REveRenderData.cxx

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// @(#)root/eve7:$Id$
// Authors: Matevz Tadel & Alja Mrak-Tadel: 2006, 2007, 2018
 
/*************************************************************************
 * Copyright (C) 1995-2019, 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 <ROOT/REveRenderData.hxx>
#include <ROOT/REveUtil.hxx>
 
#include <cstdio>
#include <cstring>
 
using namespace ROOT::Experimental;
 
/////////////////////////////////////////////////////////////////////////////////////////
/// Constructor
 
REveRenderData::REveRenderData(const std::string &func, int size_vert, int size_norm, int size_idx) :
   fRnrFunc(func)
{
   Reserve(size_vert, size_norm, size_idx);
}
 
/////////////////////////////////////////////////////////////////////////////////////////
/// Reserve place for render data
 
void REveRenderData::Reserve(int size_vert, int size_norm, int size_idx)
{
   if (size_vert > 0)
      fVertexBuffer.reserve(size_vert);
   if (size_norm > 0)
      fNormalBuffer.reserve(size_norm);
   if (size_idx > 0)
      fIndexBuffer.reserve(size_idx);
}
 
/////////////////////////////////////////////////////////////////////////////////////////
/// Write render data to binary buffer
 
int REveRenderData::Write(char *msg, int maxlen)
{
   static const REveException eh("REveRenderData::Write ");
 
   int off{0};
 
   auto append = [&](void *buf, int len) {
      if (off + len > maxlen)
         throw eh + "output buffer does not have enough memory";
      memcpy(msg + off, buf, len);
      off += len;
   };
 
   if (!fVertexBuffer.empty())
      append(&fVertexBuffer[0], fVertexBuffer.size() * sizeof(float));
 
   if (!fNormalBuffer.empty())
      append(&fNormalBuffer[0], fNormalBuffer.size() * sizeof(float));
 
   if (!fIndexBuffer.empty())
      append(&fIndexBuffer[0], fIndexBuffer.size() * sizeof(int));
 
   return off;
}
 
/////////////////////////////////////////////////////////////////////////////////////////
/// Calculate texture dimensions to hold nel elements with given alignment on x axis.
/// Static function.
///
/// Implementation could be improved -- now it simply goes for near-square-root(size)
/// dimensions that satisfy the alignment requirement. 
 
void REveRenderData::CalcTextureSize(int nel, int align, int &sx, int &sy)
{
   if (nel <= 0) { sx = sy = 0; return; }
 
   sx = (int) std::ceil(std::sqrt(nel));
   int rx = sx % align;
   if (rx > 0) sx += align - rx;
   sy = nel / sx;
   if (nel % sx > 0) sy += 1;
}