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<!DOCTYPE html> |
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<html> |
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<head> |
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<title>Basic Pong HTML Game</title> |
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<meta charset="UTF-8"> |
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<style> |
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html, body { |
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height: 100%; |
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margin: 0; |
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} |
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body { |
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background: black; |
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display: flex; |
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align-items: center; |
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justify-content: center; |
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} |
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</style> |
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</head> |
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<body> |
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<canvas width="750" height="585" id="game"></canvas> |
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<script> |
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const canvas = document.getElementById('game'); |
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const context = canvas.getContext('2d'); |
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const grid = 15; |
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const paddleHeight = grid * 5; // 80 |
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const maxPaddleY = canvas.height - grid - paddleHeight; |
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var paddleSpeed = 6; |
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var ballSpeed = 5; |
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const leftPaddle = { |
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// start in the middle of the game on the left side |
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x: grid * 2, |
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y: canvas.height / 2 - paddleHeight / 2, |
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width: grid, |
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height: paddleHeight, |
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// paddle velocity |
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dy: 0 |
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}; |
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const rightPaddle = { |
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// start in the middle of the game on the right side |
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x: canvas.width - grid * 3, |
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y: canvas.height / 2 - paddleHeight / 2, |
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width: grid, |
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height: paddleHeight, |
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// paddle velocity |
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dy: 0 |
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}; |
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const ball = { |
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// start in the middle of the game |
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x: canvas.width / 2, |
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y: canvas.height / 2, |
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width: grid, |
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height: grid, |
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// keep track of when need to reset the ball position |
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resetting: false, |
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// ball velocity (start going to the top-right corner) |
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dx: ballSpeed, |
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dy: -ballSpeed |
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}; |
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// check for collision between two objects using axis-aligned bounding box (AABB) |
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// @see https://developer.mozilla.org/en-US/docs/Games/Techniques/2D_collision_detection |
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function collides(obj1, obj2) { |
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return obj1.x < obj2.x + obj2.width && |
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obj1.x + obj1.width > obj2.x && |
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obj1.y < obj2.y + obj2.height && |
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obj1.y + obj1.height > obj2.y; |
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} |
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// game loop |
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function loop() { |
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requestAnimationFrame(loop); |
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context.clearRect(0,0,canvas.width,canvas.height); |
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// move paddles by their velocity |
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leftPaddle.y += leftPaddle.dy; |
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rightPaddle.y += rightPaddle.dy; |
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// prevent paddles from going through walls |
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if (leftPaddle.y < grid) { |
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leftPaddle.y = grid; |
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} |
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else if (leftPaddle.y > maxPaddleY) { |
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leftPaddle.y = maxPaddleY; |
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} |
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if (rightPaddle.y < grid) { |
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rightPaddle.y = grid; |
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} |
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else if (rightPaddle.y > maxPaddleY) { |
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rightPaddle.y = maxPaddleY; |
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} |
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// draw paddles |
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context.fillStyle = 'white'; |
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context.fillRect(leftPaddle.x, leftPaddle.y, leftPaddle.width, leftPaddle.height); |
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context.fillRect(rightPaddle.x, rightPaddle.y, rightPaddle.width, rightPaddle.height); |
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// move ball by its velocity |
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ball.x += ball.dx; |
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ball.y += ball.dy; |
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// prevent ball from going through walls by changing its velocity |
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if (ball.y < grid) { |
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ball.y = grid; |
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ball.dy *= -1; |
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} |
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else if (ball.y + grid > canvas.height - grid) { |
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ball.y = canvas.height - grid * 2; |
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ball.dy *= -1; |
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} |
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// reset ball if it goes past paddle (but only if we haven't already done so) |
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if ( (ball.x < 0 || ball.x > canvas.width) && !ball.resetting) { |
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ball.resetting = true; |
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// give some time for the player to recover before launching the ball again |
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setTimeout(() => { |
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ball.resetting = false; |
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ball.x = canvas.width / 2; |
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ball.y = canvas.height / 2; |
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}, 400); |
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} |
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// check to see if ball collides with paddle. if they do change x velocity |
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if (collides(ball, leftPaddle)) { |
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ball.dx *= -1; |
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// move ball next to the paddle otherwise the collision will happen again |
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// in the next frame |
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ball.x = leftPaddle.x + leftPaddle.width; |
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} |
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else if (collides(ball, rightPaddle)) { |
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ball.dx *= -1; |
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// move ball next to the paddle otherwise the collision will happen again |
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// in the next frame |
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ball.x = rightPaddle.x - ball.width; |
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} |
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// draw ball |
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context.fillRect(ball.x, ball.y, ball.width, ball.height); |
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// draw walls |
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context.fillStyle = 'lightgrey'; |
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context.fillRect(0, 0, canvas.width, grid); |
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context.fillRect(0, canvas.height - grid, canvas.width, canvas.height); |
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// draw dotted line down the middle |
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for (let i = grid; i < canvas.height - grid; i += grid * 2) { |
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context.fillRect(canvas.width / 2 - grid / 2, i, grid, grid); |
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} |
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} |
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// listen to keyboard events to move the paddles |
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document.addEventListener('keydown', function(e) { |
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// up arrow key |
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if (e.which === 38) { |
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rightPaddle.dy = -paddleSpeed; |
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} |
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// down arrow key |
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else if (e.which === 40) { |
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rightPaddle.dy = paddleSpeed; |
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} |
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// w key |
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if (e.which === 87) { |
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leftPaddle.dy = -paddleSpeed; |
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} |
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// a key |
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else if (e.which === 83) { |
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leftPaddle.dy = paddleSpeed; |
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} |
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}); |
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// listen to keyboard events to stop the paddle if key is released |
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document.addEventListener('keyup', function(e) { |
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if (e.which === 38 || e.which === 40) { |
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rightPaddle.dy = 0; |
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} |
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if (e.which === 83 || e.which === 87) { |
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leftPaddle.dy = 0; |
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} |
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}); |
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// start the game |
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requestAnimationFrame(loop); |
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</script> |
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</body> |
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</html> |
evryone see this:https://gist.github.com/Pro496951/a7537d2f313fbc6ebad1f74b83f84244