Add a Rust version

This also migrates from SDL1.2+alut, which is deprecated, to SDL2, which
is not.

.gitignore

@@ -1 +1,2 @@
 letters
+/target

Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "letters"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+sdl2 = { version = "0.36.0", features = ["ttf"] }

src/main.rs

@@ -0,0 +1,99 @@
+use std::collections::HashMap;
+
+use sdl2::{ttf::{self, Font}, pixels::Color, event::Event, keyboard::Mod, render::Canvas, video::Window, rect::{Rect, Point}, audio::{AudioSpecWAV, AudioSpecDesired, AudioQueue, AudioFormatNum}, Sdl};
+
+fn main() {
+    let sdl = sdl2::init().unwrap();
+    let mut canvas = init_video(&sdl);
+
+    let ttf = ttf::init().unwrap();
+    let font = ttf.load_font("font.ttf", 600).unwrap();
+
+    let (sounds, sound_queue) = init_audio(&sdl);
+
+    canvas.set_draw_color(Color::WHITE);
+    canvas.clear();
+    canvas.present();
+
+    for event in sdl.event_pump().unwrap().wait_iter() {
+        match event {
+            Event::Quit { timestamp: _ } => { break },
+            Event::KeyDown {
+                timestamp: _,
+                window_id: _,
+                keycode,
+                scancode: _,
+                keymod,
+                repeat: _,
+            } => {
+                if let Some(c) = keycode {
+                    if c.name().len() == 1 {
+                        let c = c.name().chars().next().unwrap().to_ascii_lowercase();
+
+                        // quit on ^C
+                        if c == 'c' && (keymod & (Mod::LCTRLMOD|Mod::RCTRLMOD)) != Mod::NOMOD {
+                            break;
+                        }
+
+                        // display and play sound for any letter or number
+                        if c.is_alphanumeric() {
+                            draw_letter(&mut canvas, &font, c);
+                            sound_queue.clear();
+                            sound_queue.queue_audio(sounds.get(&c.to_ascii_lowercase()).expect(&c.to_string()).buffer()).unwrap();
+                        }
+                    }
+                }
+            }
+            _ => (),
+        };
+    }
+
+    println!("quit");
+}
+
+fn draw_letter(canvas: &mut Canvas<Window>, font: &Font, c: char) {
+    canvas.set_draw_color(Color::WHITE);
+    canvas.clear();
+
+    let ci = c as u8 % 7;
+    let text_color = Color::RGB(240*(ci&1), 240*((ci>>1)&1), 255*((ci>>2)&1));
+    let buf = if c.is_alphabetic() { c.to_ascii_uppercase().to_string() + &c.to_string() } else { c.to_string() };
+    let message = font.render(&buf).shaded(text_color, Color::WHITE).unwrap();
+    let renderer = canvas.texture_creator();
+    let texture = message.as_texture(&renderer).unwrap();
+    let dim = canvas.output_size().unwrap();
+    let dst = Rect::from_center(Point::new(dim.0 as i32/2, dim.1 as i32/2), message.width(), message.height());
+    canvas.copy(&texture, None, dst).unwrap();
+
+    canvas.present();
+}
+
+fn init_video(sdl: &Sdl) -> Canvas<Window> {
+    let video = sdl.video().unwrap();
+    let dm = video.desktop_display_mode(0).unwrap();
+    let window = sdl.video().unwrap().window("Letters", dm.w as u32, dm.h as u32).fullscreen().build().unwrap();
+    window.into_canvas().build().unwrap()
+}
+
+fn init_audio<Channel>(sdl: &Sdl) -> (HashMap<char, AudioSpecWAV>, AudioQueue<Channel>)
+where
+    Channel: AudioFormatNum
+{
+    let mut sounds: HashMap<char, AudioSpecWAV> = HashMap::default();
+    for c in ('a'..='z').chain('0'..='9') {
+        let filename = format!("sounds/{c}.wav");
+        sounds.insert(c, AudioSpecWAV::load_wav(filename).unwrap());
+    }
+    let first_sound = sounds.values().next().unwrap();
+
+    let desired = AudioSpecDesired{
+        freq: Some(first_sound.freq),
+        channels: Some(first_sound.channels),
+        samples: Some(first_sound.format as u16)
+    };
+    let audio = sdl.audio().unwrap();
+    let sound_queue = audio.open_queue(None, &desired).unwrap();
+    sound_queue.resume();
+
+    (sounds, sound_queue)
+}