Switch from rand_core to randomize (#31)

- For #7

Cargo.lock

@@ -329,7 +329,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "getrandom"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -791,7 +791,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "pixels"
 version = "0.0.1"
 dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "gilrs 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "pixels-mocks 0.1.0",
@@ -851,12 +853,9 @@ dependencies = [
 ]
 
 [[package]]
-name = "rand_core"
+name = "randomize"
-version = "0.5.1"
+version = "3.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
-]
 
 [[package]]
 name = "range-alloc"
@@ -1047,9 +1046,11 @@ dependencies = [
 name = "simple-invaders"
 version = "0.1.0"
 dependencies = [
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "line_drawing 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pcx 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "randomize 3.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1579,7 +1580,7 @@ dependencies = [
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 "checksum fxhash 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c31b6d751ae2c7f11320402d34e41349dd1016f8d5d45e48c4312bc8625af50c"
 "checksum gcc 0.3.55 (registry+https://github.com/rust-lang/crates.io-index)" = "8f5f3913fa0bfe7ee1fd8248b6b9f42a5af4b9d65ec2dd2c3c26132b950ecfc2"
-"checksum getrandom 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "473a1265acc8ff1e808cd0a1af8cee3c2ee5200916058a2ca113c29f2d903571"
+"checksum getrandom 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "e7db7ca94ed4cd01190ceee0d8a8052f08a247aa1b469a7f68c6a3b71afcf407"
 "checksum gfx-backend-dx11 0.3.0 (git+https://github.com/gfx-rs/gfx?rev=3d5db15661127c8cad8d85522a68ec36c82f6e69)" = "<none>"
 "checksum gfx-backend-dx12 0.3.0 (git+https://github.com/gfx-rs/gfx?rev=3d5db15661127c8cad8d85522a68ec36c82f6e69)" = "<none>"
 "checksum gfx-backend-empty 0.3.0 (git+https://github.com/gfx-rs/gfx?rev=3d5db15661127c8cad8d85522a68ec36c82f6e69)" = "<none>"
@@ -1633,7 +1634,7 @@ dependencies = [
 "checksum quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9274b940887ce9addde99c4eee6b5c44cc494b182b97e73dc8ffdcb3397fd3f0"
 "checksum quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)" = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
 "checksum quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "053a8c8bcc71fcce321828dc897a98ab9760bef03a4fc36693c231e5b3216cfe"
-"checksum rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+"checksum randomize 3.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "88c38c99b51f33c9fcc655252bf02ac8048eb70f35244e4697b0de9c473e940a"
 "checksum range-alloc 0.1.0 (git+https://github.com/gfx-rs/gfx?rev=3d5db15661127c8cad8d85522a68ec36c82f6e69)" = "<none>"
 "checksum raw-window-handle 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2e815b85b31e4d397ca9dd8eb1d692e9cb458b9f6ae8ac2232c995dca8236f87"
 "checksum redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)" = "2439c63f3f6139d1b57529d16bc3b8bb855230c8efcc5d3a896c8bea7c3b1e84"

Cargo.toml

@@ -14,7 +14,9 @@ license = "MIT"
 wgpu = { git = "https://github.com/gfx-rs/wgpu-rs", rev = "012d08d64de924da93289c2b51fb06b22d7348cf" }
 
 [dev-dependencies]
+byteorder = "1.3"
 env_logger = "0.7"
+getrandom = "0.1"
 gilrs = "0.7"
 log = { version = "0.4", features = ["release_max_level_warn"] }
 pixels-mocks = { path = "pixels-mocks" }

examples/invaders/main.rs

@@ -26,7 +26,7 @@ fn main() -> Result<(), Error> {
         create_window("pixel invaders", &event_loop);
     let surface_texture = SurfaceTexture::new(width, height, surface);
     let mut pixels = Pixels::new(SCREEN_WIDTH as u32, SCREEN_HEIGHT as u32, surface_texture)?;
-    let mut invaders = World::new(debug);
+    let mut invaders = World::new(generate_seed(), debug);
     let mut time = Instant::now();
     let mut gamepad = None;
 
@@ -169,3 +169,18 @@ fn create_window(
         hidpi_factor,
     )
 }
+
+/// Generate a pseudorandom seed for the game's PRNG.
+fn generate_seed() -> (u64, u64) {
+    use byteorder::{ByteOrder, NativeEndian};
+    use getrandom::getrandom;
+
+    let mut seed = [0_u8; 16];
+
+    getrandom(&mut seed).expect("failed to getrandom");
+
+    (
+        NativeEndian::read_u64(&seed[0..8]),
+        NativeEndian::read_u64(&seed[8..16]),
+    )
+}

simple-invaders/Cargo.toml

@@ -7,4 +7,8 @@ edition = "2018"
 [dependencies]
 line_drawing = "0.8"
 pcx = "0.2"
-rand_core = { version = "0.5", features = ["std"] }
+randomize = "3.0"
+
+[dev-dependencies]
+byteorder = "1.3"
+getrandom = "0.1"

simple-invaders/src/lib.rs

@@ -4,14 +4,14 @@
 //! this in practice. That said, the game is fully functional, and it should not be too difficult
 //! to understand the code.
 
-use rand_core::{OsRng, RngCore};
 use std::time::Duration;
 
+use crate::collision::Collision;
 pub use crate::controls::{Controls, Direction};
 use crate::geo::Point;
 use crate::loader::{load_assets, Assets};
 use crate::sprites::{blit, Animation, Drawable, Frame, Sprite, SpriteRef};
-use collision::Collision;
+use randomize::PCG32;
 
 mod collision;
 mod controls;
@@ -50,7 +50,7 @@ pub struct World {
     assets: Assets,
     dt: Duration,
     gameover: bool,
-    random: OsRng,
+    prng: PCG32,
     debug: bool,
 }
 
@@ -118,7 +118,30 @@ struct Bullet {
 
 impl World {
     /// Create a new simple-invaders `World`.
-    pub fn new(debug: bool) -> World {
+    ///
+    /// # Arguments
+    ///
+    /// * `debug` - Enable debug visualizations.
+    /// * `seed` - Inputs for the pseudorandom number generator.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use byteorder::{ByteOrder, NativeEndian};
+    /// use getrandom::getrandom;
+    /// use simple_invaders::World;
+    ///
+    /// // Create a seed for the PRNG
+    /// let mut seed = [0_u8; 16];
+    /// getrandom(&mut seed).expect("failed to getrandom");
+    /// let seed = (
+    ///     NativeEndian::read_u64(&seed[0..8]),
+    ///     NativeEndian::read_u64(&seed[8..16]),
+    /// );
+    ///
+    /// let world = World::new(seed, false);
+    /// ```
+    pub fn new(seed: (u64, u64), debug: bool) -> World {
         use Frame::*;
 
         // Load assets first
@@ -150,7 +173,7 @@ impl World {
 
         let dt = Duration::default();
         let gameover = false;
-        let random = OsRng;
+        let prng = PCG32::seed(seed.0, seed.1);
 
         World {
             invaders,
@@ -163,7 +186,7 @@ impl World {
             assets,
             dt,
             gameover,
-            random,
+            prng,
             debug,
         }
     }
@@ -353,7 +376,7 @@ impl World {
         invader.sprite.step_frame(&self.assets);
 
         // They also shoot lasers at random with a 1:50 chance
-        let r = self.random.next_u32() as usize;
+        let r = self.prng.next_u32() as usize;
         let chance = r % 50;
         if self.lasers.len() < 3 && chance == 0 {
             // Pick a random column to begin searching for an invader that can fire a laser
@@ -400,9 +423,12 @@ impl World {
     }
 }
 
+/// Create a default `World` with a static PRNG seed.
 impl Default for World {
     fn default() -> Self {
-        World::new(false)
+        let seed = (6_364_136_223_846_793_005, 1);
+
+        World::new(seed, false)
     }
 }