {
+                                self.mode.toggle();
+                                let audio: &SimpleSdl2AudioComponent = self.emu.component_ref()?;
+                                match self.mode {
+                                    GuiState::Menus => audio.silence_buffer(),
+                                    GuiState::Game => {} //audio.resume(),
+                                }
+                            },
+                            _ => {}
+                        }
+                    }
+                    Event::KeyUp { .. } => {}
+                    Event::DropFile { filename, .. } => {
+                        self.emu.libretro_core().unload_game();
+                        self.emu.load_game(filename)?;
+                    }
+                    _ => {}
+                }
+            }
+
+            if let GuiState::Game = self.mode {
+                if let ControlFlow::Break = self.emu.run() {
+                    break;
+                }
+            } else {
+                let delay: &mut SleepFramerateLimitComponent = self.emu.component_mut()?;
+                delay.do_sleep();
+            }
+
             let surfcomp: &Sdl2SurfaceComponent = self.emu.component_ref()?;
-            let surface = surfcomp.surface();
-
-            let emu_tx = tc.create_texture_from_surface(surface)?;
-
-            let ui_bg_surf_ref = self.ui_bg.as_ref().ok_or("no bg?")?;
-            let mut ui_tx = tc.create_texture_from_surface(ui_bg_surf_ref)?;
-            ui_tx.set_blend_mode(BlendMode::Blend);
-
+            let emu_surf_ref = surfcomp.surface();
+            let emu_tx = tc.create_texture_from_surface(emu_surf_ref)?;
             self.canvas.clear();
             self.canvas.copy(&emu_tx, None, None)?;
-            self.canvas.copy(&ui_tx, None, None)?;
-            self.canvas.copy(&font_tx, font_rect, font_rect)?;
+
+            if let GuiState::Menus = self.mode {
+                self.update_snow()?;
+                let ui_bg_surf_ref = self.ui_bg.as_ref().ok_or("no bg?")?;
+                let mut ui_tx = tc.create_texture_from_surface(ui_bg_surf_ref)?;
+                ui_tx.set_blend_mode(BlendMode::Blend);
+                self.canvas.copy(&ui_tx, None, None)?;
+                self.canvas.copy(&font_tx, font_rect, font_rect)?;
+            }
             self.canvas.present();
         }
         Ok(())