为什么我的变量“ j”未定义？

Question

我有一个使用Three.js为3D对象着色的功能。 我的变量j存在，如果我使用alert(j)它可以工作，但是当我使用变量作为数组（颜色图）的索引时，它不起作用。

colormap=[[0,0,0.5625],[0,0,0.625],[0,0,0.6875],[0,0,0.75],[0,0,0.8125],[0,0,0.875],[0,0,0.9375],[0,0,1],[0,0.0625,1],[0,0.125,1],[0,0.1875,1],[0,0.25,1],[0,0.3125,1],[0,0.375,1],[0,0.4375,1],[0,0.5,1],[0,0.5625,1],[0,0.625,1],[0,0.6875,1],[0,0.75,1],[0,0.8125,1],[0,0.875,1],[0,0.9375,1],[0,1,1],[0.0625,1,0.9375],[0.125,1,0.875],[0.1875,1,0.8125],[0.25,1,0.75],[0.3125,1,0.6875],[0.375,1,0.625],[0.4375,1,0.5625],[0.5,1,0.5],[0.5625,1,0.4375],[0.625,1,0.375],[0.6875,1,0.3125],[0.75,1,0.25],[0.8125,1,0.1875],[0.875,1,0.125],[0.9375,1,0.0625],[1,1,0],[1,0.9375,0],[1,0.875,0],[1,0.8125,0],[1,0.75,0],[1,0.6875,0],[1,0.625,0],[1,0.5625,0],[1,0.5,0],[1,0.4375,0],[1,0.375,0],[1,0.3125,0],[1,0.25,0],[1,0.1875,0],[1,0.125,0],[1,0.0625,0],[1,0,0],[0.9375,0,0],[0.875,0,0],[0.8125,0,0],[0.75,0,0],[0.6875,0,0],[0.625,0,0],[0.5625,0,0],[0.5,0,0]];

j = 0;// indice colore nella matrice

var callbackMale = function ( geometry, materials ) 
{
  // surf contain surface
  var cmin=surf.min(), cmax=surf.max(), colorLength=colormap.length;

  for ( var i = 0, l = geometry.vertices.length; i < l; i ++ ) 
  {

     var face = geometry.faces[ i ];
     j = Math.round(((surf[i]-cmin)/(cmax-cmin)*colorLength));

     if(j < 0) 
      j=0;
     else if( j >= colorLength) 
       j=colorLength;
     alert(j)
     var ind = colormap[j]; // j undefined              
     for(var k = 0 ; k < 3 ; k++)
     {              
       face.vertexColors[ k ] = new THREE.Color().setRGB(ind[0],ind[1],ind[2]);                 
     }//fine for interno

  }//fine for esterno
}

Answer 1

j的类型是什么？ 是int还是float或其他？ 我认为您尝试将浮点数放入int中，但这是行不通的。

Answer 2

您的循环将超出数组的范围，从而导致来自colormap[j]未定义值。

else if( j >= colorLength) 
    j=colorLength;

因为数组是从零开始的，所以将值放在数组的边界。 将最大值固定为低一：

else if( j >= colorLength) 
    j=colorLength-1;