Warning: file_get_contents(/data/phpspider/zhask/data//catemap/3/html/83.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Javascript 从角度矩形的尺寸和位置查找顶点_Javascript_Html_Canvas_Vector - Fatal编程技术网

Javascript 从角度矩形的尺寸和位置查找顶点

Javascript 从角度矩形的尺寸和位置查找顶点,javascript,html,canvas,vector,Javascript,Html,Canvas,Vector,我正在尝试实现转换矩阵公式: cos()-sin() sin()cos() 在下面的Javascript代码中,this.rot.cos=角度的cos,this.rot.sin是角度的sin var h1 = this.rot.cos * this.dimension.x, h2 = this.rot.sin * this.dimension.x, h3 = this.rot.cos * this.dimension.y, h4 = this.rot.sin * this.dimension.y

我正在尝试实现转换矩阵公式:

cos()-sin()

sin()cos()

在下面的Javascript代码中,this.rot.cos=角度的cos,this.rot.sin是角度的sin

var h1 = this.rot.cos * this.dimension.x,
h2 = this.rot.sin * this.dimension.x,
h3 = this.rot.cos * this.dimension.y,
h4 = this.rot.sin * this.dimension.y;

v = [

{
  x: h1 - h4,
  y: h2 + h3
},

{
  x: -(h1 - h4),
  y: h2 + h3
},

{
  x: -(h1 - h4),
  y: -(h2 + h3)
},

{
  x: h1 - h4,
  y: -(h2 + h3)
}

  ];

 tankBattle.ctx.beginPath();
  tankBattle.ctx.moveTo(v[0].x, v[0].y);
  tankBattle.ctx.lineTo(v[1].x, v[1].y);
  tankBattle.ctx.lineTo(v[2].x, v[2].y);
  tankBattle.ctx.lineTo(v[3].x, v[3].y);
  tankBattle.ctx.lineTo(v[0].x, v[0].y);

我得到的形状以与正弦波和余弦波相同的模式移动,并在一定程度上变成0(我相信是90和270)。这里的顶点计算有什么不对吗?

您的公式似乎有误,以下是有效的:


我不确定你想在哪个轴上旋转,但这个轴可能会有帮助。他们为我工作,不幸的是我不再有我写的脚本。在x轴和y轴上?这是正确的,非常感谢。我想知道自己哪里出了错,真是疯了。
function drawTank(x, y, rot)  {

    var cosrot = Math.cos(rot);
    var sinrot = Math.sin(rot);

    var h1 = cosrot * dimension.x,
        h2 = sinrot * dimension.x,
        h3 = cosrot * dimension.y,
        h4 = sinrot * dimension.y;

    v = [{
        x: h1 - h4,
        y: h2 + h3
    },

    {
        x: h1 + h4,
        y: h2 - h3
    },

    {
        x: -h1 + h4,
        y: -h2 - h3
    },

    {
        x: -h1 - h4,
        y: -h2 + h3
    }];

    ctx.save();
    ctx.translate(x, y);
    ctx.beginPath();
    ctx.moveTo(v[0].x, v[0].y);
    ctx.lineTo(v[1].x, v[1].y);
    ctx.lineTo(v[2].x, v[2].y);
    ctx.lineTo(v[3].x, v[3].y);
    ctx.lineTo(v[0].x, v[0].y);
    ctx.stroke();
    ctx.restore();
}