137 lines
4.4 KiB
JavaScript
137 lines
4.4 KiB
JavaScript
// Import the WebAssembly memory at the top of the file.
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import { memory } from "wasm-game-of-life/wasm_game_of_life_bg";
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import { Universe, Cell } from "wasm-game-of-life";
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let req_id;
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let stop = false;
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const CELL_SIZE = 9; // px
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const GRID_COLOR = "#CCCCCC";
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const DEAD_COLOR = "#FFFFFF";
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const ALIVE_COLOR = "#3399FF";
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const universe = Universe.new(128,128);
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const width = universe.width();
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const height = universe.height();
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const canvas = document.getElementById("game-of-life-canvas");
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canvas.height = (CELL_SIZE + 1) * height + 1;
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canvas.width = (CELL_SIZE + 1) * width + 1;
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const ctx = canvas.getContext('2d');
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// The JavaScript runs in a requestAnimationFrame loop.
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const renderLoop = async () => {
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await new Promise(r => setTimeout(r, 200));
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universe.tick();
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drawCells();
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if (stop == false)
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req_id = requestAnimationFrame(renderLoop);
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};
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// Return Cell position
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function getCursorPos(canvas, evt) {
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const rect = canvas.getBoundingClientRect();
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const scaleX = canvas.width / rect.width;
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const scaleY = canvas.height / rect.height;
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const canvasLeft = (evt.clientX - rect.left) * scaleX;
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const canvasTop = (evt.clientY - rect.top) * scaleY;
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const row = Math.min(Math.floor(canvasTop / (CELL_SIZE + 1)), height - 1);
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const col = Math.min(Math.floor(canvasLeft / (CELL_SIZE + 1)), width - 1);
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return { row, col };
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}
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canvas.addEventListener('mouseover',
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function(evt) {
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console.log("Stopping Animation Frame");
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stop = true;
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});
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canvas.addEventListener('mouseout',
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function(evt) {
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console.log("Starting Animation Frame");
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stop = false;
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start();
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});
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// Get Mouse position
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canvas.addEventListener('click',
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function(evt) {
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var mousePos = getCursorPos(canvas, evt);
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let cellsPtr = universe.cells();
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let cells = new Uint8Array(memory.buffer, cellsPtr, width * height);
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console.log("Click position : X = " + (mousePos.row) + ", Y = " + (mousePos.col));
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const idx = universe.get_index(mousePos.row, mousePos.col);
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if (cells[idx] === Cell.Dead)
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console.log("Cell[" + idx + "] is : " + "Dead !");
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else
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console.log("Cell[" + idx + "] is : " + "Alive !");
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// Toggle it ! TODO: Do it (like in the tutorial) from Rust !
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cells[idx] = (cells[idx] === Cell.Dead) ? Cell.Alive : Cell.Dead;
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drawCells();
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});
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const drawGrid = () => {
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ctx.beginPath();
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ctx.strokeStyle = GRID_COLOR;
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// Vertical lines.
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for (let i = 0; i <= width; i++) {
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ctx.moveTo(i * (CELL_SIZE + 1) + 1, 0);
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ctx.lineTo(i * (CELL_SIZE + 1) + 1, (CELL_SIZE + 1) * height + 1);
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}
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// Horizontal lines.
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for (let j = 0; j <= height; j++) {
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ctx.moveTo(0, j * (CELL_SIZE + 1) + 1);
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ctx.lineTo((CELL_SIZE + 1) * width + 1, j * (CELL_SIZE + 1) + 1);
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}
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ctx.stroke();
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};
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// We can directly access WebAssembly's linear memory via memory, which is defined in the raw wasm module wasm_game_of_life_bg.
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// To draw the cells, we get a pointer to the universe's cells, construct a Uint8Array overlaying the cells buffer, iterate over each cell, and draw a white or black rectangle depending on whether the cell is dead or alive, respectively.
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// By working with pointers and overlays, we avoid copying the cells across the boundary on every tick.
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const drawCells = () => {
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// Modify Plus const
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const cellsPtr = universe.cells();
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const cells = new Uint8Array(memory.buffer, cellsPtr, width * height);
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ctx.beginPath();
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for (let row = 0; row < height; row++) {
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for (let col = 0; col < width; col++) {
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const idx = universe.get_index(row, col);
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ctx.fillStyle = (cells[idx] === Cell.Dead) ? DEAD_COLOR : ALIVE_COLOR;
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ctx.fillRect(
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col * (CELL_SIZE + 1) + 1, // x
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row * (CELL_SIZE + 1) + 1, // y
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CELL_SIZE, // Width
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CELL_SIZE // Height
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);
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}
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}
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ctx.stroke();
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};
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function start() {
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drawGrid();
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drawCells();
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req_id = requestAnimationFrame(renderLoop);
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}
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start();
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