Threejs实现的2D射击小游戏
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Threejs实现的2D射击小游戏,有血槽和射击冷却设定。
核心代码如下:
let artwork, canvas, rect, _x, _y, c, w, h, w2, h2, TWOPI, genetics, player, enemies, bullets, players, prevTime, nextTime, deltaTime, startTime, totalTime, isGameover, u, aPlayer, maxEnemies, generation = 1, isStarting = true;
const init = function(){
maxEnemies = 7;
isGameover = false;
const oldCanvas = document.querySelector('#game');
if( oldCanvas )
oldCanvas.remove();
else
addEventsListener();
canvas = document.createElement('canvas');
canvas.id = "game";
canvas.width = w = 1366;
canvas.height = h = 768;
w2 = w/2;
h2 = h/2;
TWOPI = Math.PI * 2;
prevTime = nextTime = deltaTime = startTime = Date.now();
totalTime = 0;
c = canvas.getContext('2d');
c.font = "25px Arial";
c.textAlign = "center";
document.body.appendChild(canvas);
rect = canvas.getBoundingClientRect();
_x = w/rect.width;
_y = h/rect.height;
genetics = new Genetics();
genetics.createPopulation();
player = new Player();
enemies = genetics.population.slice();
bullets = Array();
players = [player, ...enemies];
if( isStarting ){
startScreen();
}else{
update();
}
}
const update = function(){
nextTime = Date.now();
deltaTime = nextTime - prevTime;
totalTime += deltaTime;
for(let i = bullets.length-1; i >= 0; i--){
bullets[i].update();
if( bullets[i].isGone )
bullets.splice(i, 1)
}
for(let i = players.length-1; i >= 0 ; i--){
if( !players[i].isDead )
players[i].update(player);
}
draw();
if( player.isDead ){
gameover()
return
}
let allDead = true;
for(let i = 0; i < enemies.length; i++ ){
if( !enemies[i].isDead ){
allDead = false;
break;
}
}
if( allDead ){
endRound()
return
}
prevTime = nextTime;
u = requestAnimationFrame( update );
}
const draw = function(){
c.clearRect(0, 0, w, h);
for(let i = 0; i < bullets.length; i++){
bullets[i].show();
}
for(let i = 0; i < players.length; i++){
if( !players[i].isDead )
players[i].show();
}
c.textAlign = "start";
c.fillStyle = "black";
c.fillText("Generation: "+generation, 10, 30 )
c.textAlign = "center";
}
const endRound = function(){
totalTime = (Date.now() - startTime) / 1000;
genetics.evolve();
enemies = genetics.population.slice();
players = [player, ...enemies];
startTime = Date.now();
generation += 1;
player.health = Math.min(10, player.health + player.health * 0.15)
update();
}
const startScreen = function(){
c.clearRect(0,0,w,h);
c.drawImage(artwork, 0, 0, artwork.width, artwork.height, 0, 0, w, h);
c.fillColor = "black";
c.fillText("Click to Start", w-w2/2, h2 )
}
const gameover = function(){
if(u)
cancelAnimationFrame(u)
generation = 1;
let i = 0;
const drawGameover = function(){
c.fillStyle = "rgba(0,0,0,"+(i += 0.01)+")";
c.fillRect(0,0,w,h);
c.fillStyle = "white";
c.fillText("You have failed the human race.", w2, h2-25);
c.fillText("You should move to mars or something.", w2, h2+25);
if( i <= 1 ){
requestAnimationFrame( drawGameover );
}else{
c.fillText("Click to try again.", w2, h2/2);
isGameover = true;
}
}
drawGameover();
}
const addEventsListener = function(){
document.body.addEventListener('mousemove', e => {
player.lookAt(e.clientX * _x, e.clientY * _y);
});
document.body.addEventListener('keydown', e => {
e.preventDefault();
switch(e.keyCode){
case 37 :
case 65 :
player.isMoving.left = true;
break;
case 38 :
case 87 :
player.isMoving.up = true;
break;
case 39 :
case 68 :
player.isMoving.right = true;
break;
case 40 :
case 83 :
player.isMoving.down = true;
break;
}
});
document.body.addEventListener('keyup', e => {
e.preventDefault();
switch(e.keyCode){
case 37 :
case 65 :
player.isMoving.left = false;
break;
case 38 :
case 87 :
player.isMoving.up = false;
break;
case 39 :
case 68 :
player.isMoving.right = false;
break;
case 40 :
case 83 :
player.isMoving.down = false;
break;
}
});
document.body.addEventListener('mouseup', e => {
e.preventDefault();
player.isShooting = false;
});
document.body.addEventListener('mousedown', e => {
e.preventDefault();
if( isGameover ){
init();
return;
}
if( isStarting ){
isStarting = false;
update();
return;
}
player.isShooting = true;
});
window.onresize = _ => {
if(u)
cancelAnimationFrame(u)
isStarting = true;
init();
}
}
aPlayer = document.createElement('audio');
aPlayer.src = "sounds/shoot.mp3";
artwork = new Image();
artwork.src = "artwork.png";
artwork.onload = _ => {
init();
if( /android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ){
const control = new GuiControls();
}
}
下载链接:【https://pan.baidu.com/s/1bjhCkznBMIng1lQFNiK75g】
下载码:【gnf3】
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