Conversion of spherical coordinates to cartesian coordinates code Heliostat

[sroy10]

Hi,

Could someone please explain the below code to me. This is part of a heliostat code written by Jremington. Why do we have '*' before ele and az (which stands for elevation and azimuth)

Basically, I am trying to understand the code for the conversion of spherical coordinates to cartesian coordinates

void xyz_to_eleAz(float * ele, float * az, float xyz[3]){
  float rtd = 180.0 / PI;
  
  float v[3], m = 0;
  // normalize input vector
  for (byte i = 0; i < 3; i++)
    m = m + (xyz[i] * xyz[i]);
    m = sqrt(m);
  
  for (byte i = 0; i < 3; i++) 
   v[i] = xyz[i] / m;
   float t = rtd * atan2(v[0], v[1]);
     if (t < 0.0) {
        t = t + 360.0; //compass wrap
      }
  *az = t;
  *ele = rtd * asin(v[2]);

If anyone could also suggest the formula or code required to write create the conversion. Why are we normalising the data?

[anon73444976]

@sroy10

Why do we have '*' before ele and az (

To dereference the pointers.
To return the values to the caller

Applying the IDE's auto format tool to the code would make the code easier to understand and visualise

[lastchancename]

You could ask @jremington !

[anon73444976]

Your requests for explanation are coming across really badly as excuses for plagiarism.

Dereferencing was explained on your other topic about this code.

[alto777]

It's the same as your earlier post.

You need learn about arrays, pointers, dereferencing and call by reference.

Srsly, you don't want to have to come here every time a little bit of C/C++ is outside your experience.

You'll get tired of that. So might we.

a7

[jremington]

@sroy10 Do not cross post.

Why are we normalising the data?

Very basic trigonometry: look up the concepts of "unit circle" and "unit sphere".