Implement random seeds under wasm

dose-response.js

@@ -118,6 +118,7 @@ fetch('target/wasm32-unknown-unknown/release/dose-response.wasm')

  .then(bytes => WebAssembly.instantiate(bytes, {
    env: {
      random: Math.random,
      draw: function(ptr, len) {
        if(len % 6 != 0) {
          throw new Error("The drawcalls vector must have a multiple of 6 elements!");

src/main.rs

@@ -376,6 +376,7 @@ pub fn initialise() -> *mut State {

extern {
    fn draw(nums: *const u8, len: usize);
    fn random() -> f32;
}

src/state.rs

@@ -1,11 +1,10 @@


use animation::{AreaOfEffect, ScreenFade};
use engine::Mouse;
use keys::Keys;
use monster;
use player::Player;
use point::Point;
use util;
use rand::{self, IsaacRng, SeedableRng};

use stats::Stats;
@@ -203,8 +202,7 @@ impl State {
    ) -> State {
        let commands = VecDeque::new();
        let verifications = VecDeque::new();
        //let seed = rand::random::<u32>();
        let seed = 1234;
        let seed = util::random_seed();
        let mut writer: Box<Write> = if let Some(replay_path) = replay_path {
            match File::create(&replay_path) {
                Ok(f) => {

src/util.rs

@@ -1,5 +1,7 @@
use std::time::Duration;

use rand;


/// The number of nanoseconds in a microsecond.
const NANOS_PER_MICRO: u32 = 1000;
@@ -26,3 +28,17 @@ pub fn num_microseconds(duration: Duration) -> Option<u64> {
    }
    None
}


#[cfg(not(feature = "web"))]
pub fn random_seed() -> u32 {
    rand::random::<u32>()
}

#[cfg(feature = "web")]
pub fn random_seed() -> u32 {
    #[allow(unsafe_code)]
    // NOTE: this comes from `Math.random` and returns a float in the <0, 1> range:
    let random_float = unsafe { ::random() };
    (random_float * ::std::u32::MAX as f32) as u32
}