我正在开发游戏，我想知道为什么“螃蟹”（实体）不能像“怪物”（也是实体）一样可杀死。我的意思是，如果我碰到地精怪兽，我会明白一点，但我只是越过螃蟹。
我尝试添加一个if..else，但随后播放器每秒获得数千个点。
我做错了什么？
// Create the canvas
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 512;
canvas.height = 480;
document.body.appendChild(canvas);
// Background image
var bgReady = false;
var bgImage = new Image();
bgImage.onload = function() {
bgReady = true;
};
bgImage.src = "images/background.png";
// Hero image
var heroReady = false;
var heroImage = new Image();
heroImage.onload = function() {
heroReady = true;
};
heroImage.src = "images/hero.png";
// Monster image
var monsterReady = false;
var monsterImage = new Image();
monsterImage.onload = function() {
monsterReady = true;
};
monsterImage.src = "images/monster.png";
// Crab image
var crabReady = false;
var crabImage = new Image();
crabImage.onload = function() {
crabReady = true;
};
crabImage.src = "images/old/hero.png";
// Game objects
var hero = {
speed: 300 // movement in pixels per second
};
var monster = {};
var crab = {};
var monstersCaught = 0;
// Handle keyboard controls
var keysDown = {};
addEventListener("keydown", function(e) {
keysDown[e.keyCode] = true;
}, false);
addEventListener("keyup", function(e) {
delete keysDown[e.keyCode];
}, false);
// Reset the game when the player catches a monster
var reset = function() {
hero.x = canvas.width / 2;
hero.y = canvas.height / 2;
// Throw the monster somewhere on the screen randomly
monster.x = 32 + (Math.random() * (canvas.width - 64));
monster.y = 32 + (Math.random() * (canvas.height - 64));
// Throw the crab somewhere on the screen randomly
crab.x = 32 + (Math.random() * (canvas.width - 64));
crab.y = 32 + (Math.random() * (canvas.height - 64));
};
// Update game objects
var update = function(modifier) {
if (38 in keysDown) { // Player holding up
hero.y -= hero.speed * modifier;
}
if (40 in keysDown) { // Player holding down
hero.y += hero.speed * modifier;
}
if (37 in keysDown) { // Player holding left
hero.x -= hero.speed * modifier;
}
if (39 in keysDown) { // Player holding right
hero.x += hero.speed * modifier;
}
// Are they touching?
if (
hero.x <= (monster.x + 32) && monster.x <= (hero.x + 32) && hero.y <= (monster.y + 32) && monster.y <= (hero.y + 32)
) {
++monstersCaught;
reset();
}
};
// Draw everything
var render = function() {
if (bgReady) {
ctx.drawImage(bgImage, 0, 0);
}
if (heroReady) {
ctx.drawImage(heroImage, hero.x, hero.y);
}
if (monsterReady) {
ctx.drawImage(monsterImage, monster.x, monster.y);
}
if (crabReady) {
ctx.drawImage(crabImage, crab.x, crab.y);
}
// Score
ctx.fillStyle = "rgb(250, 250, 250)";
ctx.font = "24px Helvetica";
ctx.textAlign = "left";
ctx.textBaseline = "top";
ctx.fillText("Mobs killed: " + monstersCaught, 32, 32);
};
// The main game loop
var main = function() {
var now = Date.now();
var delta = now - then;
update(delta / 1000);
render();
then = now;
// Request to do this again ASAP
requestAnimationFrame(main);
};
// Cross-browser support for requestAnimationFrame
var w = window;
requestAnimationFrame = w.requestAnimationFrame || w.webkitRequestAnimationFrame || w.msRequestAnimationFrame || w.mozRequestAnimationFrame;
// Let's play this game!
var then = Date.now();
reset();
main();<!DOCTYPE html>
<html>
<head>
<title>Underbound</title>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div class="game">
<script src="js/game.js"></script>
</div>
</body>
</html>最佳答案
因为您只检查英雄是否与monster冲突。
hero.x <= (monster.x + 32) && monster.x <= (hero.x + 32) && hero.y <= (monster.y + 32) && monster.y <= (hero.y + 32)
相反，您可能应该创建一个函数来检查它们是否冲突：
function isColliding(a, b) {
return a.x <= (b.x + 32) && b.x <= (a.x + 32) &&
a.y <= (b.y + 32) && b.y <= (a.y + 32);
}
if (isColliding(hero, monster)) { ...
然后使用还要检查它们是否与
crab碰撞。if (isColliding(hero, crab)) { ...
如果将所有“怪物”都放入一个数组中，然后对数组中的每个怪物进行检查，那将更加可持续（直到您拥有大量的怪物）。
至于快速获得大量积分的问题：您必须从游戏区域中移除怪物（或螃蟹），并在
update阶段停止检查碰撞，否则玩家将继续与螃蟹碰撞并获得积分。一种解决方案是给怪物一个
active（或类似属性）。默认情况下，这将为true，但是当玩家与他们碰撞时，它将为false。然后，仅绘制它们，并检查是否有碰撞，如果active为true。