ActionScript 3 三角方程创建椭圆

发布于 2024-10-17 00:40:21 字数 656 浏览 5 评论 0原文

我正在使用此函数，该函数将对象围绕完美圆的中心点移动，并尝试修改它以将其移动为椭圆形，高度为宽度的 1/2？

基本上，我有一个设定的速度

var myVelocity:Number = 0.25;

，然后根据速度计算正弦和余弦

var myCos:Number = Math.cos(myVelocity);
var mySin:Number = Math.sin(myVelocity);

，然后计算物体沿每个轴距固定中心点的距离，

var x1:Number = myBall.x - centerX;
var y1:Number = myBall.y - centerY;
var x2:Number = myCos * x1 - mySin * y1;
var y2:Number = myCos * y1 + mySin * x1;
myBall.x = centerX + x2;
myBall.y = centerY + y2;

我还有另一个函数根据 myBall.x 计算 x 和 y = 中心X + cos(角度) * 半径；将半径修改为椭圆形很容易，但是有没有一种简单的方法可以将上面的半径修改为椭圆形呢？我想这样做是为了提高代码效率并减少数学函数调用的数量

原文

I am working with this function that moves an object around a center point in a perfect circle and am trying to modify it to move it in an oval shape that is 1/2 as high as it is wide?

Basically, I have a set speed

var myVelocity:Number = 0.25;

then I calculate my Sine and Cosine based on the speed

var myCos:Number = Math.cos(myVelocity);
var mySin:Number = Math.sin(myVelocity);

then I figure the distance of the the object from a fixed center points along each axis and

var x1:Number = myBall.x - centerX;
var y1:Number = myBall.y - centerY;
var x2:Number = myCos * x1 - mySin * y1;
var y2:Number = myCos * y1 + mySin * x1;
myBall.x = centerX + x2;
myBall.y = centerY + y2;

I have another function that figures x and y based upon myBall.x = centerX + cos(angle) * radius; that is easy enough to modify the radius to become an ellipse, but is there an easy way to mod the one above to become an ellipse? I want to do this to be more efficient with the code and reduce the number of math function calls

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水波映月 2024-10-24 00:40:21

这个问题几乎逐字逐句地反映了 Keith Peters 在基础 Actionscript 3.0：让事物动起来！< /a>

我从书中为您摘录了一个快速片段。

import flash.display.Shape;
import flash.events.Event;

var box:Shape = new Shape();
box.graphics.beginFill(0xFF0000);
box.graphics.drawRect(0, 0, 50, 50);
box.graphics.endFill();
addChild(box);
var angle:Number = 0;
var centerX:Number = stage.stageWidth/2 - (box.width/2);
var centerY:Number = stage.stageHeight/2 - (box.height/2)
var radiusX:Number = 200;
var radiusY:Number = 100;
var speed:Number = .1;
stage.addEventListener(Event.ENTER_FRAME, loop, false, 0, true);

function loop(evt:Event):void
{
    box.x = centerX + Math.sin(angle) * radiusX;
    box.y = centerY + Math.cos(angle) * radiusY;
    angle += speed;
}

结果：http://www.swfupload.com/view/155573.htm

This question is nearly verbatim to what Keith Peters covers in Foundation Actionscript 3.0: Making Things Move!

I've whipped up a quick snippet for you from the book.

import flash.display.Shape;
import flash.events.Event;

var box:Shape = new Shape();
box.graphics.beginFill(0xFF0000);
box.graphics.drawRect(0, 0, 50, 50);
box.graphics.endFill();
addChild(box);
var angle:Number = 0;
var centerX:Number = stage.stageWidth/2 - (box.width/2);
var centerY:Number = stage.stageHeight/2 - (box.height/2)
var radiusX:Number = 200;
var radiusY:Number = 100;
var speed:Number = .1;
stage.addEventListener(Event.ENTER_FRAME, loop, false, 0, true);

function loop(evt:Event):void
{
    box.x = centerX + Math.sin(angle) * radiusX;
    box.y = centerY + Math.cos(angle) * radiusY;
    angle += speed;
}

Result: http://www.swfupload.com/view/155573.htm

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