first throw for game of life...

6 years ago · cac13d027e
3 changed files with 126 additions and 8 deletions
--- a/tutorial/wasm-game-of-life/src/lib.rs
+++ b/tutorial/wasm-game-of-life/src/lib.rs
@ -1,5 +1,6 @@
 mod utils;
 use std::fmt::{Display, Formatter, Result};
 use wasm_bindgen::prelude::*;
 // When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
@ -9,11 +10,105 @@ use wasm_bindgen::prelude::*;
 static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
 #[wasm_bindgen]
 extern {
    fn alert(s: &str);
 #[repr(u8)]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum Cell {
    Dead  = 0,
    Alive = 1,
 }
 #[wasm_bindgen]
 pub fn greet(s :&str) {
    alert(&format!("Hello, {}!", s));
 pub struct Universe {
    width  :u32,
    height :u32,
    cells  :Vec<Cell>,
 }
 #[wasm_bindgen]
 impl Universe {
    pub fn new() -> Universe {
        let width  = 64;
        let height = 64;
        let init_cells = |i :u32| {
            if i % 2 == 0 || i % 7 == 0 { Cell::Alive } else { Cell::Dead }
        };
        let cells = (0..width * height).map(init_cells).collect();
        Universe {
            width:  width,
            height: height,
            cells:  cells,
        }
    }
    pub fn render(&self) -> String {
        self.to_string()
    }
    pub fn tick(&mut self) {
        let mut next = self.cells.clone();
        for row in 0..self.height {
            for col in 0..self.width {
                let idx            = self.get_index(row, col);
                let cell           = self.cells[idx];
                let live_neighbors = self.live_neighbor_count(row, col);
                // Game of life rules....
                let next_cell = match (cell, live_neighbors) {
                    (Cell::Alive, 2) |
                    (Cell::Alive, 3) => Cell::Alive,
                    (Cell::Alive, _) => Cell::Dead,
                    ( Cell::Dead, 3) => Cell::Alive,
                    (  otherwise, _) => otherwise,
                };
                next[idx] = next_cell;
            }
        }
        self.cells = next;
    }
    fn get_index(&self, row :u32, col :u32) -> usize {
        (row * self.width + col) as usize
    }
    fn live_neighbor_count(&self, row :u32, col :u32) -> u8 {
        let mut count = 0;
        for delta_row in [self.height - 1, 0, 1].iter().cloned() {
            for delta_col in [self.width - 1, 0, 1].iter().cloned() {
                if delta_row == 0 && delta_col == 0 {
                    continue;
                }
                let neighbor_row = (row + delta_row) % self.height;
                let neighbor_col = (col + delta_col) % self.width;
                let idx = self.get_index(neighbor_row, neighbor_col);
                count += self.cells[idx] as u8;
            }
        }
        count
    }
 }
 impl Display for Universe {
    fn fmt(&self, f :&mut Formatter) -> Result {
        for line in self.cells.as_slice().chunks(self.width as usize) {
            for &cell in line {
                let symbol = match cell {
                    Cell::Dead  => ' ',
                    Cell::Alive => '*',
                };
                write!(f, "{}", symbol)?;
            }
            write!(f, "\n")?;
        }
        Ok(())
    }
 }
--- a/tutorial/wasm-game-of-life/www/index.html
+++ b/tutorial/wasm-game-of-life/www/index.html
@ -2,10 +2,23 @@
 <html>
  <head>
    <meta charset="utf-8">
    <title>Hello wasm-pack!</title>
    <title>wasm-game-of-life!</title>
    <style>
        body {
            position:        absolute;
            top:             0;
            left:            0;
            width:           100%;
            height:          100%;
            display:         flex;
            flex-direction:  column;
            align-items:     center;
            justify-content: center;
        }
    </style>
  </head>
  <body>
    <noscript>This page contains webassembly and javascript content, please enable javascript in your browser.</noscript>
    <pre id="game-of-life-canvas"></pre>
    <script src="./bootstrap.js"></script>
  </body>
 </html>
--- a/tutorial/wasm-game-of-life/www/index.js
+++ b/tutorial/wasm-game-of-life/www/index.js
@ -1,3 +1,13 @@
 import * as wasm from "wasm-game-of-life";
 import { Universe } from "wasm-game-of-life";
 wasm.greet("It's all a game");
 const      pre = document.getElementById("game-of-life-canvas");
 const universe = Universe.new();
 const renderLoop = () => {
    pre.textContent = universe.render();
    universe.tick();
    requestAnimationFrame(renderLoop);
 };
 requestAnimationFrame(renderLoop);