Added an example of animation using the keyboard

examples/README.md

@@ -25,6 +25,7 @@ don't break when rendered by mdbook.
 | [`canvas`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/render_target.rs) | Graphics | Uses a custom render target to apply post-processing effects. |
 | [`audio`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/audi.rs) | Audio | Plays back an audio file. |
 | [`keyboard`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/keyboard.rs) | Input | Moves a texture around based on keyboard input. |
+| [`keyboard_animation`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/keyboard_animation.rs) | Input | Moves a sprite with its animation around based on keyboard input. |
 | [`mouse`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/mouse.rs) | Input | Moves a texture around based on mouse input. |
 | [`gamepad`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/gamepad.rs) | Input | Displays the input from a connected gamepad. |
 | [`text_input`](https://github.com/17cupsofcoffee/tetra/blob/master/examples/text_input.rs) | Input | Displays text as it is typed in by the player. |

examples/keyboard_animation.rs

@@ -0,0 +1,85 @@
+use tetra::graphics::{self, Color, DrawParams, Vec2, Texture, Animation, Rectangle};
+use tetra::input::{self, Key};
+use tetra::{Context, ContextBuilder, State};
+
+struct GameState {
+    animation: Animation,
+    position: Vec2,
+}
+
+impl GameState {
+    fn new(ctx: &mut Context) -> tetra::Result<GameState> {
+        Ok(GameState {
+            animation: Animation::new(
+                Texture::new(ctx, "./examples/resources/tiles.png")?,
+                Rectangle::row(0.0, 256.0, 16.0, 16.0).take(8).collect(),
+                5,
+            ),
+            position: Vec2::new(240.0, 160.0),
+        })
+    }
+
+    pub fn player_idle(&mut self) {
+        self.animation.set_frames(Rectangle::row(0.0, 256.0, 16.0, 16.0).take(8).collect());
+    }
+
+    pub fn player_walk(&mut self) {
+        self.animation.set_frames(Rectangle::row(0.0, 272.0, 16.0, 16.0).take(8).collect());
+    }
+}
+
+impl State for GameState {
+    fn update(&mut self, ctx: &mut Context) -> tetra::Result {
+        self.animation.tick();
+
+        if input::is_key_down(ctx, Key::A) {
+            self.position.x -= 1.5;
+        }
+
+        if input::is_key_pressed(ctx, Key::A) {
+            self.player_walk();
+        }
+
+        if input::is_key_released(ctx, Key::A) {
+            self.player_idle();
+        }
+
+        if input::is_key_down(ctx, Key::D) {
+            self.position.x += 1.5;
+        }
+
+        if input::is_key_pressed(ctx, Key::D) {
+            self.player_walk();
+        }
+
+        if input::is_key_released(ctx, Key::D) {
+            self.player_idle();
+        }
+
+        Ok(())
+    }
+
+    fn draw(&mut self, ctx: &mut Context, _dt: f64) -> tetra::Result {
+        graphics::clear(ctx, Color::rgb(0.769, 0.812, 0.631));
+
+        graphics::draw(
+            ctx,
+            &self.animation,
+            DrawParams::new()
+                .position(self.position)
+                .origin(Vec2::new(8.0, 8.0))
+                .scale(Vec2::new(2.0, 2.0)),
+        );
+
+        Ok(())
+    }
+}
+
+fn main() -> tetra::Result {
+    ContextBuilder::new("Keyboard Input with animation", 480, 320)
+        .maximized(false)
+        .resizable(false)
+        .quit_on_escape(true)
+        .build()?
+        .run_with(GameState::new)
+}