TEveTriangleSet.cxx

// @(#)root/eve:$Id$
// Authors: Matevz Tadel & Alja Mrak-Tadel: 2006, 2007

/*************************************************************************
 * Copyright (C) 1995-2007, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#include "TEveTriangleSet.h"
#include "TEveRGBAPalette.h"
#include "TEveManager.h"

#include "TMath.h"
#include "TVector3.h"
#include "TRandom3.h"


/** \class TEveTriangleSet
\ingroup TEve
Made from a list of vertices and a list of triangles (triplets of
vertex indices).

If input is composed from triangles with direct vertex coordinates
one should consider finding all occurrences of the same vertex
and specifying it only once.
*/

ClassImp(TEveTriangleSet);

////////////////////////////////////////////////////////////////////////////////
/// Constructor.

TEveTriangleSet::TEveTriangleSet(Int_t nv, Int_t nt, Bool_t norms, Bool_t cols) :
   TEveElementList("TEveTriangleSet", "", kTRUE),
   fNVerts  (nv), fVerts(0),
   fNTrings (nt), fTrings(0), fTringNorms(0), fTringCols(0)
{
   InitMainTrans();

   fVerts  = new Float_t[3*fNVerts];
   fTrings = new Int_t  [3*fNTrings];
   fTringNorms = (norms) ? new Float_t[3*fNTrings] : 0;
   fTringCols  = (cols)  ? new UChar_t[3*fNTrings] : 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Destructor.

TEveTriangleSet::~TEveTriangleSet()
{
   delete [] fVerts;
   delete [] fTrings;
   delete [] fTringNorms;
   delete [] fTringCols;
}

////////////////////////////////////////////////////////////////////////////////
/// Generate triangle normals via cross product of triangle edges.

void TEveTriangleSet::GenerateTriangleNormals()
{
   if (fTringNorms == 0)  fTringNorms = new Float_t[3*fNTrings];

   TVector3 e1, e2, n;
   Float_t *norm = fTringNorms;
   Int_t   *tring  = fTrings;
   for(Int_t t=0; t<fNTrings; ++t, norm+=3, tring+=3)
   {
      Float_t* v0 = Vertex(tring[0]);
      Float_t* v1 = Vertex(tring[1]);
      Float_t* v2 = Vertex(tring[2]);
      e1.SetXYZ(v1[0]-v0[0], v1[1]-v0[1], v1[2]-v0[2]);
      e2.SetXYZ(v2[0]-v0[0], v2[1]-v0[1], v2[2]-v0[2]);
      n = e1.Cross(e2);
      n.SetMag(1);
      n.GetXYZ(norm);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Assign random colors to all triangles.

void TEveTriangleSet::GenerateRandomColors()
{
   if (fTringCols == 0)  fTringCols = new UChar_t[3*fNTrings];

   TRandom r;
   r.SetSeed(0);
   UChar_t *col = fTringCols;
   for(Int_t t=0; t<fNTrings; ++t, col+=3)
   {
      col[0] = (UChar_t) r.Uniform(60, 255);
      col[1] = (UChar_t) r.Uniform(60, 255);
      col[2] = (UChar_t) r.Uniform(60, 255);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Generate triangle colors by the z-component of the normal.
/// Current palette is taken from gStyle.

void TEveTriangleSet::GenerateZNormalColors(Float_t fac, Int_t min, Int_t max,
                                            Bool_t interp, Bool_t wrap)
{
   if (fTringCols  == 0)  fTringCols = new UChar_t[3*fNTrings];
   if (fTringNorms == 0)  GenerateTriangleNormals();

   TEveRGBAPalette pal(min, max, interp, wrap);
   UChar_t *col = fTringCols;
   Float_t *norm = fTringNorms;
   for(Int_t t=0; t<fNTrings; ++t, col+=3, norm+=3)
   {
      Int_t v = TMath::Nint(fac * norm[2]);
      pal.ColorFromValue(v, col, kFALSE);
   }
   gEve->Redraw3D();
}

////////////////////////////////////////////////////////////////////////////////
/// Compute bounding box.
/// Virtual from TAttBBox.

void TEveTriangleSet::ComputeBBox()
{
   if (fNVerts <= 0) {
      BBoxZero();
      return;
   }

   BBoxInit();
   Float_t* v = fVerts;
   for (Int_t i=0; i<fNVerts; ++i, v += 3)
      BBoxCheckPoint(v);
}

////////////////////////////////////////////////////////////////////////////////
/// Paint this object. Only direct rendering is supported.

void TEveTriangleSet::Paint(Option_t*)
{
   PaintStandard(this);
}

////////////////////////////////////////////////////////////////////////////////
/// Read a simple ascii input file describing vertices and triangles.

TEveTriangleSet* TEveTriangleSet::ReadTrivialFile(const char* file)
{
   static const TEveException kEH("TEveTriangleSet::ReadTrivialFile ");

   FILE* f = fopen(file, "r");
   if (f == 0) {
      ::Error(kEH, "file '%s' not found.", file);
      return 0;
   }

   Int_t nv, nt;
   if (fscanf(f, "%d %d", &nv, &nt) != 2) {
      fclose(f);
      throw kEH + "Reading nv, nt failed.";
   }

   if (nv < 0 || nt < 0) {
      fclose(f);
      throw kEH + "Negative number of vertices / triangles specified.";
   }

   TEveTriangleSet* ts = new TEveTriangleSet(nv, nt);

   Float_t *vtx = ts->Vertex(0);
   for (Int_t i=0; i<nv; ++i, vtx+=3) {
      if (fscanf(f, "%f %f %f", &vtx[0], &vtx[1], &vtx[2]) != 3) {
         fclose(f);
         throw kEH + TString::Format("Reading vertex data %d failed.", i);
      }
    }

   Int_t *tngl = ts->Triangle(0);
   for (Int_t i=0; i<nt; ++i, tngl+=3) {
      if (fscanf(f, "%d %d %d", &tngl[0], &tngl[1], &tngl[2]) != 3) {
         fclose(f);
         throw kEH + TString::Format("Reading triangle data %d failed.", i);
      }
   }

   fclose(f);

   return ts;
}