影片地址:www.bilibili.com/video/BV1eg411g7c...
相關原始碼:github.com/anonymousGiga/Rust-and-...
本節,我們將給康威遊戲新增互動。
我們首先在wasm-game-of-life/www/index.html中新增button在標籤上面新增如下:
<button id="play-pause"></button>
我們將wasm-game-of-life/www/index.js修改為如下:
//import { Universe } from "wasm-game-of-life";
import { Universe, Cell } from "wasm-game-of-life";
import { memory } from "wasm-game-of-life/wasm_game_of_life_bg";
const CELL_SIZE = 5; // px
const GRID_COLOR = "#CCCCCC";
const DEAD_COLOR = "#FFFFFF";
const ALIVE_COLOR = "#000000";
const universe = Universe.new();
const width = universe.width();
const height = universe.height();
const canvas = document.getElementById("game-of-life-canvas");
canvas.height = (CELL_SIZE + 1) * height + 1;
canvas.width = (CELL_SIZE + 1) * width + 1;
const ctx = canvas.getContext('2d');
let animationId = null;
function renderLoop() {
//debugger;
drawGrid();
drawCells();
universe.tick();
//window.requestAnimationFrame(renderLoop);
animationId = requestAnimationFrame(renderLoop);
}
function isPaused() {
return animationId === null;
}
const playPauseButton = document.getElementById("play-pause");
function play() {
playPauseButton.textContent = "⏸ ";
renderLoop();
}
function pause() {
playPauseButton.textContent = "▶";
cancelAnimationFrame(animationId);
andmationId = null;
}
function drawGrid() {
ctx.beginPath();
ctx.strokeStyle = GRID_COLOR;
// Vertical lines.
for (let i = 0; i <= width; i++) {
ctx.moveTo(i * (CELL_SIZE + 1) + 1, 0);
ctx.lineTo(i * (CELL_SIZE + 1) + 1, (CELL_SIZE + 1) * height + 1);
}
// Horizontal lines.
for (let j = 0; j <= height; j++) {
ctx.moveTo(0, j * (CELL_SIZE + 1) + 1);
ctx.lineTo((CELL_SIZE + 1) * width + 1, j * (CELL_SIZE + 1) + 1);
}
ctx.stroke();
}
function getIndex(row, column) {
return row * width + column;
}
function drawCells() {
const cellsPtr = universe.cells();
const cells = new Uint8Array(memory.buffer, cellsPtr, width * height);
ctx.beginPath();
for (let row = 0; row < height; row++) {
for (let col = 0; col < width; col++) {
const idx = getIndex(row, col);
ctx.fillStyle = cells[idx] === Cell.Dead
? DEAD_COLOR
: ALIVE_COLOR;
ctx.fillRect(
col * (CELL_SIZE + 1) + 1,
row * (CELL_SIZE + 1) + 1,
CELL_SIZE,
CELL_SIZE
);
}
}
ctx.stroke();
}
//window.requestAnimationFrame(renderLoop);
playPauseButton.addEventListener("click", function() {
if (isPaused()) {
play();
} else {
pause();
}
});
在wasm-game-of-life/src/lib.rs中新增如下程式碼:
impl Cell {
fn toggle(&mut self) {
*self = match *self {
Cell::Dead => Cell::Alive,
Cell::Alive => Cell::Dead,
};
}
}
。。。
#[wasm_bindgen]
impl Universe {
// ...
pub fn toggle_cell(&mut self, row: u32, column: u32) {
let idx = self.get_index(row, column);
self.cells[idx].toggle();
}
}
然後,我們在index.js中新增如下程式碼:
canvas.addEventListener("click", function() {
const boundingRect = canvas.getBoundingClientRect();
const scaleX = canvas.width / boundingRect.width;
const scaleY = canvas.height / boundingRect.height;
const canvasLeft = (event.clientX - boundingRect.left) * scaleX;
const canvasTop = (event.clientY - boundingRect.top) * scaleY;
const row = Math.min(Math.floor(canvasTop / (CELL_SIZE + 1)), height - 1);
const col = Math.min(Math.floor(canvasLeft / (CELL_SIZE + 1)), width - 1);
universe.toggle_cell(row, col);
drawGrid();
drawCells();
});
在wasm-game-of-life目錄下執行:
wasm-pack build
在www目錄下執行:
npm run start
在瀏覽器中輸入:127.0.0.1:8080
點選按鈕可以暫停和啟動,點選網格可以改變細胞狀態。
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