geomPatches.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 geomPatches.cxx
 * @author drose
 * @date 2012-04-27
 */

#include "geomPatches.h"
#include "geomVertexRewriter.h"
#include "pStatTimer.h"
#include "bamReader.h"
#include "bamWriter.h"
#include "graphicsStateGuardianBase.h"

TypeHandle GeomPatches::_type_handle;

/**
 * The number of vertices per patch must be specified to the GeomPatches
 * constructor, and it may not be changed during the lifetime of the
 * GeomPatches object.  Create a new GeomPatches if you need to have a
 * different value.
 */
GeomPatches::
GeomPatches(int num_vertices_per_patch, GeomPatches::UsageHint usage_hint) :
  GeomPrimitive(usage_hint),
  _num_vertices_per_patch(num_vertices_per_patch)
{
}

/**
 *
 */
GeomPatches::
GeomPatches(const GeomPatches &copy) :
  GeomPrimitive(copy),
  _num_vertices_per_patch(copy._num_vertices_per_patch)
{
}

/**
 *
 */
GeomPatches::
~GeomPatches() {
}

/**
 *
 */
PT(GeomPrimitive) GeomPatches::
make_copy() const {
  return new GeomPatches(*this);
}

/**
 * Returns the fundamental rendering type of this primitive: whether it is
 * points, lines, or polygons.
 *
 * This is used to set up the appropriate antialiasing settings when
 * AntialiasAttrib::M_auto is in effect; it also implies the type of primitive
 * that will be produced when decompose() is called.
 */
GeomPrimitive::PrimitiveType GeomPatches::
get_primitive_type() const {
  return PT_patches;
}

/**
 * If the primitive type is a simple type in which all primitives have the
 * same number of vertices, like patches, returns the number of vertices per
 * primitive.  If the primitive type is a more complex type in which different
 * primitives might have different numbers of vertices, for instance a
 * triangle strip, returns 0.
 *
 * In the case of GeomPatches, this returns the fixed number that was
 * specified to the constructor.
 */
int GeomPatches::
get_num_vertices_per_primitive() const {
  return _num_vertices_per_patch;
}

/**
 * Calls the appropriate method on the GSG to draw the primitive.
 */
bool GeomPatches::
draw(GraphicsStateGuardianBase *gsg, const GeomPrimitivePipelineReader *reader,
     bool force) const {
  return gsg->draw_patches(reader, force);
}

/**
 * Tells the BamReader how to create objects of type Geom.
 */
void GeomPatches::
register_with_read_factory() {
  BamReader::get_factory()->register_factory(get_class_type(), make_from_bam);
}

/**
 * Writes the contents of this object to the datagram for shipping out to a
 * Bam file.
 */
void GeomPatches::
write_datagram(BamWriter *manager, Datagram &dg) {
  GeomPrimitive::write_datagram(manager, dg);
  dg.add_uint16(_num_vertices_per_patch);
}

/**
 * This internal function is called by make_from_bam to read in all of the
 * relevant data from the BamFile for the new GeomPatches.
 */
void GeomPatches::
fillin(DatagramIterator &scan, BamReader *manager) {
  GeomPrimitive::fillin(scan, manager);
  _num_vertices_per_patch = scan.get_uint16();
}

/**
 * This function is called by the BamReader's factory when a new object of
 * type Geom is encountered in the Bam file.  It should create the Geom and
 * extract its information from the file.
 */
TypedWritable *GeomPatches::
make_from_bam(const FactoryParams &params) {
  GeomPatches *object = new GeomPatches(0, UH_unspecified);
  DatagramIterator scan;
  BamReader *manager;

  parse_params(params, scan, manager);
  object->fillin(scan, manager);

  return object;
}