所以，我正在制作一个小型的网络应用程序，以便在使用画布时变得更好，但我被卡住了。我想要一个旋转的n边多边形（线条图已经有效）。游戏循环遍历网格数组（网格上的每个点都包含Point（）对象的子类），并在每个上调用tick（）方法。一切正常，直到它碰到一个ShapePoint（）对象（中间的鼠标放在画布上）。 ShapePoint的tick（）方法在某种程度上是一个无限循环。如果你把一个console.log（“hi”）放在里面，它会给你大约2000条“hi”消息，所以它正在工作（理论上）。有趣的是，尽管它正在循环通过stoke（），但没有任何事情发生！
//################################################################
// THIS IS THE PROBLEM CLASS.
// So pretty much, when the game loop calls the tick() funciton
// of ANY ShapePoint object, everything hangs. The game is still
// looping through the ENTIRE tick() function (put console.log()
// functions in and you'll see what I mean) continually, but the
// effects it is supposed to display aren't shown.
//
//################################################################
function ShapePoint(x, y, sides) {
//position variable
this.positionOnCanvas = [x, y];
//number of sides
this.N = sides;
//current step
this.step = 0;
//the array to store all the angle data
this.thetas = new Array(this.N);
//the array to store all the vertex data
this.vertList = new Array(this.N);
//function to increase all the angels by an even amount
this.stepPoints = function(s) {
//for every side
for (i=0; i<this.N; i++) {
//multiply the current 'i' value by ((360/number of sides) + current step). This serves to create points at even intervals all the way around a circle, and have it increase by s every loop
this.thetas[i] = i*((360/this.N) + s);
//get the x value with 40*cos(angle for this point). Same for y, only with sin. Round both to 2 decimal places
this.vertList[i] = [Math.round((40*(Math.cos(this.thetas[i])))*100)/100, Math.round((40*(Math.sin(this.thetas[i])))*100)/100];
//if the current angle is between 90 and 180...
if (this.thetas[i]>=90 && this.thetas[i]<=180) {
//invert the x value
this.vertList[i][0] *= -1;
//else if the angle is between 180 and 270...
} else if (this.thetas[i]>=180 && this.thetas[i]<=270) {
//invert both the x and the y values
this.vertList[i][0] *= -1;
this.vertList[i][1] *= -1;
//else if the angle is between 270 and 360...
} else if (this.thetas[i]>=270 && this.thetas[i]<=360) {
//invert the y value
this.vertList[i][1] *= -1;
}
//nothing needed for 0-90 because both are positive
}
}
this.tick = function() { //<<<<<<<<THIS IS THE PROBLEM FUNCTION!
//setup all the points forward
this.stepPoints(this.step);
//for every side in this polyogn...
for (i=0; i<this.N; i++) {
//shorten the location of the positions
var posX = this.vertList[i][0] + this.positionOnCanvas[0];
var posY = this.vertList[i][1] + this.positionOnCanvas[1];
//begin drawing
ctx.beginPath();
//move to the x and y location of the current point
ctx.moveTo(posX, posY);
//if point is not the last in the array...
if (i < this.N-1) {
//draw a line to the next point in the array
ctx.lineTo(this.vertList[i+1][0] + this.positionOnCanvas[0], this.vertList[i+1][1] + this.positionOnCanvas[1]);
//else...
} else {
//draw a line to the first point in the array
ctx.lineTo(this.vertList[0][0] + this.positionOnCanvas[0], this.vertList[0][1] + this.positionOnCanvas[1]);
}
//draw a line
ctx.strokeStyle = "#000000";
ctx.lineWidth = 0.5;
//end
ctx.stroke();
//draw the vertex
ctx.fillStyle = "orange";
ctx.fillRect(posX-2, posY-2, 4, 4);
}
//draw the origin of the polygon
ctx.fillStyle = "lightPurple";
ctx.fillRect(this.positionOnCanvas[0]-2, this.positionOnCanvas[1]-2, 4, 4);
//if the step is greater than 360, set it to 0
this.step = this.step % 36; //(thanks Neikos!)
}
}
ShapePoint.prototype = new Point();
所以我花了几个小时调整不同的东西，我不能为我的生活看到问题是什么！如果有人能搞清楚，那就太棒了。如果您需要更多关于如何实现这一点的上下文，我已经为您创建了JSFiddle。在此先感谢，这个地方总是很有帮助！
编辑::我确实意识到我的代码有点笨拙，但是我输入了所有内容真正帮助我下次学习的内容答案 0 :(得分：5)
user2310289在上述评论中是正确的：您在i和stepPoints中使用了一个全局tick变量，因此这些方法会干扰彼此。
在某些语言中，方法中使用的变量是隐式本地的，除非另有声明，但JavaScript不是这些语言之一。在JavaScript中，您需要使用var关键字来声明您的局部变量，否则它们是隐式全局变量。