Added constants

src/main.rs

@@ -16,6 +16,16 @@ mod render;
 mod ship;
 mod system;
 
+// Z-axis range for starfield stars
+pub const STARFIELD_PARALLAX_MIN: f32 = 100.0;
+pub const STARFIELD_PARALLAX_MAX: f32 = 200.0;
+// Number of stars in one starfield tile
+pub const STARFIELD_COUNT: u64 = 100;
+// Size of a square starfield tile, in game units.
+// A tile of size PARALLAX_MAX * screen-size-in-game-units
+// will completely cover a (square) screen. This depends on zoom!
+pub const STARFIELD_SIZE: u64 = STARFIELD_PARALLAX_MAX as u64 * 500;
+
 use crate::{
 	doodad::Doodad,
 	inputstatus::InputStatus,

src/render/gpustate.rs

@@ -1,11 +1,11 @@
 use anyhow::Result;
 use bytemuck;
-use cgmath::{EuclideanSpace, Matrix2, Point2};
+use cgmath::{EuclideanSpace, Matrix2, Point2, Vector2};
 use std::{iter, rc::Rc};
 use wgpu;
 use winit::{self, dpi::PhysicalSize, window::Window};
 
-use crate::Game;
+use crate::{Game, STARFIELD_COUNT, STARFIELD_SIZE};
 
 use super::{
 	globaldata::{GlobalData, GlobalDataContent},
@@ -45,7 +45,7 @@ impl GPUState {
 	// We can draw at most this many sprites on the screen.
 	// TODO: compile-time option
 	pub const SPRITE_INSTANCE_LIMIT: u64 = 100;
-	pub const STARFIELD_INSTANCE_LIMIT: u64 = 501 * 9;
+	pub const STARFIELD_INSTANCE_LIMIT: u64 = STARFIELD_COUNT * 9;
 
 	pub async fn new(window: Window) -> Result<Self> {
 		let window_size = window.inner_size();
@@ -326,7 +326,7 @@ impl GPUState {
 				camera_zoom: game.camera.zoom,
 				window_aspect: self.window_aspect,
 				starfield_texture: 1,
-				starfield_tile_size: 80000.0,
+				starfield_tile_size: STARFIELD_SIZE as f32,
 				padding: Default::default(),
 			}]),
 		);

src/system.rs

@@ -1,6 +1,7 @@
 use crate::{
 	physics::{Pfloat, Polar},
-	Doodad, Sprite, Spriteable,
+	Doodad, Sprite, Spriteable, STARFIELD_COUNT, STARFIELD_PARALLAX_MAX, STARFIELD_PARALLAX_MIN,
+	STARFIELD_SIZE,
 };
 use cgmath::{Deg, Point2};
 use rand::{self, Rng};
@@ -21,15 +22,16 @@ pub struct System {
 impl System {
 	pub fn new() -> Self {
 		let mut rng = rand::thread_rng();
+		let sz = STARFIELD_SIZE as f32 / 2.0;
 		let mut s = System {
 			bodies: Vec::new(),
-			starfield: (0..1000)
+			starfield: (0..STARFIELD_COUNT)
 				.map(|_| StarfieldStar {
 					pos: Point2 {
-						x: rng.gen_range(-40000.0..40000.0),
-						y: rng.gen_range(-40000.0..40000.0),
+						x: rng.gen_range(-sz..=sz),
+						y: rng.gen_range(-sz..=sz),
 					},
-					parallax: rng.gen_range(100.0..150.0),
+					parallax: rng.gen_range(STARFIELD_PARALLAX_MIN..STARFIELD_PARALLAX_MAX),
 					height: rng.gen_range(1.0..2.0),
 				})
 				.collect(),