InitializeGrid中的错误在哪里？它返回错误的索引

Question

好了，我正在尝试编写一个矩形，其中包含多个连接在一起的三角形条带。根据：http://www.corehtml5.com/trianglestripfundamentals.php

当您有多行时，您需要处理环绕的三角形。然而，在我的代码示例中使用建议的算法，我得到了不正确的indice结果。

下面是我的示例，其中包含输出。

我尝试了复制/粘贴建议的算法，但它似乎没有返回正确的结果。

// Create the Index Points for the buffer array.
var rows=2;
var cols=3;
var grid = rows*cols;
var offset;
var pos = [];
var index = 0;
var mpOffset = 1;
for (var row = 0; row <= rows; ++row)
{
  offsetY = row * (mpOffset / rows);
  for (var col = 0; col <= cols; ++col)
  {
    offsetX = col * (mpOffset / cols);

    pos[index+0] = (offsetX);
    pos[index+1] = (offsetY);
    index+=2;
  }
}
log.info("pos="+JSON.stringify(pos)); //  <-- Correct working good.
log.info("pos.length="+pos.length);

function initializeGrid(cols,rows)
{
    var trianglestrip = [];
    var RCvertices=2*cols*(rows-1);
    var TSvertices=2*cols*(rows-1)+2*(rows-2);
    var numVertices=TSvertices;
    var j=0;
    for(var i = 1; i <= RCvertices; i += 2)
    {
        trianglestrip[ j ] = (1 +i)/2;
        trianglestrip[ j +1 ] = (cols*2 + i + 1) / 2;
        if( trianglestrip[ j +1 ] % cols == 0) 
        {
            if( trianglestrip[ j +1 ] != cols && trianglestrip[ j +1 ] != cols*rows )
            {
                trianglestrip[ j +2 ] = trianglestrip[ j +1 ];
                trianglestrip[ j +3 ] = (1 + i + 2) / 2;
                j += 2; 
            }
        }
        j += 2;
    }
    return trianglestrip;
}

var triStrip = initializeGrid(cols,rows);
log.info("triStrip="+JSON.stringify(triStrip)); // <-- Bad Not working.
log.info("triStrip.length="+triStrip.length);

// Generating the actual Point strip.
var actualStrip = [];
for (var i = 0 ; i < triStrip.length; ++i)
{
    actualStrip.push(pos[(triStrip[i]-1)*2+0]);
    actualStrip.push(pos[(triStrip[i]-1)*2+1]);
}
log.info("actualStrip="+JSON.stringify(actualStrip));
log.info("actualStrip.length="+actualStrip.length);

指标应为: 1，5，2，6，3，7，4，8，8，5，5，9，6，10，7，11，8，12

Answer 1

我最终重新创建了计算三角形条带指数的函数。还没有完全测试它，但它可以在网站上的示例中重新创建3x2网格。

代码如下：

// This calculates the triangle points in a rectangular triangle strip.
// Used for 3D Webgl texture mapping.
// Copyright Joshua Langley 2019.
var rows=2;
var cols=3;
var grid = rows*cols;
var offset;
var pos = [];
var index = 0;
var mpOffset = 1;
var offsetX, offsetY;
for (var row = 0; row <= rows; ++row)
{
  offsetY = row * (mpOffset / rows);
  for (var col = 0; col <= cols; ++col)
  {
    offsetX = col * (mpOffset / cols);

    pos[index+0] = (offsetX);
    pos[index+1] = (offsetY);
    index+=2;
  }
}
log.info("pos="+JSON.stringify(pos));
log.info("pos.length="+pos.length);

var rows=rows+1,cols=cols+1; // Important this counting Points not Squares.
var grid = rows*cols;
var offset;
var indices = [];
var indice = 0;
var offset;
var doublePoints = false;
var tPoint, bPoint;
for (var row = 0; row < rows; ++row)
{ 
  for (var col = 0; col < (cols-1); ++col)
  {
      offset = row * rows + col;
      tPoint = offset+1;
      bPoint = offset+cols+1;

      if (bPoint > grid)
          continue;

      indices.push(tPoint);           
      indices.push(bPoint);
      if (offset > 0 && (bPoint+1) < grid && (offset+1) % cols == 0)
      {
          indices.push(bPoint);
          indices.push(tPoint+1);
      }                   
  }
}
log.info("indices="+JSON.stringify(indices)); // Expected Result
log.info("indices.length="+indices.length);

var actualStrip = [];
for (var i = 0 ; i < indices.length; ++i)
{
    actualStrip.push(pos[(indices[i]-1)*2+0]);
    actualStrip.push(pos[(indices[i]-1)*2+1]);
}
log.info("actualStrip="+JSON.stringify(actualStrip));
log.info("actualStrip.length="+actualStrip.length);