在立方体中绘制实体三角形会导致闪烁

Question

我试图使用软件渲染绘制一个立方体。所以我用三角形绘制了一个立方体。所以我渲染一个实心三角形。立方体成功渲染，但旋转时闪烁。

这是我的实心三角形填充，有人会注意算法中的问题吗？

void Rasterizer::DrawSolidTriangle(int x0, int y0, int x1, int y1, int x2, int y2, Color&color)
{
    // Sort our points into order of y
    // 0 top
    // 2 middle
    // 1 bottom
    if (y1 < y0)
    {
        swap(y1, y0);
        swap(x1, x0);
    }
    if (y2 < y0)
    {
        swap(y2, y0);
        swap(x2, x0);
    }
    if (y1 < y2)
    {
        swap(y2, y1);
        swap(x2, x1);
    }

    float xl_edge = (float)x0;  // left edge
    float xr_edge = (float)x0;  // right edge

    float dxldy;
    float dxrdy;

    float dxdy1 = (float)(x2 - x0) / (y2 - y0);
    float dxdy2 = (float)(x1 - x0) / (y1 - y0);

    if (dxdy1 < dxdy2)
    {
        dxldy = dxdy1;
        dxrdy = dxdy2;
    }
    else
    {
        dxldy = dxdy2;
        dxrdy = dxdy1;
    }


    // Top of the triangle
    for (int y = y0; y<y2; y++)
    {

        for (int x = xl_edge; x<xr_edge; x++)
        {
            SetPixel((unsigned int)x, (unsigned int)y, color);

        }//end for loop x

        xl_edge = xl_edge + dxldy;
        xr_edge = xr_edge + dxrdy;

    }// end for loop y


    // Bottom half of the triangle

    if (dxdy1 < dxdy2)
    {
        dxldy = (float)(x2 - x1) / (y2 - y1);
    }
    else
    {
        dxrdy = (float)(x2 - x1) / (y2 - y1);
    }


    for (int y = y2; y<y1; y++)
    {

        for (int x = xl_edge; x<xr_edge; x++)
        {
            SetPixel((unsigned int)x, (unsigned int)y, color);
        }//end for loop x

        xl_edge = xl_edge + dxldy;
        xr_edge = xr_edge + dxrdy;

    }// end for loop y

} 

这是问题的截图，当旋转立方体这么慢时它会出现在这里：