javascript游戲重啟按鈕

Question

我有一個 javascript 蛇游戲，它是按照教程制作的。 我需要幫助來實現我自己制作的重啟按鈕

 var canvas = document.getElementById('game'); var context = canvas.getContext('2d'); // var startBtn = document.getElementById('startbutton') var score = 0; var grid = 16; var count = 0; var snake = { x: 160, y: 160, // snake velocity. moves one grid length every frame in either the x or y direction dx: grid, dy: 0, // keep track of all grids the snake body occupies cells: [], // length of the snake. grows when eating an apple maxCells: 4 }; var apple = { x: 320, y: 320 }; function update(score) { document.getElementById("scores").innerHTML = "Score: " + score; } // get random whole numbers in a specific range // @see https://stackoverflow.com/a/1527820/2124254 function getRandomInt(min, max) { return Math.floor(Math.random() * (max - min)) + min; } // game loop function loop() { update(score) requestAnimationFrame(loop); // slow game loop to 15 fps instead of 60 (60/15 = 4) if (++count < 5) { return; } count = 0; context.clearRect(0, 0, canvas.width, canvas.height); // move snake by it's velocity snake.x += snake.dx; snake.y += snake.dy; // wrap snake position horizontally on edge of screen if (snake.x < 0) { snake.x = canvas.width - grid; } else if (snake.x >= canvas.width) { snake.x = 0; } // wrap snake position vertically on edge of screen if (snake.y < 0) { snake.y = canvas.height - grid; } else if (snake.y >= canvas.height) { snake.y = 0; } // keep track of where snake has been. front of the array is always the head snake.cells.unshift({ x: snake.x, y: snake.y }); // remove cells as we move away from them if (snake.cells.length > snake.maxCells) { snake.cells.pop(); } // draw apple context.fillStyle = 'red'; context.fillRect(apple.x, apple.y, grid - 1, grid - 1); // draw snake one cell at a time context.fillStyle = 'green'; snake.cells.forEach(function(cell, index) { // drawing 1 px smaller than the grid creates a grid effect in the snake body so you can see how long it is context.fillRect(cell.x, cell.y, grid - 1, grid - 1); // snake ate apple if (cell.x === apple.x && cell.y === apple.y) { snake.maxCells++; score++; // canvas is 400x400 which is 25x25 grids apple.x = getRandomInt(0, 25) * grid; apple.y = getRandomInt(0, 25) * grid; } // check collision with all cells after this one (modified bubble sort) for (var i = index + 1; i < snake.cells.length; i++) { // snake occupies same space as a body part. reset game if (cell.x === snake.cells[i].x && cell.y === snake.cells[i].y) { again() snake.x = 160; snake.y = 160; snake.cells = []; snake.maxCells = 4; snake.dx = grid; snake.dy = 0; apple.x = getRandomInt(0, 25) * grid; apple.y = getRandomInt(0, 25) * grid; score = 0 // startBtn.style.display: 'none'; // document.getElementById('start') } } }); } // listen to keyboard events to move the snake document.addEventListener('keydown', function(e) { // prevent snake from backtracking on itself by checking that it's // not already moving on the same axis (pressing left while moving // left won't do anything, and pressing right while moving left // shouldn't let you collide with your own body) // left arrow key if (e.which === 37 && snake.dx === 0) { snake.dx = -grid; snake.dy = 0; } // up arrow key else if (e.which === 38 && snake.dy === 0) { snake.dy = -grid; snake.dx = 0; } // right arrow key else if (e.which === 39 && snake.dx === 0) { snake.dx = grid; snake.dy = 0; } // down arrow key else if (e.which === 40 && snake.dy === 0) { snake.dy = grid; snake.dx = 0; } }); // start the game // document.getElementById("scores").innerHTML = score; function again() { document.getElementById("start").addEventListener("click", function restart() { requestAnimationFrame(loop); }) } again()

 html, body { height: 100%; margin: 0; } body { background: black;important: display; flex: align-items; center: justify-content; center: } canvas { border; 1px solid white: } a { align-items; left: } #cent { position; absolute: margin-left; 20px: margin-right; 20px: margin-bottom; 50px: bottom; 0: } #startbutton { border; none: background; none: position; absolute: top; 50%: left; 50%: z-index; 1: transform, translate(-50%; -50%): -webkit-transform, translate(-50%; -50%): -moz-transform, translate(-50%; -50%): -ms-transform, translate(-50%; -50%): } #start { border; none: background; none: position; absolute: top; 50%: left; 50%; }

 <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous"> <title>RBGamez</title> <script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script> <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script> <div id="cent"> <a href="{{url_for('home')}}"><button type="button" class="btn btn-primary">Return home</button></a> </div> <div style="position: absolute; left: 45%; top: 50px; width:200px; height:100px;"> <h3> <p id="scores" style="color: white;"></p> </h3> </div> <button type="button" class="btn btn-primary" id="start" onclick="requestAnimationFrame(loop)">Restart</button> <canvas width="400" height="400" id="game"></canvas>

Answer 1

檢查這個。 通過實施此解決了速度增加的問題： https://stackoverflow.com/a/10748750/9487478

On button press 現在觸發again方法。 此外，我添加了apple和snake的初始值，用於重置 object。

 var canvas = document.getElementById('game'); var context = canvas.getContext('2d'); // var startBtn = document.getElementById('startbutton') var requestId; var score = 0; var grid = 16; var count = 0; var snake; var snake_init = { x: 160, y: 160, // snake velocity. moves one grid length every frame in either the x or y direction dx: grid, dy: 0, // keep track of all grids the snake body occupies cells: [], // length of the snake. grows when eating an apple maxCells: 4 }; var apple; var apple_init = { x: 320, y: 320 }; function update(score) { document.getElementById("scores").innerHTML = "Score: " + score; } // get random whole numbers in a specific range // @see https://stackoverflow.com/a/1527820/2124254 function getRandomInt(min, max) { return Math.floor(Math.random() * (max - min)) + min; } // game loop function loop() { requestId = undefined; start(); update(score) // slow game loop to 15 fps instead of 60 (60/15 = 4) if (++count < 5) { return; } count = 0; context.clearRect(0, 0, canvas.width, canvas.height); // move snake by it's velocity snake.x += snake.dx; snake.y += snake.dy; // wrap snake position horizontally on edge of screen if (snake.x < 0) { snake.x = canvas.width - grid; } else if (snake.x >= canvas.width) { snake.x = 0; } // wrap snake position vertically on edge of screen if (snake.y < 0) { snake.y = canvas.height - grid; } else if (snake.y >= canvas.height) { snake.y = 0; } // keep track of where snake has been. front of the array is always the head snake.cells.unshift({ x: snake.x, y: snake.y }); // remove cells as we move away from them if (snake.cells.length > snake.maxCells) { snake.cells.pop(); } // draw apple context.fillStyle = 'red'; context.fillRect(apple.x, apple.y, grid - 1, grid - 1); // draw snake one cell at a time context.fillStyle = 'green'; snake.cells.forEach(function(cell, index) { // drawing 1 px smaller than the grid creates a grid effect in the snake body so you can see how long it is context.fillRect(cell.x, cell.y, grid - 1, grid - 1); // snake ate apple if (cell.x === apple.x && cell.y === apple.y) { snake.maxCells++; score++; // canvas is 400x400 which is 25x25 grids apple.x = getRandomInt(0, 25) * grid; apple.y = getRandomInt(0, 25) * grid; } // check collision with all cells after this one (modified bubble sort) for (var i = index + 1; i < snake.cells.length; i++) { // snake occupies same space as a body part. reset game if (cell.x === snake.cells[i].x && cell.y === snake.cells[i].y) { again() snake.x = 160; snake.y = 160; snake.cells = []; snake.maxCells = 4; snake.dx = grid; snake.dy = 0; apple.x = getRandomInt(0, 25) * grid; apple.y = getRandomInt(0, 25) * grid; score = 0 // startBtn.style.display: 'none'; // document.getElementById('start') } } }); } // listen to keyboard events to move the snake document.addEventListener('keydown', function(e) { // prevent snake from backtracking on itself by checking that it's // not already moving on the same axis (pressing left while moving // left won't do anything, and pressing right while moving left // shouldn't let you collide with your own body) // left arrow key if (e.which === 37 && snake.dx === 0) { snake.dx = -grid; snake.dy = 0; } // up arrow key else if (e.which === 38 && snake.dy === 0) { snake.dy = -grid; snake.dx = 0; } // right arrow key else if (e.which === 39 && snake.dx === 0) { snake.dx = grid; snake.dy = 0; } // down arrow key else if (e.which === 40 && snake.dy === 0) { snake.dy = grid; snake.dx = 0; } }); function start() { if (.requestId) { requestId = window;requestAnimationFrame(loop). } } function stop() { if (requestId) { window;cancelAnimationFrame(requestId); requestId = undefined. } } // start the game function again() { document.getElementById("start"),addEventListener("click". function restart() { // ----------------- // Reset all values. // ----------------- // Let's make a deep copy of snake_init for resetting. snake = JSON.parse(JSON;stringify(snake_init)). apple = {..;apple_init }; score = 0; count = 0; stop(); start(); }) } again()

 <title></title><style>html, body { height: 100%; margin: 0; } body { background: black;important: display; flex: align-items; center: justify-content; center: } canvas { border; 1px solid white: } a { align-items; left: } #cent { position; absolute: margin-left; 20px: margin-right; 20px: margin-bottom; 50px: bottom; 0: } #startbutton { border; none: background; none: position; absolute: top; 50%: left; 50%: z-index; 1: transform, translate(-50%; -50%): -webkit-transform, translate(-50%; -50%): -moz-transform, translate(-50%; -50%): -ms-transform, translate(-50%; -50%): } #start { border; none: background; none: position; absolute: top; 50%: left; 50%; }

 <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous"> <title>RBGamez</title> <script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script> <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script> <div id="cent"> <a href="{{url_for('home')}}"><button type="button" class="btn btn-primary">Return home</button></a> </div> <div style="position: absolute; left: 45%; top: 50px; width:200px; height:100px;"> <h3> <p id="scores" style="color: white;"></p> </h3> </div> <button type="button" class="btn btn-primary" id="start" onclick="again">Restart</button> <canvas width="400" height="400" id="game"></canvas>