var craft; var craftStyle; var alien; var move; var windowWidth; var windowHeight; var missilesArray; var missileSpeed; var aliensArray; var alienSpeed; var totalAliens; var aliensKilled; var explosionsArray; var scaleValues; var alienInterval; var boardInterval; var score; window.onload = function(){ craft = document.getElementById("craft"); craftStyle = window.getComputedStyle(craft); alien = document.getElementById("alien"); move = 0; windowWidth = window.innerWidth; windowHeight = window.innerHeight; document.getElementById("redline").style.width = windowWidth-10+'px'; window.addEventListener('keydown',keyDownFunction); window.addEventListener('keyup',keyUpFunction); alert("Shoot all aliens before they reach the red line to win"); alert("If you are using pc,use the left and right arrow keys to navigate and space to shoot\nIf you are using mobile use the buttons and press the ship to shoot!"); alert("Good Luck!"); missilesArray = []; missileSpeed = 15; aliensArray = []; alienSpeed = 3; totalAliens = 25; aliensKilled = 0; score = 0; explosionsArray = []; scaleValues = []; alienInterval = setInterval(createAlien,5000); boardInterval = setInterval(updateBoard,100); } function keyDownFunction(e){ var code = e.keyCode||e.which; if(code==37){ e.preventDefault(); alterMoveValue(-10); } else if(code==39){ e.preventDefault(); alterMoveValue(10); } else if(code==32) createMissile(); } function keyUpFunction(e){ var code = e.keyCode||e.which; if(code==37){ e.preventDefault(); alterMoveValue(0); } else if(code==39){ e.preventDefault(); alterMoveValue(0); } } function alterMoveValue(moveValue){ move = moveValue; } function updateBoard(){ moveCraft(); moveAliens(); moveMissiles(); checkCollision(); updateExplosion(); } var explode; function createMissile(){ var missile = document.createElement("img"); missile.src = "https://i.imgur.com/tao03lm.jpg"; missile.id = "missile"+missilesArray.length; missile.style.display = "block"; missile.style.position = "absolute"; var topOfCraft = pxValue((craftStyle.getPropertyValue('top'))); missile.style.top = (topOfCraft-20)+'px'; var leftOfCraft = craftStyle.getPropertyValue('left'); var craftWidth = craftStyle.getPropertyValue('width'); var width = craft.clientWidth; var left = pxValue(leftOfCraft); missile.style.left = (left+width/2)+'px'; var article = document.getElementsByTagName("article")[0]; article.appendChild(missile); missilesArray[missilesArray.length] = missile; } function createAlien(){ if(aliensKilled==totalAliens){ gameOver(); return 0; } var alien = document.createElement("img"); alien.src = "https://i.imgur.com/dYLlwfX.png"; alien.id = "alien"+aliensArray.length; alien.style.display = "block"; alien.style.position = "absolute"; var leftOfAlien = (Math.random()*(windowWidth-35)); alien.style.left = leftOfAlien+'px'; alien.style.top = "-10px"; alien.style.width = "35px"; alien.style.height = "77px"; var article = document.getElementsByTagName("article")[0]; article.appendChild(alien); aliensArray[aliensArray.length] = alien; } function moveCraft() { craft.style.left=(pxValue(craftStyle.getPropertyValue('left'))+move)+'px'; if(pxValue(craft.style.left)<=0) craft.style.left='0px'; else if(pxValue(craft.style.left)>=windowWidth-50) craft.style.left=windowWidth-50+'px'; } function moveAliens(){ for(var i=0;i=alienX&&missileX<=(alienX+alienWidth))&&(missileY<=alienY+alienHeight)){ missilesArray.splice(j,1); aliensArray.splice(i,1); updateScore(); aliensKilled++; createExplosion(alienX,alienY,alienWidth,alienHeight); document.getElementsByTagName("article")[0].removeChild(missile); if(alien.parentNode==document.getElementsByTagName("article")[0]) document.getElementsByTagName("article")[0].removeChild(alien); } } } for(var i=0;ipxValue(redPosition)-70) gameOver(); } } function createExplosion(xcoord,ycoord,width,height){ var explosionParticles = []; for(var i=0;i<72;i++){ var canvas = document.createElement("canvas"); var initialXCenter = width/2; var initialYCenter = height/2; var radius = 35; canvas.width = width+""; canvas.height = height+""; canvas.style.position = "absolute"; canvas.style.left = xcoord+'px'; canvas.style.top = ycoord+'px'; var ctx = canvas.getContext("2d"); ctx.fillStyle = "rgb("+Math.round((Math.random()*255))+","+Math.round((Math.random()*255))+","+Math.round((Math.random()*255))+")"; ctx.beginPath(); ctx.arc(initialXCenter,initialYCenter,radius,0,2*Math.PI); ctx.fill(); ctx.stroke(); document.getElementsByTagName("article")[0].appendChild(canvas); explosionParticles[explosionParticles.length] = canvas; } explosionsArray[explosionsArray.length] = explosionParticles; scaleValues[scaleValues.length] = 1; } function updateExplosion(){ if(explosionsArray.length==0) return; for(var i=0;i

Andromeda