PathWalker Class Reference

A walker that travels along a path. More...

#include <path_walker.hpp>

List of all members.

Public Member Functions
	PathWalker (const Path *path, bool running=true)
virtual	~PathWalker ()
virtual Vector	advance (float elapsed_time)
	advances the path walker on the path and returns its new position
Vector	get_pos ()
	current position of path walker
void	goto_node (int node_no)
	advance until at given node, then stop
void	start_moving ()
	start advancing automatically
void	stop_moving ()
	stop advancing automatically
bool	is_moving ()
	returns true if PathWalker is currently moving
Public Attributes
const Path *	path
Private Member Functions
void	advance_node ()
void	goback_node ()
	PathWalker (const PathWalker &)
PathWalker &	operator= (const PathWalker &)
Private Attributes
bool	running
	set to false to immediately stop advancing
size_t	current_node_nr
size_t	next_node_nr
int	stop_at_node_nr
	stop advancing automatically when this node is reached
float	node_time
	the position between the current node and the next node as fraction between 0 and 1
float	node_mult
float	walking_speed

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Detailed Description

A walker that travels along a path.

Definition at line 27 of file path_walker.hpp.

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Constructor & Destructor Documentation

PathWalker::PathWalker	(	const Path *	path,
		bool	running = true
	)

Definition at line 22 of file path_walker.cpp.

References next_node_nr, node_mult, Path::nodes, and path.

                                                     :
  path(path), 
  running(running), 
  current_node_nr(0), 
  next_node_nr(0), 
  stop_at_node_nr(running?-1:0), 
  node_time(0),
  node_mult(),
  walking_speed(1.0)
{
  node_mult = 1 / path->nodes[0].time;
  next_node_nr = path->nodes.size() > 1 ? 1 : 0;
}

PathWalker::~PathWalker

(

)

[virtual]

Definition at line 36 of file path_walker.cpp.

{
}

PathWalker::PathWalker

(

const PathWalker &

)

[private]

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Member Function Documentation

Vector PathWalker::advance

(

float

elapsed_time

)

[virtual]

advances the path walker on the path and returns its new position

Definition at line 41 of file path_walker.cpp.

References advance_node(), current_node_nr, get_pos(), goback_node(), next_node_nr, node_mult, node_time, Path::nodes, path, running, Path::Node::time, and walking_speed.

{
  if (!running) return path->nodes[current_node_nr].position;

  assert(elapsed_time >= 0);

  elapsed_time *= fabsf(walking_speed);

  const Path::Node* current_node = & (path->nodes[current_node_nr]);
  while(node_time + elapsed_time * node_mult >= 1) {
    elapsed_time -= (1 - node_time) / node_mult;

    if(walking_speed > 0) {
      advance_node();
    } else if(walking_speed < 0) {
      goback_node();
    }

    current_node = & (path->nodes[current_node_nr]);
    node_time = 0;
    if(walking_speed > 0) {
      node_mult = 1 / current_node->time;
    } else {
      node_mult = 1 / path->nodes[next_node_nr].time;
    }
  }

  node_time += elapsed_time * node_mult;

  return get_pos();
}

Vector PathWalker::get_pos

(

)

current position of path walker

Definition at line 74 of file path_walker.cpp.

References current_node_nr, next_node_nr, node_time, Path::nodes, path, and Path::Node::position.

Referenced by advance().

{
  const Path::Node* current_node = & (path->nodes[current_node_nr]);
  const Path::Node* next_node = & (path->nodes[next_node_nr]);
  Vector new_pos = current_node->position +
    (next_node->position - current_node->position) * node_time;

  return new_pos;
}

void PathWalker::goto_node

(

int

node_no

)

advance until at given node, then stop

Definition at line 85 of file path_walker.cpp.

References running, and stop_at_node_nr.

{
  if (node_no == stop_at_node_nr) return;
  running = true;
  stop_at_node_nr = node_no;
}

void PathWalker::start_moving

(

)

start advancing automatically

Definition at line 93 of file path_walker.cpp.

References running, and stop_at_node_nr.

{
  running = true;
  stop_at_node_nr = -1;
}

void PathWalker::stop_moving

(

)

stop advancing automatically

Definition at line 100 of file path_walker.cpp.

References next_node_nr, and stop_at_node_nr.

{
  stop_at_node_nr = next_node_nr;
}

bool PathWalker::is_moving

(

)

[inline]

returns true if PathWalker is currently moving

Definition at line 51 of file path_walker.hpp.

References running.

                   {
    return running;
  }

void PathWalker::advance_node

(

)

[private]

Definition at line 106 of file path_walker.cpp.

References Path::CIRCULAR, current_node_nr, Path::mode, next_node_nr, Path::nodes, Path::ONE_SHOT, path, Path::PING_PONG, running, stop_at_node_nr, and walking_speed.

Referenced by advance().

{
  current_node_nr = next_node_nr;
  if (static_cast<int>(current_node_nr) == stop_at_node_nr) running = false;

  if(next_node_nr + 1 < path->nodes.size()) {
    next_node_nr++;
    return;
  }

  switch(path->mode) {
    case Path::ONE_SHOT:
      next_node_nr = path->nodes.size() - 1;
      walking_speed = 0;
      return;

    case Path::PING_PONG:
      walking_speed = -walking_speed;
      next_node_nr = path->nodes.size() > 1 ? path->nodes.size() - 2 : 0;
      return;

    case Path::CIRCULAR:
      next_node_nr = 0;
      return;
  }

  // we shouldn't get here
  assert(false);
  next_node_nr = path->nodes.size() - 1;
  walking_speed = 0;
}

void PathWalker::goback_node

(

)

[private]

Definition at line 139 of file path_walker.cpp.

References current_node_nr, Path::mode, next_node_nr, Path::nodes, path, Path::PING_PONG, and walking_speed.

Referenced by advance().

{
  current_node_nr = next_node_nr;

  if(next_node_nr > 0) {
    next_node_nr--;
    return;
  }

  switch(path->mode) {
    case Path::PING_PONG:
      walking_speed = -walking_speed;
      next_node_nr = path->nodes.size() > 1 ? 1 : 0;
      return;
    default:
      break;
  }

  assert(false);
  next_node_nr = 0;
  walking_speed = 0;
}

PathWalker& PathWalker::operator=

(

const PathWalker &

)

[private]

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Member Data Documentation

const Path* PathWalker::path

Definition at line 55 of file path_walker.hpp.

Referenced by advance(), advance_node(), get_pos(), goback_node(), and PathWalker().

bool PathWalker::running [private]

set to false to immediately stop advancing

Definition at line 64 of file path_walker.hpp.

Referenced by advance(), advance_node(), goto_node(), is_moving(), and start_moving().

size_t PathWalker::current_node_nr [private]

Definition at line 66 of file path_walker.hpp.

Referenced by advance(), advance_node(), get_pos(), and goback_node().

size_t PathWalker::next_node_nr [private]

Definition at line 67 of file path_walker.hpp.

Referenced by advance(), advance_node(), get_pos(), goback_node(), PathWalker(), and stop_moving().

int PathWalker::stop_at_node_nr [private]

stop advancing automatically when this node is reached

Definition at line 72 of file path_walker.hpp.

Referenced by advance_node(), goto_node(), start_moving(), and stop_moving().

float PathWalker::node_time [private]

the position between the current node and the next node as fraction between 0 and 1

Definition at line 78 of file path_walker.hpp.

Referenced by advance(), and get_pos().

float PathWalker::node_mult [private]

Definition at line 79 of file path_walker.hpp.

Referenced by advance(), and PathWalker().

float PathWalker::walking_speed [private]

Definition at line 81 of file path_walker.hpp.

Referenced by advance(), advance_node(), and goback_node().

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The documentation for this class was generated from the following files:

• src/object/path_walker.hpp
• src/object/path_walker.cpp

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