• orgoton <orgoton mindless.com> Mar 06 2007

orgoton <orgoton mindless.com> writes:

Frits van Bommel Wrote:

 orgoton wrote:
 I have this
 
 struct Vertex{
 (...)
 float z;
 }
 
 then:
 Vertex vData[][];
 
 Somewhere later:
 vData.length=sizeX;
 foreach(Vertex strip[]; vData[]) strip.length=sizeY;


 foreach(inout Vertex[] strip; vData) strip.length = sizeY;
 or just:
 foreach(inout strip; vData) strip.length = sizeY;
 
 Note: only the inout is significant, the rest is just nitpicking :P.
 If you don't specify 'inout', you're just modifying a local copy of the 
 element...
 
 And IIRC something like "vData = new Vertex[][](sizeX, sizeY)" should 
 replace that entire code sequence, initializing the outer array to an 
 array of sizeX arrays of length sizeY.
 
 Here the array is initialized. So far, I think I haven't done anything
illegal. (SizeX and SizeY are runtime values, ushort vars). So first I say how
many strips I want, and next, I put in how many elements that strip will have.


 You haven't done anything illegal, just something wrong ;).
 You haven't initialized the array the way you thought you did: it's just 
 an array of _empty_ dynamic arrays at this point.
 
 ulong m;
 foreach (Vertex[] strip; vData)


 (this loop doesn't require 'inout' since the array itself isn't 
 modified, just the data it references)
 
 {
       foreach (Vertex vertex; strip)


 foreach(inout Vertex vertex; strip)
 (or: foreach(inout vertex; strip))
 
       {
            file.read(vertex.height);
            m++;
       }
 }
 
 Here I read the values from a file. First, I select a strip, and then go
through all the elements of that array and read their values. "m" is a counter
to see how many elements where read.
 
 The thing is, m=0 at the end of the loop. What did I do wrong?


 Since you didn't initialize the elements of vData, their lengths are all 
 still zero. So your inner loop is never executed.



That did it! Thanks a lot. I feel illuminated :P