A simple teapot isosurface

[DarkBeam]

I found the Utah teapot shader on Shadertoy but it looked way too complicated for me.
So I thought that it might be redesigned using far less constants, routines and stuff, of course using more simple shapes!
But it still looks pretty realistic.
The code reported here must be shadertoy-ized a little but the hardest work is done;

Code:

// Teapot lame isosurface code is released under CC BY-SA 3.0
// Original release 13-11-2016 by DarkBeam at Fractalforums
// all variables must be declared, and set to 0 
// (except x,y,z) at the beginning and must be public
// but I suggest to merge everything in an unique routine

DE {
  DEt = teabody();
  if (DEt >1.8) return DEt; // speedup
  DEx = min(spout(),handle());
  DEx = max(DEx,-teahole);
  DEt = min(DEx,DEt); // you might use a smooth min() here
  return max(DEt,-spouthole);
}


teabody {
   // Just some circles stitched together (more or less :P )
   r = x*x+y*y; r = sqrt(r);
   cut0=z-1.8;
   if (cut0>0.0) {
     xtp=r-.6145898;
     return sqrt(cut0*cut0+r*r)-.015;
   } else {
     cut2=2*r-z-0.1;
     cut2=max(cut2,-z+.8);
     if (cut2>0) {
       xtp=-r+.45;
       xtp=0.5*(xtp-abs(xtp));
       ztp=cut0+1.;
       xtp=xtp*xtp; ztp=ztp*ztp;
       w=sqrt(xtp+ztp)-.782623792;
     }else {
       xtp=r-0.95;ztp=cut0;
       xtp=xtp*xtp; ztp=ztp*ztp;
       w=sqrt(xtp+ztp)-.3354102; w = -w;
     }
     teahole=w;
     return abs(w)-.015;
     }   
}

spout {
  xtp = x-.94; ztp=z-.7;
  v = .707106 (xtp+ztp);  u = .707106 (xtp-ztp);
  // v*v causes DE trouble but not in this small interval
  // else modify the v multipliers
  t = sqrt(u*u+y*y*1.6)-.3+.311*v-.12*(v*v);
  t = max (t,abs(v-.7)-.7 );
  spouthole = t;
  t = abs(t-.015)-.015);
  t = max (t,z-1.5 );
  return t;
}

handle {
   cut0=z-1.21;
   if (cut0>0.0) {
     xtp=x+1.11; xtp=xtp*xtp;
     ztp=cut0*cut0;
     w=sqrt(xtp+ztp)-.3354102;
   } else {
     xtp=x+0.6; xtp=xtp*xtp;
     ztp=cut0*cut0;
     w=sqrt(xtp+ztp)-.9454102;
   }
   return sqrt(w*w+y*y)-.1; 
}

[M Benesi]

  Good job Luca!

  initialize variables somewhere? 

[DarkBeam]

Thanks Matthew but let me attach a preview

[M Benesi]

Looks like texture is not attached to normals on the object, but instead to something else?  First one is nice!

[DarkBeam]

Well I don't know it is a mb3d lightmap (the actual iso is clean) the second is a cut view that shows the inside and the holes all around
Also yes all vars are float and you must declare and initialize them!
I programmed all in assembly (where vars ... don't exist  ) this is a transcript that hopefully is not too messy!!!

[Sabine]

You did it, Luca!!! You're my hero