c++ - 无需PCL（点云库）读写pcd文件

Question

我正在尝试编写一个在没有PCD（点云库）的情况下读写PCL文件的程序，我可以毫无问题地读取每个点的位置，但是RGB值是用uint32_t写的，我不知道如何阅读这种格式并将其转换为 RGB 值。

# .PCD v0.7 - Point Cloud Data file format
VERSION 0.7
FIELDS x y z rgb
SIZE 4 4 4 4
TYPE F F F F
COUNT 1 1 1 1
WIDTH 100
HEIGHT 1
VIEWPOINT 0 0 0 1 0 0 0
POINTS 100
DATA ascii
-0.031568773 -0.99000001 0.99000013 2.3418052e-038
0.031568673 -0.98999995 0.99000013 2.3418052e-038
-0.031568974 -0.54999995 0.77000004 2.3418052e-038
0.031568889 -0.54999995 0.77000004 2.3418052e-038

将最后一个值 (2.3418052e-038) 转换为 RGB 值？

没有点云库有没有办法做到这一点？

谢谢你。

Answer 1

请阅读以下来自维基百科的 PLY 格式数据，

https://en.wikipedia.org/wiki/PLY_(file_format)

添加示例片段以编写 PLY 文件，

std::string fname = "sample.ply";
std::ofstream out(fname);
out << "ply\n";
out << "format ascii 1.0\n";
out << "comment\n";
out << "element vertex " << cloud5->points.size() << "\n";
out << "property float" << sizeof(float) * 8 << " x\n";
out << "property float" << sizeof(float) * 8 << " y\n";
out << "property float" << sizeof(float) * 8 << " z\n";
out << "property uchar red\n";
out << "property uchar green\n";
out << "property uchar blue\n";
out << "property list uchar int vertex_indices\n";
out << "end_header\n";
out.close();

out.open(fname, std::ios_base::app);
for (size_t i = 0; i < cloud5->points.size(); ++i)
{
    out << cloud5->points[i].x << " " << cloud5->points[i].y << " " << cloud5->points[i].z << " " << (int)cloud5->points[i].r 
        << " " << (int)cloud5->points[i].g << " " << (int)cloud5->points[i].b << "\n";
}
out.close();