Move boll handling and rendering into an app state

[kaka/rust-sdl-test.git] / src / app.rs

diff --git a/src/app.rs b/src/app.rs
index 746f98d..c8f8665 100644 (file)
--- a/src/app.rs
+++ b/src/app.rs
@@ -1,16 +1,29 @@
+use rand::Rng;
+use sdl2::event::Event;
 use sdl2::EventPump;
+use sdl2::keyboard::Keycode;
 use sdl2::pixels::Color;
 use sdl2::render::BlendMode;
 use sdl2::render::Canvas;
 use sdl2::video::Window;
 
 use {SCREEN_HEIGHT, SCREEN_WIDTH};
+use boll::*;
+use common::Point2D;
 use sprites::SpriteManager;
+use NS_PER_FRAME;
+
+macro_rules! point { // because I don't know how to import it from common.rs ...
+    ( $x:expr, $y:expr ) => { Point2D { x:$x, y:$y } };
+}
+
+pub type Nanoseconds = u64;
 
 pub struct App {
     pub canvas: Canvas<Window>,
     pub event_pump: EventPump,
     pub sprites: SpriteManager,
+    pub state: Box<AppState>,
 }
 
 impl App {
@@ -34,6 +47,7 @@ impl App {
             canvas,
             event_pump,
             sprites,
+            state: Box::new(ActiveState::new()),
         }
     }
 
@@ -43,3 +57,84 @@ impl App {
         }
     }
 }
+
+pub trait AppState {
+    fn update(&mut self, dt: Nanoseconds);
+    fn render(&self, canvas: &mut Canvas<Window>);
+    fn leave(&self);
+    fn on_event(&mut self, event: Event);
+}
+
+type Bollar = Vec<Box<dyn Boll>>;
+
+pub struct ActiveState {
+    bolls: Bollar,
+    boll_size: u32,
+}
+
+impl ActiveState {
+    fn new() -> ActiveState {
+        ActiveState {
+            bolls: Bollar::new(),
+            boll_size: 1,
+        }
+    }
+
+    fn change_boll_count(&mut self, delta: i32) {
+        if delta > 0 {
+            for _i in 0..delta {
+                self.add_boll();
+            }
+        } else if delta < 0 {
+            for _i in 0..delta {
+                self.bolls.pop();
+            }
+        }
+    }
+
+    fn add_boll(&mut self) {
+        let mut rng = rand::thread_rng();
+        self.bolls.push(Box::new(SquareBoll {
+            pos: point!(rng.gen_range(0, SCREEN_WIDTH) as f64, rng.gen_range(0, SCREEN_HEIGHT) as f64),
+            vel: point!(rng.gen_range(-2.0, 2.0), rng.gen_range(-2.0, 2.0)),
+        }));
+    }
+}
+
+impl AppState for ActiveState {
+    fn update(&mut self, dt: Nanoseconds) {
+        for mut b in &mut self.bolls {
+            b.update();
+        }
+
+        match dt {
+            ns if ns < (NS_PER_FRAME - 90_0000) as u64 => { self.change_boll_count(100) }
+            ns if ns > (NS_PER_FRAME + 90_0000) as u64 => { self.change_boll_count(-100) }
+            _ => {}
+        }
+    }
+
+    fn render(&self, canvas: &mut Canvas<Window>) {
+        for mut b in &self.bolls {
+            b.draw(canvas, self.boll_size);
+        }
+    }
+
+    fn leave(&self) {
+        println!("number of bolls: {}", self.bolls.len());
+    }
+
+    fn on_event(&mut self, event: Event) {
+        match event {
+            Event::KeyDown { keycode: Some(Keycode::KpPlus), .. } => { self.boll_size = std::cmp::min(self.boll_size + 1, 32) }
+            Event::KeyDown { keycode: Some(Keycode::KpMinus), .. } => { self.boll_size = std::cmp::max(self.boll_size - 1, 1) }
+            Event::MouseMotion { x, y, .. } => {
+                self.bolls.push(Box::new(CircleBoll::new(
+                    point!(x as f64, y as f64),
+                    point!(0.0, 0.0),
+                )))
+            }
+            _ => {}
+        }
+    }
+}