Created
February 6, 2019 23:04
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>2D</title> | |
| <meta charset="UTF-8"> | |
| <style> | |
| body, canvas, html { margin:0; padding:0; border:0 none; } | |
| canvas { display: block; cursor: none; } | |
| </style> | |
| </head> | |
| <body> | |
| <script> | |
| var w = window.innerWidth; | |
| var h = window.innerHeight; | |
| var canvas = document.createElement("canvas"); | |
| canvas.width = w; | |
| canvas.height = h; | |
| document.body.appendChild(canvas); | |
| var ctx = canvas.getContext("2d"); | |
| var prevTime = 0; | |
| var timeDelta = 0; | |
| function loop(time) { | |
| timeDelta = time - prevTime; | |
| prevTime = time; | |
| // Process input | |
| // Update game world | |
| gameObj.update(timeDelta); | |
| // Draw | |
| ctx.fillStyle = "#000000"; | |
| ctx.fillRect(0, 0, w, h); | |
| mouseObj.draw(ctx); | |
| gameObj.draw(ctx); | |
| // Repeat | |
| window.requestAnimationFrame(loop); | |
| } | |
| var gameObj = { | |
| x: 0, | |
| y: h / 2, | |
| xVel: 0, | |
| yVel: 0, | |
| radius: 20, | |
| color: "#ff0000", | |
| update: function (timeDelta) { | |
| var dirX = mouseObj.x - this.x; | |
| var dirY = mouseObj.y - this.y; | |
| var len = Math.sqrt(dirX * dirX + dirY * dirY); | |
| dirX = dirX / len; | |
| dirY = dirY / len; | |
| this.xVel = dirX * 0.2; | |
| this.yVel = dirY * 0.2; | |
| this.x += this.xVel * timeDelta; | |
| this.y += this.yVel * timeDelta; | |
| }, | |
| draw: function (ctx) { | |
| ctx.fillStyle = this.color; | |
| ctx.beginPath(); | |
| ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2); | |
| ctx.fill(); | |
| } | |
| }; | |
| var mouseObj = { | |
| x: 0, | |
| y: 0, | |
| draw: function (ctx) { | |
| ctx.drawImage(catImg, this.x - 64, this.y - 64, 128, 128); | |
| } | |
| } | |
| canvas.onmousemove = function (event) { | |
| mouseObj.x = event.clientX; | |
| mouseObj.y = event.clientY; | |
| } | |
| var catImg = new Image(); | |
| catImg.src = "https://upload.wikimedia.org/wikipedia/commons/3/3c/Creative-Tail-Animal-cat.svg"; | |
| catImg.onload = function () { | |
| window.requestAnimationFrame(loop); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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