Hi list,

I'm trying to use a density file in povray for the first time and the page is
always blank.

I use an external program to generate a file data.dat which looks like this,

10 10 10
0 0 0 240
1 0 0 240
2 0 0 240
3 0 0 240
4 0 0 240
5 0 0 240
6 0 0 240
7 0 0 240
8 0 0 240
etc ...

where the first line gives the dimensions, the first three columns are xyz
coordinates and last column the density value.

I use the c++ code posted here to create a df3 file. OK so far, I think.
Unfortunately, my basic example shows a blank page with nothing in it. I don't
know if the df3 file is incorrect or if it's a problem with the povray file
below,


background { color rgb <1.0,1.0,1.0> }
global_settings {
ambient_light <0.3,0.3,0.3>
}

#include "colors.inc"
#include "textures.inc"

light_source{<10,10,-10> color White}
#declare dist = 1.5;


camera {location <dist , dist ,dist>
right <0, 4/3, 0>
 up    <0,0,1>
 look_at  <0.0 , 0.0 , 0.0>}


#declare theinterior = interior {
   media {
      density {
         density_file df3 "data.df3"
         interpolate 1
         color_map {
            [0.00 rgb <0,0,0>]
            [0.2 rgb <0,0,1>]
            [0.4 rgb <0,1,0>]
            [1.00 rgb <1,0,0>]
         }
      }
   }
}

box {
   <0,0,0>, <1,1,1>
   pigment { rgbf 1 }
   interior { theinterior }
   hollow
}


I'll appreciate any advice.

Regards,

baptiste



Warp <war### [at] tagpovrayorg> wrote:
> Woody <nomail@nomail> wrote:
> > If you every have a few moments do you think you could modify the source code
> > you posted at http://news.povray.org/4799ff49%40news.povray.org, so that it can
> > take one or more *.txt files specified in the command line (instead of the
> > testdata.txt) and output them into df3 format with the same name (except for
> > the txt extension).
>
>   You mean with the same input file format?
>   How about this:
>
>
> #include <iostream>
> #include <fstream>
> #include <vector>
> #include <string>
> #include <cstdio>
>
> int main(int argc, char* argv[])
> {
>     // Limit the size of the df3 dimensions (safeguard against invalid input).
>     // Maximum df3 size will be SIZE_LIMIT*SIZE_LIMIT*SIZE_LIMIT.
>     const size_t SIZE_LIMIT = 256;
>
>     if(argc < 2)
>     {
>         std::cout << "Usage: " << argv[0] << " <files>\n";
>         return 0;
>     }
>
>     for(int i = 1; i < argc; ++i) // for each input file
>     {
>         std::ifstream is(argv[i]);
>         if(!is.good())
>         {
>             std::cerr << "Couldn't open ";
>             std::perror(argv[i]);
>             continue;
>         }
>
>         size_t xSize, ySize, zSize;
>         is >> xSize >> ySize >> zSize;
>         if(xSize > SIZE_LIMIT || ySize > SIZE_LIMIT || zSize > SIZE_LIMIT)
>         {
>             std::cout << "Skipping " << argv[i] << " (invalid input)\n";
>             continue;
>         }
>
>         std::vector<char> data(xSize*ySize*zSize + 6, 0);
>
>         // Setup df3 header:
>         data[0] = xSize/256; data[1] = xSize%256;
>         data[2] = ySize/256; data[3] = ySize%256;
>         data[4] = zSize/256; data[5] = zSize%256;
>
>         // Read input data and create df3 data:
>         while(true)
>         {
>             size_t x, y, z, value;
>             is >> x >> y >> z >> value;
>             if(!is.good()) break;
>             const size_t ind = x + y*xSize + z*xSize*ySize + 6;
>             if(ind < data.size())
>                 data[ind] = char(value);
>         }
>
>         // Write df3 file:
>         std::string filename = argv[i];
>         size_t ind = filename.find_last_of('.');
>         if(ind != filename.npos) filename.resize(ind);
>         filename += ".df3";
>         std::ofstream os(filename.c_str(), std::ios::binary);
>         os.write(&data[0], data.size());
>         std::cout << argv[i] << " -> " << filename << std::endl;
>     }
> }

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