BicyclePlatform Class Reference

Used to construct a pair of bicycle platforms: If one is pushed down, the other one rises. More...

#include <bicycle_platform.hpp>

Inherits MovingSprite.

List of all members.

Public Member Functions
	BicyclePlatform (const Reader &reader)
	BicyclePlatform (BicyclePlatform *master)
virtual	~BicyclePlatform ()
virtual HitResponse	collision (GameObject &other, const CollisionHit &hit)
	this function is called when the object collided with any other object
virtual void	update (float elapsed_time)
	This function is called once per frame and allows the object to update it's state.
Protected Attributes
BicyclePlatform *	master
	pointer to BicyclePlatform that does movement calculation
BicyclePlatform *	slave
	pointer to BicyclePlatform that reacts to master platform's movement calculation
Vector	center
	pivot point
float	radius
	radius of circle
float	angle
	current angle
float	angular_speed
	angular speed in rad per second
std::set< GameObject * >	contacts
	objects that are currently pushing on the platform
float	momentum
Private Member Functions
	BicyclePlatform (const BicyclePlatform &)
	angular momentum in rad per second per second
BicyclePlatform &	operator= (const BicyclePlatform &)

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Detailed Description

Used to construct a pair of bicycle platforms: If one is pushed down, the other one rises.

Definition at line 25 of file bicycle_platform.hpp.

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Constructor & Destructor Documentation

BicyclePlatform::BicyclePlatform

(

const Reader &

reader

)

Definition at line 26 of file bicycle_platform.cpp.

References center, and MovingObject::get_pos().

Referenced by update().

                                                     :
  MovingSprite(reader, LAYER_OBJECTS, COLGROUP_STATIC), 
  master(0),
  slave(0), 
  center(),
  radius(128), 
  angle(0), 
  angular_speed(0), 
  contacts(),
  momentum(0)
{
  center = get_pos();
}

BicyclePlatform::BicyclePlatform

(

BicyclePlatform *

master

)

Definition at line 40 of file bicycle_platform.cpp.

References MovingObject::get_bbox(), MovingObject::get_pos(), Rectf::get_width(), master, MovingObject::set_pos(), and slave.

                                                        :
  MovingSprite(*master), 
  master(master), 
  slave(this), 
  center(master->center), 
  radius(master->radius), 
  angle(master->angle + M_PI), 
  angular_speed(0), 
  contacts(),
  momentum(0)
{
  set_pos(get_pos() + Vector(master->get_bbox().get_width(), 0));
  master->master = master;
  master->slave = this;
}

BicyclePlatform::~BicyclePlatform

(

)

[virtual]

Definition at line 56 of file bicycle_platform.cpp.

References master, and slave.

{
  if ((this == master) && (master)) {
    slave->master = 0;
    slave->slave = 0;
  }
  if ((master) && (this == slave)) {
    master->master = 0;
    master->slave = 0;
  }
  master = 0;
  slave = 0;
}

BicyclePlatform::BicyclePlatform

(

const BicyclePlatform &

)

[private]

angular momentum in rad per second per second

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Member Function Documentation

HitResponse BicyclePlatform::collision	(	GameObject &	other,
		const CollisionHit &	hit
	)			[virtual]

this function is called when the object collided with any other object

Implements MovingObject.

Definition at line 71 of file bicycle_platform.cpp.

References contacts, FORCE_MOVE, MovingObject::get_bbox(), Player::get_grabbed_object(), Player::is_big(), momentum, Rectf::p2, and Vector::y.

{

  // somehow the hit parameter does not get filled in, so to determine (hit.top == true) we do this:
  MovingObject* mo = dynamic_cast<MovingObject*>(&other);
  if (!mo) return FORCE_MOVE;
  if ((mo->get_bbox().p2.y) > (get_bbox().p1.y + 2)) return FORCE_MOVE;

  Player* pl = dynamic_cast<Player*>(mo);
  if (pl) {
    if (pl->is_big()) momentum += 1;
    Portable* po = pl->get_grabbed_object();
    MovingObject* pomo = dynamic_cast<MovingObject*>(po);
    if (contacts.insert(pomo).second) momentum += 1;
  }

  if (contacts.insert(&other).second) momentum += 1;
  return FORCE_MOVE;
}

void BicyclePlatform::update

(

float

elapsed_time

)

[virtual]

This function is called once per frame and allows the object to update it's state.

The elapsed_time is the time since the last frame in seconds and should be the base for all timed calculations (don't use SDL_GetTicks directly as this will fail in pause mode)

Reimplemented from MovingSprite.

Definition at line 92 of file bicycle_platform.cpp.

References Sector::add_object(), angle, angular_speed, MovingObject::bbox, BicyclePlatform(), center, contacts, Sector::current(), MovingObject::dest, MovingObject::get_pos(), Rectf::get_size(), master, momentum, MovingObject::movement, radius, and slave.

{
  if (!slave) {
    Sector::current()->add_object(new BicyclePlatform(this));
    return;
  }
  if (!master) {
    return;
  }
  if (this == slave) {
    angle = master->angle + M_PI;
    while (angle < 0) { angle += 2*M_PI; } 
    while (angle > 2*M_PI) { angle -= 2*M_PI; } 
    Vector dest = center + Vector(cosf(angle), sinf(angle)) * radius - (bbox.get_size() * 0.5);
    movement = dest - get_pos();
  }
  if (this == master) {
    float momentum_diff = momentum - slave->momentum;
    contacts.clear(); momentum = 0;
    slave->contacts.clear(); slave->momentum = 0;

    float angular_momentum = cosf(angle) * momentum_diff;

    angular_speed += (angular_momentum * elapsed_time) * M_PI;
    angular_speed *= 1 - elapsed_time * 0.2;
    angle += angular_speed * elapsed_time;
    while (angle < 0) { angle += 2*M_PI; } 
    while (angle > 2*M_PI) { angle -= 2*M_PI; } 
    angular_speed = std::min(std::max(angular_speed, static_cast<float>(-128*M_PI*elapsed_time)), static_cast<float>(128*M_PI*elapsed_time));
    Vector dest = center + Vector(cosf(angle), sinf(angle)) * radius - (bbox.get_size() * 0.5);
    movement = dest - get_pos();

    center += Vector(angular_speed, 0) * elapsed_time * 32;
    slave->center += Vector(angular_speed, 0) * elapsed_time * 32;

  }
}

BicyclePlatform& BicyclePlatform::operator=

(

const BicyclePlatform &

)

[private]

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Member Data Documentation

BicyclePlatform* BicyclePlatform::master [protected]

pointer to BicyclePlatform that does movement calculation

Definition at line 36 of file bicycle_platform.hpp.

Referenced by BicyclePlatform(), update(), and ~BicyclePlatform().

BicyclePlatform* BicyclePlatform::slave [protected]

pointer to BicyclePlatform that reacts to master platform's movement calculation

Definition at line 37 of file bicycle_platform.hpp.

Referenced by BicyclePlatform(), update(), and ~BicyclePlatform().

Vector BicyclePlatform::center [protected]

pivot point

Definition at line 38 of file bicycle_platform.hpp.

Referenced by BicyclePlatform(), and update().

float BicyclePlatform::radius [protected]

radius of circle

Definition at line 39 of file bicycle_platform.hpp.

Referenced by update().

float BicyclePlatform::angle [protected]

current angle

Definition at line 40 of file bicycle_platform.hpp.

Referenced by update().

float BicyclePlatform::angular_speed [protected]

angular speed in rad per second

Definition at line 41 of file bicycle_platform.hpp.

Referenced by update().

std::set<GameObject*> BicyclePlatform::contacts [protected]

objects that are currently pushing on the platform

Definition at line 42 of file bicycle_platform.hpp.

Referenced by collision(), and update().

float BicyclePlatform::momentum [protected]

Definition at line 43 of file bicycle_platform.hpp.

Referenced by collision(), and update().

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

• src/object/bicycle_platform.hpp
• src/object/bicycle_platform.cpp

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