我的网络编程课程中有一个小项目,我应该用 javascript 制作一个小游戏。这就是游戏:两门大炮固定在游戏空间的两端。大炮轮流互相射击,玩家将大炮倾斜到一定程度并选择一个力量来射击炮弹。如果有时间,我正在考虑将添加许多其他内容。
我找到了一个不错的网站http://www.rodedev.com/tutorials/gamephysics/来帮助我学习 2d 物理,并且我已经进行了一些测试,请参见下面的代码。然而,我确实有两个大问题:
- 非平坦的地板/地面。
- 回转!
现在脚本只检查 floorDiv 的 style.top 值,因此框将始终“降落”在这一行像素上。如果我想拥有可变高度的地形,这还不够。你们对如何实现这一点有任何想法吗?无论如何要检查特定像素的颜色吗?如果是这样,我可以检查非天空或地面彩色像素并将其作为着陆标准。
我需要旋转大炮,以便玩家可以调整他们的目标!我想我会制作两个不同的大炮对象,大炮“基地”和大炮枪管。然后我可以在玩家按键时旋转炮筒。不幸的是,轮换在网络编程中似乎很难。我在http://code.google.com/p/jquery-rotate/找到了这个 jquery 插件,但我没有让它像我想要的那样工作。尽管我已经确保炮弹在图片中居中,但也有一些平移,而不仅仅是旋转。我想这可能是因为图片没有围绕它的中心旋转?请参阅下面的轮换测试代码(如果您想尝试该代码,则必须下载轮换插件)。我想我可以为每个角度拍一张照片,但这似乎有点浪费,因为否则大炮没有实际的视觉变化。
另外,如果我想同时为多个对象设置动画,你认为我应该只更改同一个 gameloop 函数中的所有对象吗?对此有什么想法吗?
以下是物理测试的代码
CSS 文件
#moveDiv {
position:absolute;
width:100px;
height:100px;
background-color:#000;
}
#floorDiv {
position:absolute;
width:800px;
height:1px;
background-color:#2E2;
}
table {
text-align:right;
}
table input {
width:35px;
}
HTML 文件
<script type="text/javascript">
//global vars
var gravity = 0.5;
var friction = 0.5;
var moving = false;
var moveDiv;
var floorDiv;
var yPos;
var xPos;
var floorPos;
var velocity_y = 0;
var velocity_x = 0;
</script>
</head>
<body onload="initialize();">
<input type="button" value="fall" onclick="fall();"></button>
<input type="button" value="Push" onclick="push();"></button>
<input type="button" value="reset" onclick="reset();"></button>
<table>
<tr>
<td>Angle: <input type="text" value="45" id="angle" /></td>
<td>Speed: <input type="text" value="10" id="speed"/></td>
</tr>
<tr>
<td>Gravity: <input type="text" value="0.5" id="gravity" /></td>
<td>Friction: <input type="text" value="0.5" id="friction" /></td>
</table>
<div id="moveDiv"></div>
<div id="floorDiv"></div>
</body>
</html>
js文件
function initialize() {
moveDiv = document.getElementById('moveDiv');
floorDiv = document.getElementById('floorDiv');
moveDiv.style.left=400;
moveDiv.style.top=50;
floorDiv.style.left=200;
floorDiv.style.top=400;
}//end initialize
function fall()
{
moving=true;
var angle = 275;
var rad = angle / (Math.pi * 2);
var scale_x = Math.cos(rad);
var scale_y = Math.sin(rad);
var moveDivSpeed = 0;
gameLoop();
}//end fall
function push()
{
moving=true;
var angle = document.getElementById('angle').value;
var rad = angle / (Math.PI * 2);
var scale_x = Math.cos(rad);
var scale_y = Math.sin(rad);
var moveDivSpeed = document.getElementById('speed').value;
friction = document.getElementById('friction').value;
gravity = document.getElementById('gravity').value;
velocity_x = moveDivSpeed*scale_x;
console.log("original velocity_x is " + velocity_x);
velocity_y = moveDivSpeed*scale_y;
gameLoop();
}
function gameLoop () {
//console.log("gameLoop start");
var len = moveDiv.style.top.length;
var presentTop = parseInt(moveDiv.style.top.substr(0, len-2));
var lenX = moveDiv.style.left.length;
var presentLeft = parseInt(moveDiv.style.left.substr(0, lenX-2));
var len2 = floorDiv.style.top.length;
var floorTop = parseInt(floorDiv.style.top.substr(0, len2-2));
if (moving == true)
{
velocity_y -= gravity;
if ((presentTop+100) - velocity_y < floorTop)
{ //if moveDiv hasn't hit the floor yet...
moveDiv.style.top = presentTop - velocity_y;
moveDiv.style.left = presentLeft + velocity_x;
}
else if (presentTop + 100 == floorTop) //if moveDiv is ON the floor
{
velocity_x = velocity_x*(1-friction);
moveDiv.style.left = presentLeft + velocity_x;
console.log("on the floor");
console.log("friction is " + friction);
console.log(" and velocity_x is " + velocity_x);
console.log("moveDiv.style.left is " +moveDiv.style.left);
if (velocity_x <= 1)
{
console.log("stopped moving");
moving = false;
}
}
else //if moveDiv will hit the floor/go through the floor this time
{
var diff = floorTop - (presentTop + 100);
moveDiv.style.top = presentTop + diff;
moveDiv.style.left = presentLeft + velocity_x;
}
}
else if (moving == false)
{
clearTimeout(runAgain);
console.log("else if moving == false");
return false;
}
var runAgain = setTimeout("gameLoop()", 5);
//console.log("end of gameLoop");
return false;
}//end gameLoop
function reset () {
moving = false;
moveDiv.style.left=400;
moveDiv.style.top=50;
floorDiv.style.left=200;
floorDiv.style.top=400;
}//end reset
旋转测试代码(仅 html 文件和旋转插件)
<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript" src="jquery.rotate.1-1.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$("#hide").click(function() {
$("p").hide(500);
$(".box").animate({height:300, opacity:0}, 1000);
});
$("#show").click(function() {
$("p").show(500);
$(".box").animate({height:100, opacity:100}, 1000);
});
$(".box").mouseenter(function() {
$(".box").animate({height:300, opacity:0}, 500);
});
$(".box").mouseleave(function() {
$(".box").animate({height:100, opacity:10}, 1000);
});
$("#move").click(function() {
$("#grey").animate({left: -300, top: -100}, 1000)
.animate({left: -600, top: 200}, 1000);
});
$("#cannonball").click(function() {
$("#cannonball").animate({"left": "+=300", "top": "-=100"}, 500)
.animate({"left": "+=300", "top": "+=100"}, 500);
});
$("p.fading").css("opacity","0.3");
$("p.fading").hover(function() {
$(this).stop().animate({opacity: 1.0}, "slow");},
function () {
$(this).stop().animate({opacity: 0.3}, "slow");
});
$("#rotateRight").click(function() {
$("#cannonball").rotate(10);
});
}); //end jquery document.ready scripts
function initialize () {
document.getElementById('box').style.top = 250;
}
</script>
<style type="text/css">
body {
background-color: #ccc;
}
.box {
background-color: #000;
width:100px;
height:100px;
margin-left:300px;
}
.divMove {
position:relative;
top:350px;
float:right;
background-color: #ddd;
width:100px;
height:100px;
margin-right:100px;
}
#cannonball {
position: relative;
}
</style>
</head>
<body onload="initialize();">
<p>Let's make this disappear and appear.</p>
<button id="hide">Hide</button>
<button id="show">Show</button>
<button id="move">Move</button>
<button id="rotateRight">Rotate+</button>
<div id="box" class="box">
</div>
<div class="divMove" id="grey">
</div>
<img src="http://dl.dropbox.com/u/18833130/Webprogrammering/test/cannonball.png" id="cannonball" border="1" />
<p class="fading">This is a paragraph that fades. Let's see how it looks.</p>
</body>
</html>
我为长篇大论和代码量道歉,但如果你想尝试一下,你基本上可以复制粘贴,我认为这样讨论会更容易!