Add player controls and shields (#4)

examples/invaders/main.rs

@@ -29,9 +29,11 @@ fn main() -> Result<(), Error> {
     let mut fb = Pixels::new(224, 256, surface_texture)?;
     let mut invaders = World::new();
     let mut last = Instant::now();
+    let mut controls = Controls::default();
 
     event_loop.run(move |event, _, control_flow| match event {
         event::Event::WindowEvent { event, .. } => match event {
+            // Close events
             event::WindowEvent::KeyboardInput {
                 input:
                     event::KeyboardInput {
@@ -42,7 +44,41 @@ fn main() -> Result<(), Error> {
                 ..
             }
             | event::WindowEvent::CloseRequested => *control_flow = ControlFlow::Exit,
+
+            // Keyboard controls
+            event::WindowEvent::KeyboardInput {
+                input:
+                    event::KeyboardInput {
+                        virtual_keycode: Some(virtual_code),
+                        state: event::ElementState::Pressed,
+                        ..
+                    },
+                ..
+            } => match virtual_code {
+                event::VirtualKeyCode::Left => controls.direction = Direction::Left,
+                event::VirtualKeyCode::Right => controls.direction = Direction::Right,
+                event::VirtualKeyCode::Space => controls.fire = true,
+                _ => (),
+            },
+
+            event::WindowEvent::KeyboardInput {
+                input:
+                    event::KeyboardInput {
+                        virtual_keycode: Some(virtual_code),
+                        state: event::ElementState::Released,
+                        ..
+                    },
+                ..
+            } => match virtual_code {
+                event::VirtualKeyCode::Left => controls.direction = Direction::Still,
+                event::VirtualKeyCode::Right => controls.direction = Direction::Still,
+                event::VirtualKeyCode::Space => controls.fire = false,
+                _ => (),
+            },
+
+            // Redraw the screen
             event::WindowEvent::RedrawRequested => fb.render(invaders.draw()),
+
             _ => (),
         },
         event::Event::EventsCleared => {
@@ -51,13 +87,8 @@ fn main() -> Result<(), Error> {
             let dt = now.duration_since(last);
             last = now;
 
-            // TODO: Keyboard and controller input.
-            let controls = Controls {
-                direction: Direction::Still,
-                fire: false,
-            };
-
-            invaders.update(dt, controls);
+            // Update the game logic and request redraw
+            invaders.update(dt, &controls);
             window.request_redraw();
         }
         _ => (),

simple-invaders/src/controls.rs

@@ -1,4 +1,5 @@
 /// Player control inputs.
+#[derive(Debug)]
 pub struct Controls {
     /// Move the player.
     pub direction: Direction,
@@ -7,6 +8,7 @@ pub struct Controls {
 }
 
 /// The player can only move left or right, but can also be stationary.
+#[derive(Debug)]
 pub enum Direction {
     /// Do not move the player.
     Still,
@@ -15,3 +17,18 @@ pub enum Direction {
     /// Move to the right.
     Right,
 }
+
+impl Default for Controls {
+    fn default() -> Controls {
+        Controls {
+            direction: Direction::default(),
+            fire: false,
+        }
+    }
+}
+
+impl Default for Direction {
+    fn default() -> Direction {
+        Direction::Still
+    }
+}

simple-invaders/src/lib.rs

@@ -36,6 +36,7 @@ pub struct World {
     assets: Assets,
     screen: Vec<u8>,
     timing: Duration,
+    frame_count: usize,
 }
 
 /// A tiny position vector
@@ -84,6 +85,7 @@ struct Bounds {
 struct Player {
     sprite: SpriteRef,
     pos: Point,
+    last_update: usize,
 }
 
 /// The shield entity.
@@ -124,6 +126,7 @@ impl World {
         let player = Player {
             sprite: SpriteRef::new(&assets, Player1),
             pos: Point::new(80, 216),
+            last_update: 0,
         };
         let shields = (0..4)
             .map(|i| Shield {
@@ -146,6 +149,7 @@ impl World {
             assets,
             screen,
             timing: Duration::default(),
+            frame_count: 0,
         }
     }
 
@@ -155,7 +159,7 @@ impl World {
     ///
     /// * `dt`: The time delta since last update.
     /// * `controls`: The player inputs.
-    pub fn update(&mut self, dt: Duration, _controls: Controls) {
+    pub fn update(&mut self, dt: Duration, controls: &Controls) {
         let one_frame = Duration::new(0, 16_666_667);
 
         // Advance the timer by the delta time
@@ -163,11 +167,14 @@ impl World {
 
         // Step the invaders one by one
         while self.timing >= one_frame {
+            self.frame_count += 1;
             self.timing -= one_frame;
             self.step_invaders();
         }
 
-        // TODO: Handle controls to move the player
+        // Handle player movement and animation
+        self.step_player(controls);
+
         // TODO: Handle lasers and bullets
         // Movements can be multiplied by the delta-time frame count, instead of looping
     }
@@ -186,6 +193,14 @@ impl World {
             }
         }
 
+        // Draw the shields
+        for shield in &self.shields {
+            blit(&mut self.screen, &shield.pos, &shield.sprite);
+        }
+
+        // Draw the player
+        blit(&mut self.screen, &self.player.pos, &self.player.sprite);
+
         &self.screen
     }
 
@@ -204,6 +219,34 @@ impl World {
         invader.sprite.animate(&self.assets);
     }
 
+    fn step_player(&mut self, controls: &Controls) {
+        let animate_player = match controls.direction {
+            Direction::Left => {
+                if self.player.pos.x > 0 {
+                    self.player.pos.x -= 1;
+                    true
+                } else {
+                    false
+                }
+            }
+
+            Direction::Right => {
+                if self.player.pos.x < 224 - 16 {
+                    self.player.pos.x += 1;
+                    true
+                } else {
+                    false
+                }
+            }
+            _ => false,
+        };
+
+        if animate_player && self.frame_count - self.player.last_update >= 3 {
+            self.player.last_update = self.frame_count;
+            self.player.sprite.animate(&self.assets);
+        }
+    }
+
     /// Clear the screen
     fn clear(&mut self) {
         for (i, byte) in self.screen.iter_mut().enumerate() {
@@ -281,6 +324,7 @@ fn make_invader_grid(assets: &Assets) -> Vec<Vec<Option<Invader>>> {
 
     const BLIPJOY_OFFSET: Point = Point::new(3, 4);
     const FERRIS_OFFSET: Point = Point::new(3, 5);
+    const CTHULHU_OFFSET: Point = Point::new(1, 3);
 
     (0..1)
         .map(|y| {
@@ -310,7 +354,7 @@ fn make_invader_grid(assets: &Assets) -> Vec<Vec<Option<Invader>>> {
                 .map(|x| {
                     Some(Invader {
                         sprite: SpriteRef::new(assets, Cthulhu1),
-                        pos: START + BLIPJOY_OFFSET + Point::new(x, y) * GRID,
+                        pos: START + CTHULHU_OFFSET + Point::new(x, y) * GRID,
                         score: 10,
                     })
                 })