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我正在尝试将一些代码从处理转换为 POVray 格式。这是原文：

http://www.openprocessing.org/sketch/17344

这是我创建的 POVray 版本：

#declare TWO_PI = 2 * pi;
#declare iNx = 32;      // the number of "horizontal" lines per charge, not taking into account iXmin
#declare iNy = 32;      // the number of "vertical" lines per charge
#declare iXmin = 24;        // size of the empty hole for each charge, measured in "horizontal" lines
#declare iSym = 5;      // number of charges arranged around the origin
#declare iSx = 2;
#declare iSy = 2;
#declare fMouseY = 300;     // need to get rid of this
#declare bLines = true; // show lines connecting the points
#declare bInside = true;    // are the curved lines inside or outside of the reference shape? or, are the charges inside or outside the reference shape?


#macro mag(fX, fY)
    dist(fX, fY, 0, 0)
#end

#macro dist(fX1, fY1, fX2, fY2)
    sqrt(pow(fX2 - fX1, 2) + pow(fY2 - fY1, 2))
#end


#macro calc()
    #local fY1 = 0;
    #local fX1 = 0;
    #local fX2 = exp(fX1) * cos(fY1);
    #local fY2 = exp(fX1) * sin(fY1) + fMouseY;
    #if (bInside)
        #local fD = pow(mag(fX2, fY2),  1/iSym);
    #else
        #local fD = pow(mag(fX2, fY2), -1/iSym);
    #end
    #local fArg = atan2(fX2, fY2) * -1/iSym;
    #local fX3 = fD * cos(fArg)/TWO_PI;
    #local fY3 = fD * sin(fArg)/TWO_PI;
    vlength(<fX3, fY3, 0,>) // return
#end

#macro draw()
    #for (i, 0, iNy - 1)
        #local fY = i * TWO_PI/iNy;
        #for (j, iXmin * iSx, iNx * iSx - 1)
            #local fX1 = j * TWO_PI/iNx/iSx;
            #local fX2 = (j + 1) * TWO_PI/iNx/iSx;
            lines(fn(fX1, fY), fn(fX2, fY))
        #end
    #end
    #for (i, iXmin, iNx)
        #local fX = i * TWO_PI/iNx;
        #for (j, 0, iNy * iSy - 1)
            #local fY1 = j * TWO_PI/iNy/iSy;
            #local fY2 = (j + 1) * TWO_PI/iNy/iSy;
            lines(fn(fX, fY1), fn(fX, fY2))
        #end
    #end
#end

#macro lines(aP1, aP2)
    #for (i, 0, iSym - 1)
        #local fX1 = aP1[i][0];
        #local fY1 = aP1[i][2];
        #local fX2 = aP2[i][0];
        #local fY2 = aP2[i][3];
        sphere
        {
            <fX1, fY1, 0,>/calc(),
            0.005
            pigment {color rgb x}
        }
        #if (bLines)
            cylinder
            {
                <fX1, fY1, 0,>/calc(),
                <fX2, fY2, 0,>/calc(),
                0.005
                pigment {color rgb x}
            }
        #end
    #end
#end

// this is where the magic happens ...

#macro fn(fX, fY)
    #local aP = array[iSym][2];
    #local fX1 = exp(fX) * cos(fY);
    #local fY1 = exp(fX) * sin(fY) - fMouseY;
    #if (bInside)
        #local fD = pow(mag(fX1, fY1),  1/iSym);
    #else
        #local fD = pow(mag(fX1, fY1), -1/iSym);
    #end
    #local fArg = atan2(fX1, fY1) * -1/iSym;
    #for (i, 0, iSym - 1)
        #local fX2 = fD * cos(fArg + i * TWO_PI/iSym);
        #local fY2 = fD * sin(fArg + i * TWO_PI/iSym);
        #local aP[i][0] = fX2/TWO_PI;
        #local aP[i][4] = fY2/TWO_PI;
    #end
    aP  //return
#end

draw()

然而，结果在一方面被打破了。当它们应该遵循平滑曲线时，现在有线条纵横交错。看：

纵横交错的线

我看了又看，找不到我做错了什么。我怀疑某些三角函数（例如 atan2）在两种语言中的行为不同。也许一种语言不能处理大于 2 * pi 的输入？

那可能吗？否则我不知道，希望能得到一些帮助。

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