first throw for game of life...

Georg Hopp
1 parent 37b4ac30
Showing 3 changed files with 126 additions and 8 deletions
tutorial/wasm-game-of-life/src/lib.rs
tutorial/wasm-game-of-life/www/index.html
tutorial/wasm-game-of-life/www/index.js
--- a/tutorial/wasm-game-of-life/src/lib.rs
View file @cac13d0
+++ b/tutorial/wasm-game-of-life/src/lib.rs
View file @cac13d0
 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
View file @cac13d0
+++ b/tutorial/wasm-game-of-life/www/index.html
View file @cac13d0
@@ -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
View file @cac13d0
+++ b/tutorial/wasm-game-of-life/www/index.js
View file @cac13d0
-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);