/**
 * 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 geomVertexReader.h
 * @author drose
 * @date 2005-03-25
 */

#ifndef GEOMVERTEXREADER_H
#define GEOMVERTEXREADER_H

#include "pandabase.h"
#include "geomVertexData.h"
#include "geomVertexColumn.h"
#include "internalName.h"
#include "luse.h"
#include "pointerTo.h"

/**
 * This object provides a high-level interface for quickly reading a sequence
 * of numeric values from a vertex table.
 *
 * It is particularly optimized for reading a single column of data values for
 * a series of vertices, without changing columns between each number.
 * Although you can also use one GeomVertexReader to read across the columns
 * if it is convenient, by calling set_column() repeatedly at each vertex, it
 * is faster to read down the columns, and to use a different GeomVertexReader
 * for each column.
 *
 * Note that a GeomVertexReader does not keep a reference count to the actual
 * vertex data buffer (it grabs the current data buffer from the
 * GeomVertexData whenever set_column() is called).  This means that it is
 * important not to keep a GeomVertexReader object around over a long period
 * of time in which the data buffer is likely to be deallocated; it is
 * intended for making a quick pass over the data in one session.
 *
 * It also means that you should create any GeomVertexWriters *before*
 * creating GeomVertexReaders on the same data, since the writer itself might
 * cause the vertex buffer to be deallocated.  Better yet, use a
 * GeomVertexRewriter if you are going to create both of them anyway.
 */
class EXPCL_PANDA_GOBJ GeomVertexReader : public GeomEnums {
PUBLISHED:
  INLINE GeomVertexReader(Thread *current_thread = Thread::get_current_thread());
  INLINE GeomVertexReader(const GeomVertexData *vertex_data,
                          Thread *current_thread = Thread::get_current_thread());
  INLINE GeomVertexReader(const GeomVertexData *vertex_data,
                          CPT_InternalName name,
                          Thread *current_thread = Thread::get_current_thread());
  INLINE GeomVertexReader(const GeomVertexArrayData *array_data,
                          Thread *current_thread = Thread::get_current_thread());
  INLINE GeomVertexReader(const GeomVertexArrayData *array_data,
                          int column,
                          Thread *current_thread = Thread::get_current_thread());

public:
  INLINE GeomVertexReader(const GeomVertexDataPipelineReader *data_reader,
                          const InternalName *name,
                          bool force = true);

PUBLISHED:
  INLINE GeomVertexReader(const GeomVertexReader &copy);
  INLINE void operator = (const GeomVertexReader &copy);
  INLINE ~GeomVertexReader();

  INLINE const GeomVertexData *get_vertex_data() const;
  INLINE const GeomVertexArrayData *get_array_data() const;
  INLINE const GeomVertexArrayDataHandle *get_array_handle() const;
  INLINE size_t get_stride() const;
  INLINE Thread *get_current_thread() const;

  INLINE void set_force(bool force);
  INLINE bool get_force() const;

  INLINE bool set_column(int column);
  INLINE bool set_column(CPT_InternalName name);
  bool set_column(int array, const GeomVertexColumn *column);

  INLINE void clear();
  INLINE bool has_column() const;
  INLINE int get_array() const;
  INLINE const GeomVertexColumn *get_column() const;

  INLINE void set_row_unsafe(int row);
  INLINE void set_row(int row);

  INLINE int get_start_row() const;
  INLINE int get_read_row() const;
  INLINE bool is_at_end() const;

  INLINE float get_data1f();
  INLINE const LVecBase2f &get_data2f();
  INLINE const LVecBase3f &get_data3f();
  INLINE const LVecBase4f &get_data4f();
  INLINE LMatrix3f get_matrix3f();
  INLINE LMatrix4f get_matrix4f();

  INLINE double get_data1d();
  INLINE const LVecBase2d &get_data2d();
  INLINE const LVecBase3d &get_data3d();
  INLINE const LVecBase4d &get_data4d();
  INLINE LMatrix3d get_matrix3d();
  INLINE LMatrix4d get_matrix4d();

  INLINE PN_stdfloat get_data1();
  INLINE const LVecBase2 &get_data2();
  INLINE const LVecBase3 &get_data3();
  INLINE const LVecBase4 &get_data4();
  INLINE LMatrix3 get_matrix3();
  INLINE LMatrix4 get_matrix4();

  INLINE int get_data1i();
  INLINE const LVecBase2i &get_data2i();
  INLINE const LVecBase3i &get_data3i();
  INLINE const LVecBase4i &get_data4i();

  void output(std::ostream &out) const;

protected:
  INLINE GeomVertexColumn::Packer *get_packer() const;

private:
  void initialize();

  INLINE bool set_pointer(int row);
  INLINE void quick_set_pointer(int row);
  INLINE const unsigned char *inc_pointer();

  bool set_vertex_column(int array, const GeomVertexColumn *column,
                         const GeomVertexDataPipelineReader *data_reader);
  bool set_array_column(const GeomVertexColumn *column);

  // It is important that we only store *one* of the following two pointers.
  // If we are storing a GeomVertexDataarray index, we must not keep a pointer
  // to the particular ArrayData we are working on (if we do, it may result in
  // an extra copy of the data due to holding the reference count).
  CPT(GeomVertexData) _vertex_data;
  int _array;
  CPT(GeomVertexArrayData) _array_data;

  Thread *_current_thread;
  GeomVertexColumn::Packer *_packer;
  int _stride;

  CPT(GeomVertexArrayDataHandle) _handle;
  const unsigned char *_pointer_begin;
  const unsigned char *_pointer_end;
  const unsigned char *_pointer;

  int _start_row;
  bool _force;

#ifndef NDEBUG
  // This is defined just for the benefit of having something non-NULL to
  // return from a nassertr() call.
  static const unsigned char empty_buffer[100];
#endif
};

INLINE std::ostream &
operator << (std::ostream &out, const GeomVertexReader &reader) {
  reader.output(out);
  return out;
}

#include "geomVertexReader.I"

#endif