fltMeshPrimitive.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file fltMeshPrimitive.cxx
 * @author drose
 * @date 2001-02-28
 */

#include "fltMeshPrimitive.h"
#include "fltRecordReader.h"
#include "fltRecordWriter.h"
#include "fltHeader.h"
#include "fltMaterial.h"

TypeHandle FltMeshPrimitive::_type_handle;

/**
 *
 */
FltMeshPrimitive::
FltMeshPrimitive(FltHeader *header) : FltBead(header) {
  _primitive_type = PT_tristrip;
}

/**
 * Fills in the information in this bead based on the information given in the
 * indicated datagram, whose opcode has already been read.  Returns true on
 * success, false if the datagram is invalid.
 */
bool FltMeshPrimitive::
extract_record(FltRecordReader &reader) {
  if (!FltBead::extract_record(reader)) {
    return false;
  }

  nassertr(reader.get_opcode() == FO_mesh_primitive, false);
  DatagramIterator &iterator = reader.get_iterator();

  _primitive_type = (PrimitiveType)iterator.get_be_int16();

  int vertex_width = iterator.get_be_int16();
  int num_vertices = iterator.get_be_int32();

  if (vertex_width == 1) {
    for (int i = 0; i < num_vertices; i++) {
      _vertices.push_back(iterator.get_uint8());
    }

  } else if (vertex_width == 2) {
    for (int i = 0; i < num_vertices; i++) {
      _vertices.push_back(iterator.get_be_uint16());
    }

  } else if (vertex_width == 4) {
    for (int i = 0; i < num_vertices; i++) {
      _vertices.push_back(iterator.get_be_int32());
    }

  } else {
    nout << "Invalid vertex width in mesh primitive: " << vertex_width
         << "\n";
    return false;
  }

  check_remaining_size(iterator);
  return true;
}

/**
 * Fills up the current record on the FltRecordWriter with data for this
 * record, but does not advance the writer.  Returns true on success, false if
 * there is some error.
 */
bool FltMeshPrimitive::
build_record(FltRecordWriter &writer) const {
  if (!FltBead::build_record(writer)) {
    return false;
  }

  writer.set_opcode(FO_mesh_primitive);
  Datagram &datagram = writer.update_datagram();

  datagram.add_be_int16(_primitive_type);

  // Determine the optimum index width, based on the largest vertex index.
  int max_index = 0;
  Vertices::const_iterator vi;
  for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
    max_index = std::max(max_index, (*vi));
  }

  int vertex_width;
  if (max_index < 0x100) {
    vertex_width = 1;
  } else if (max_index < 0x10000) {
    vertex_width = 2;
  } else {
    vertex_width = 4;
  }

  datagram.add_be_int16(vertex_width);
  datagram.add_be_int32(_vertices.size());

  if (vertex_width == 1) {
    for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
      datagram.add_uint8(*vi);
    }

  } else if (vertex_width == 2) {
    for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
      datagram.add_be_uint16(*vi);
    }

  } else {
    for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
      datagram.add_be_int32(*vi);
    }
  }

  return true;
}