More cleanup

src/main.rs

@@ -6,15 +6,15 @@ mod doodad;
 mod inputstatus;
 mod physics;
 mod ship;
-mod spriteatlas;
+mod sprite;
 
 use crate::{
 	doodad::Doodad, inputstatus::InputStatus, physics::PhysVec, physics::Position, ship::Ship,
-	spriteatlas::SpriteAtlas,
+	sprite::SpriteAtlas,
 };
 
 trait Drawable {
-	/// Return the world position of this object
+	/// Return the world position of the center of this object.
 	fn position(&self) -> PhysVec;
 
 	/// Get the position of this drawable on the screen
@@ -80,7 +80,7 @@ impl System {
 		}
 
 		s.bodies.push(Box::new(Doodad {
-			pos: Position::new_polar(PhysVec { x: 0.0, y: 0.0 }, 0.0, 0.0),
+			pos: Position::new_cartesian(0.0, 0.0),
 			sprite: "a0.png".to_owned(),
 			scale: 1,
 			angle: 0.0,
@@ -142,7 +142,7 @@ fn main() -> Result<(), String> {
 	let mut i = InputStatus::new();
 	let mut c = Camera::new();
 
-	let mut s = Ship::new(ShipKind::Gypsum);
+	let mut s = Ship::new(ShipKind::Gypsum, Position::new_cartesian(0.0, 0.0));
 
 	//let mut last_frame_time = 0f64;
 	let mut frame_start;

src/physics/body.rs

@@ -9,9 +9,9 @@ pub struct PhysBody {
 }
 
 impl PhysBody {
-	pub fn new() -> Self {
+	pub fn new(pos: PhysVec) -> Self {
 		return PhysBody {
-			pos: PhysVec { x: 200.0, y: 200.0 },
+			pos,
 			vel: PhysVec { x: 0.0, y: 0.0 },
 			mass: 1.0,
 			angle: 0.0,

src/physics/position.rs

@@ -7,6 +7,12 @@ pub enum Position {
 	Polar(PhysPol),
 }
 
+/// A convenient wrapper around PhysVec and PhysPol
+/// that allows us to position game objects (like doodads)
+/// with whatever scheme we want.
+///
+/// This should ONLY be used for game objects, physics
+/// calculations should always use PhysVec.
 impl Position {
 	pub fn new_cartesian(x: f64, y: f64) -> Self {
 		return Self::Cartesian(PhysVec { x, y });

src/ship.rs

@@ -3,6 +3,7 @@ use sdl2::video::Window;
 
 use crate::physics::PhysBody;
 use crate::physics::PhysVec;
+use crate::physics::Position;
 use crate::Camera;
 use crate::Drawable;
 use crate::ShipKind;
@@ -14,9 +15,9 @@ pub struct Ship {
 }
 
 impl Ship {
-	pub fn new(kind: ShipKind) -> Self {
+	pub fn new(kind: ShipKind, pos: Position) -> Self {
 		Ship {
-			body: PhysBody::new(),
+			body: PhysBody::new(pos.into()),
 			kind,
 		}
 	}

src/sprite.rs

@@ -19,8 +19,8 @@ pub struct Sprite<'a> {
 impl<'a> Sprite<'a> {
 	/// Draw this sprite on the screen.
 	///
-	/// Position represents on-screen position,
-	/// NOT world position.
+	/// Position represents the center of the sprite
+	/// on-screen position, NOT in the world.
 	pub fn draw(
 		&self,
 		canvas: &mut Canvas<Window>,
@@ -29,10 +29,12 @@ impl<'a> Sprite<'a> {
 		scale: f64,
 	) -> Result<(), String> {
 		let win_size = PhysVec::from(canvas.window().size());
-		let width = self.rect.width();
-		let height = self.rect.height();
 		let scale = scale * self.scale;
 
+		// Post-scale dimensions on the screen
+		let width = self.rect.width() as f64 * scale;
+		let height = self.rect.height() as f64 * scale;
+
 		// Don't draw if we're not on the screen.
 		// An offset is included to ensure we're completely
 		// off the screen. We add the whole width intentionally.
@@ -44,31 +46,16 @@ impl<'a> Sprite<'a> {
 			return Ok(());
 		}
 
-		let mut dest = Rect::new(
-			0,
-			0,
-			(width as f64 * scale) as u32,
-			(height as f64 * scale) as u32,
-		);
-		dest.center_on(Point::new(
-			(width as f64 * scale / 2.0) as i32,
-			(height as f64 * scale / 2.0) as i32,
-		));
-
-		// set the current frame for time
-		dest.set_x(position.x.round() as i32);
-		dest.set_y(position.y.round() as i32);
+		let mut dest = Rect::new(0, 0, width as u32, height as u32);
+		dest.center_on(Point::new((position.x) as i32, (position.y) as i32));
 
 		// copy the frame to the canvas
 		canvas.copy_ex(
 			&self.texture,
 			Some(self.rect),
 			Some(dest),
-			angle, // angle
-			Point::new(
-				(width as f64 * scale / 2.0) as i32,
-				(height as f64 * scale / 2.0) as i32,
-			), // center
+			angle,                                                   // angle
+			Point::new((width / 2.0) as i32, (height / 2.0) as i32), // Rotation center
 			false,
 			false,
 		)?;