带有定时动画的计时器。作为“具有定时动画的 RAF”，在本例中用于克服“计时器”方法中出现的跳帧。我再次认为这很糟糕，但游戏社区发誓这是当您无法访问显示刷新时使用的最佳方法
/** SimpleFullCanvasMouse.js begin **/
var backBuff;
var bctx;
const STRIPE_WIDTH = 250;
var textWidth;
const helpText = "Click mouse to change render update method.";
var onResize = function(){
if(backBuff === undefined){
backBuff = document.createElement("canvas") ;
bctx = backBuff.getContext("2d");
}
backBuff.width = canvas.width;
backBuff.height = canvas.height;
bctx.fillStyle = "White"
bctx.fillRect(0,0,w,h);
bctx.fillStyle = "Black";
for(var i = 0; i < w; i += STRIPE_WIDTH){
bctx.fillRect(i,0,STRIPE_WIDTH/2,h) ;
}
ctx.font = "20px arial";
ctx.textAlign = "center";
ctx.font = "20px arial";
textWidth = ctx.measureText(helpText).width;
};
var tick = 0;
var displayMethod = 0;
var methods = "Timer,RAF Best Quality,Dual Timers,RAF with timed animation,Timer with timed animation".split(",");
var dualTimersActive = false;
var hdl1, hdl2
function display(timeAdvance){ // put code in here
tick += timeAdvance;
tick %= w;
ctx.drawImage(backBuff,tick-w,0);
ctx.drawImage(backBuff,tick,0);
if(textWidth !== undefined){
ctx.fillStyle = "rgba(255,255,255,0.7)";
ctx.fillRect(w /2 - textWidth/2, 0,textWidth,40);
ctx.fillStyle = "black";
ctx.fillText(helpText,w/2, 14);
ctx.fillText("Display method : " + methods[displayMethod],w/2, 34);
}
if(mouse.buttonRaw&1){
displayMethod += 1;
displayMethod %= methods.length;
mouse.buttonRaw = 0;
lastTime = null;
tick = 0;
if(dualTimersActive) {
dualTimersActive = false;
clearInterval(hdl1);
clearInterval(hdl2);
updateMethods[displayMethod]()
}
}
}
//==================================================================================================
// The following code is support code that provides me with a standard interface to various forums.
// It provides a mouse interface, a full screen canvas, and some global often used variable
// like canvas, ctx, mouse, w, h (width and height), globalTime
// This code is not intended to be part of the answer unless specified and has been formated to reduce
// display size. It should not be used as an example of how to write a canvas interface.
// By Blindman67
const U = undefined;const RESIZE_DEBOUNCE_TIME = 100;
var w,h,cw,ch,canvas,ctx,mouse,createCanvas,resizeCanvas,setGlobals,globalTime=0,resizeCount = 0;
var L = typeof log === "function" ? log : function(d){ console.log(d); }
createCanvas = function () { var c,cs; cs = (c = document.createElement("canvas")).style; cs.position = "absolute"; cs.top = cs.left = "0px"; cs.zIndex = 1000; document.body.appendChild(c); return c;}
resizeCanvas = function () {
if (canvas === U) { canvas = createCanvas(); } canvas.width = window.innerWidth; canvas.height = window.innerHeight; ctx = canvas.getContext("2d");
if (typeof setGlobals === "function") { setGlobals(); } if (typeof onResize === "function"){ resizeCount += 1; setTimeout(debounceResize,RESIZE_DEBOUNCE_TIME);}
}
function debounceResize(){ resizeCount -= 1; if(resizeCount <= 0){ onResize();}}
setGlobals = function(){ cw = (w = canvas.width) / 2; ch = (h = canvas.height) / 2; mouse.updateBounds(); }
mouse = (function(){
function preventDefault(e) { e.preventDefault(); }
var mouse = {
x : 0, y : 0, w : 0, alt : false, shift : false, ctrl : false, buttonRaw : 0, over : false, bm : [1, 2, 4, 6, 5, 3],
active : false,bounds : null, crashRecover : null, mouseEvents : "mousemove,mousedown,mouseup,mouseout,mouseover,mousewheel,DOMMouseScroll".split(",")
};
var m = mouse;
function mouseMove(e) {
var t = e.type;
m.x = e.clientX - m.bounds.left; m.y = e.clientY - m.bounds.top;
m.alt = e.altKey; m.shift = e.shiftKey; m.ctrl = e.ctrlKey;
if (t === "mousedown") { m.buttonRaw |= m.bm[e.which-1]; }
else if (t === "mouseup") { m.buttonRaw &= m.bm[e.which + 2]; }
else if (t === "mouseout") { m.buttonRaw = 0; m.over = false; }
else if (t === "mouseover") { m.over = true; }
else if (t === "mousewheel") { m.w = e.wheelDelta; }
else if (t === "DOMMouseScroll") { m.w = -e.detail; }
if (m.callbacks) { m.callbacks.forEach(c => c(e)); }
if((m.buttonRaw & 2) && m.crashRecover !== null){ if(typeof m.crashRecover === "function"){ setTimeout(m.crashRecover,0);}}
e.preventDefault();
}
m.updateBounds = function(){
if(m.active){
m.bounds = m.element.getBoundingClientRect();
}
}
m.addCallback = function (callback) {
if (typeof callback === "function") {
if (m.callbacks === U) { m.callbacks = [callback]; }
else { m.callbacks.push(callback); }
} else { throw new TypeError("mouse.addCallback argument must be a function"); }
}
m.start = function (element, blockContextMenu) {
if (m.element !== U) { m.removeMouse(); }
m.element = element === U ? document : element;
m.blockContextMenu = blockContextMenu === U ? false : blockContextMenu;
m.mouseEvents.forEach( n => { m.element.addEventListener(n, mouseMove); } );
if (m.blockContextMenu === true) { m.element.addEventListener("contextmenu", preventDefault, false); }
m.active = true;
m.updateBounds();
}
m.remove = function () {
if (m.element !== U) {
m.mouseEvents.forEach(n => { m.element.removeEventListener(n, mouseMove); } );
if (m.contextMenuBlocked === true) { m.element.removeEventListener("contextmenu", preventDefault);}
m.element = m.callbacks = m.contextMenuBlocked = U;
m.active = false;
}
}
return mouse;
})();
resizeCanvas();
mouse.start(canvas,true);
onResize()
var lastTime = null;
window.addEventListener("resize",resizeCanvas);
function clearCTX(){
ctx.setTransform(1,0,0,1,0,0); // reset transform
ctx.globalAlpha = 1; // reset alpha
ctx.clearRect(0,0,w,h); // though not needed this is here to be fair across methods and demonstrat flicker
}
function dualUpdate(){
if(!dualTimersActive) {
dualTimersActive = true;
hdl1 = setInterval( clearCTX, 1000/60);
hdl2 = setInterval(() => display(10), 1000/60);
}
}
function timerUpdate(){
timer = performance.now();
if(!lastTime){
lastTime = timer;
}
var time = (timer-lastTime) / (1000/60);
lastTime = timer;
setTimeout(updateMethods[displayMethod],1000/60);
clearCTX();
display(10*time);
}
function updateRAF(){
clearCTX();
requestAnimationFrame(updateMethods[displayMethod]);
display(10);
}
function updateRAFTimer(timer){ // Main update loop
clearCTX();
requestAnimationFrame(updateMethods[displayMethod]);
if(!timer){
timer = 0;
}
if(!lastTime){
lastTime = timer;
}
var time = (timer-lastTime) / (1000/60);
display(10 * time);
lastTime = timer;
}
displayMethod = 1;
var updateMethods = [timerUpdate,updateRAF,dualUpdate,updateRAFTimer,timerUpdate]
updateMethodsdisplayMethod;
/** SimpleFullCanvasMouse.js end **/
