Factor out ControllerState and WorldState

src/main.rs

@@ -525,6 +525,77 @@ unsafe fn point_to_model (
 	vertex_attrib_pointer (attrs ["normal"], 3, model.get_vertex_slice (2));
 }
 
+const KEY_LEFT: usize = 0;
+const KEY_RIGHT: usize = KEY_LEFT + 1;
+const KEY_UP: usize = KEY_RIGHT + 1;
+const KEY_DOWN: usize = KEY_UP + 1;
+const KEY_COUNT: usize = KEY_DOWN + 1;
+
+struct ControllerState {
+	keys: Vec <bool>,
+}
+
+impl ControllerState {
+	pub fn from_sdl_keyboard (k: &sdl2::keyboard::KeyboardState) -> Self {
+		let f = |c| k.is_scancode_pressed (c);
+		
+		Self {
+			keys: vec! [
+				f (Scancode::Left),
+				f (Scancode::Right),
+				f (Scancode::Up),
+				f (Scancode::Down),
+			],
+		}
+	}
+	
+	pub fn is_pressed (&self, code: usize) -> bool {
+		self.keys [code]
+	}
+}
+
+struct WorldState {
+	azimuth: f32,
+	altitude: f32,
+	spin_speed: i32,
+}
+
+impl WorldState {
+	pub fn new () -> Self {
+		Self {
+			azimuth: 0.0,
+			altitude: 0.0,
+			spin_speed: 0,
+		}
+	}
+	
+	pub fn step (&mut self, controller: &ControllerState) {
+		const SPIN_RAMP_TIME: i32 = 30;
+		
+		let spin_f = 4.0 * self.spin_speed as f32 / SPIN_RAMP_TIME as f32;
+		
+		if controller.is_pressed (KEY_LEFT) {
+			self.spin_speed = std::cmp::min (self.spin_speed + 1, SPIN_RAMP_TIME);
+			self.azimuth += spin_f;
+		}
+		else if controller.is_pressed (KEY_RIGHT) {
+			self.spin_speed = std::cmp::min (self.spin_speed + 1, SPIN_RAMP_TIME);
+			self.azimuth -= spin_f;
+		}
+		else if controller.is_pressed (KEY_UP) {
+			self.spin_speed = std::cmp::min (self.spin_speed + 1, SPIN_RAMP_TIME);
+			self.altitude = f32::min (90.0, self.altitude + spin_f);
+		}
+		else if controller.is_pressed (KEY_DOWN) {
+			self.spin_speed = std::cmp::min (self.spin_speed + 1, SPIN_RAMP_TIME);
+			self.altitude = f32::max (-90.0, self.altitude - spin_f);
+		}
+		else {
+			self.spin_speed = 0;
+		}
+	}
+}
+
 fn main () {
 	let sdl_context = sdl2::init ().unwrap ();
 	let video_subsystem = sdl_context.video ().unwrap ();
@@ -630,10 +701,8 @@ fn main () {
 	let mut last_frame_time = Instant::now ();
 	let mut frame = 0;
 	let mut timestep_accum = Duration::from_millis (0);
-	let mut azimuth: f32 = 0.0;
-	let mut altitude: f32 = 0.0;
-	let mut spin_speed: i32 = 0;
-	const SPIN_RAMP_TIME: i32 = 30;
+	
+	let mut state = WorldState::new ();
 	
 	let mut event_pump = sdl_context.event_pump ().unwrap ();
 	'running: loop {
@@ -647,34 +716,14 @@ fn main () {
 		
 		timestep_accum += (frame_time - last_frame_time).mul_f32 (fps_num);
 		
-		let keyboard_state = event_pump.keyboard_state ();
+		let controller = ControllerState::from_sdl_keyboard (&event_pump.keyboard_state ());
 		
 		for _ in 0..4 {
 			if timestep_accum > Duration::from_millis (fps_den) {
 				frame += 1;
 				timestep_accum -= Duration::from_millis (fps_den);
 				
-				let spin_f = 4.0 * spin_speed as f32 / SPIN_RAMP_TIME as f32;
-				
-				if keyboard_state.is_scancode_pressed (Scancode::Left) {
-					spin_speed = std::cmp::min (spin_speed + 1, SPIN_RAMP_TIME);
-					azimuth += spin_f;
-				}
-				else if keyboard_state.is_scancode_pressed (Scancode::Right) {
-					spin_speed = std::cmp::min (spin_speed + 1, SPIN_RAMP_TIME);
-					azimuth -= spin_f;
-				}
-				else if keyboard_state.is_scancode_pressed (Scancode::Up) {
-					spin_speed = std::cmp::min (spin_speed + 1, SPIN_RAMP_TIME);
-					altitude = f32::min (90.0, altitude + spin_f);
-				}
-				else if keyboard_state.is_scancode_pressed (Scancode::Down) {
-					spin_speed = std::cmp::min (spin_speed + 1, SPIN_RAMP_TIME);
-					altitude = f32::max (-90.0, altitude - spin_f);
-				}
-				else {
-					spin_speed = 0;
-				}
+				state.step (&controller);
 			}
 			else {
 				break;
@@ -698,8 +747,8 @@ fn main () {
 		window.gl_make_current (&gl_ctx).unwrap ();
 		
 		//let longitude = (frame as f32).to_radians ();
-		let longitude = azimuth.to_radians ();
-		let latitude = (altitude - 90.0).to_radians ();
+		let longitude = state.azimuth.to_radians ();
+		let latitude = (state.altitude - 90.0).to_radians ();
 		//let latitude = (frame as f32 / 5.0).to_radians ().sin () * -40.0f32.to_radians () - 75.0f32.to_radians ();
 		
 		let proj_mat = Mat4::perspective_rh_gl (30.0f32.to_radians (), 1280.0 / 720.0, 0.5, 500.0);