MaxSpeed Class Reference

Classes
class	SpeedDecrease
	An internal class to store and handle speed decrease related data. More...
class	SpeedIncrease
	An internal class to store and handle speed increase related data. More...

Public Types
enum	{   MS_INCREASE_MIN , MS_INCREASE_ZIPPER = MS_INCREASE_MIN , MS_INCREASE_SLIPSTREAM , MS_INCREASE_NITRO ,   MS_INCREASE_RUBBER , MS_INCREASE_SKIDDING , MS_INCREASE_RED_SKIDDING , MS_INCREASE_MAX }
	The categories to use for increasing the speed of a kart: Increase due to zipper, slipstream, nitro, rubber band, skidding usage.
enum	{   MS_DECREASE_MIN , MS_DECREASE_TERRAIN = MS_DECREASE_MIN , MS_DECREASE_AI , MS_DECREASE_BUBBLE ,   MS_DECREASE_SQUASH , MS_DECREASE_MAX }
	The categories to use for decreasing the speed of a kart: Decrease due to terrain, different AI levels and end controller.

Public Member Functions
	MaxSpeed (AbstractKart *kart)
	This class handles maximum speed for karts. More...
void	increaseMaxSpeed (unsigned int category, float add_speed, float engine_force, int duration, int fade_out_time)
	Sets an increased maximum speed for a category. More...
void	instantSpeedIncrease (unsigned int category, float add_speed, float speed_boost, float engine_force, int duration, int fade_out_time)
	This adjusts the top speed using increaseMaxSpeed, but additionally causes an instant speed boost, which can be smaller than add-max-speed. More...
void	setSlowdown (unsigned int category, float max_speed_fraction, int fade_in_time, int duration=-1)
	Defines a slowdown, which is in fraction of top speed. More...
int	getSpeedIncreaseTicksLeft (unsigned int category)
	Returns how much increased speed time is left over in the given category. More...
int	isSpeedIncreaseActive (unsigned int category)
	Returns if increased speed is active in the given category. More...
int	isSpeedDecreaseActive (unsigned int category)
	Returns if decreased speed is active in the given category. More...
void	update (int ticks)
	Updates all speed increase and decrease objects, and determines the current maximum speed. More...
void	reset ()
	Reset to prepare for a restart. More...
void	saveState (BareNetworkString *buffer) const
	Saves the speed data in a network string for rewind. More...
void	rewindTo (BareNetworkString *buffer)
	Restore a saved state. More...
void	setMinSpeed (float s)
	Sets the minimum speed a kart should have. More...
float	getCurrentMaxSpeed () const
	Returns the current maximum speed for this kart.
float	getCurrentAdditionalEngineForce () const
	Returns the additional engine force.

Private Attributes
AbstractKart *	m_kart
	A pointer to the kart to which this speed handling object belongs.
float	m_current_max_speed
	The current maximum speed.
float	m_add_engine_force
	Additional engine force, summed from all SpeedIncrease engine forces.
float	m_min_speed
	If >0 then the minimum speed a kart should have (used for zippers).
SpeedDecrease	m_speed_decrease [MS_DECREASE_MAX]
	Stores all speed decrease related information for each possible category.
SpeedIncrease	m_speed_increase [MS_INCREASE_MAX]
	Stores all speed increase related information for each possible category.

Friends
class	KartRewinder

Constructor & Destructor Documentation

MaxSpeed()

MaxSpeed::MaxSpeed

(

AbstractKart *

kart

)

This class handles maximum speed for karts.

Several factors can influence the maximum speed a kart can drive, some will decrease the maximum speed, some will increase the maximum speed. Slowdowns are specified in fraction of the (kart specific) maximum speed of that kart. The following categories are defined:

• terrain-specific slow downs
• AI related slow down (low level AIs might drive slower than player)
• end controller related AI (end controller drives slower) The largest slowdown of all those factors is applied to the maximum speed of the kart. Increase of maximum speed is given absolute, i.e. in m/s. The following circumstances can increase the maximum speed:
• Use of a zipper
• Use of sliptstream
• Use of nitro The speed increases for all those are added after applying the maximum slowdown fraction. At the end the maximum is capped by a value specified in stk_config (to avoid issues with physics etc).

Member Function Documentation

getSpeedIncreaseTicksLeft()

int MaxSpeed::getSpeedIncreaseTicksLeft

(

unsigned int

category

)

Returns how much increased speed time is left over in the given category.

Parameters

category

Which category to report on.

increaseMaxSpeed()

void MaxSpeed::increaseMaxSpeed	(	unsigned int	category,
		float	add_speed,
		float	engine_force,
		int	duration,
		int	fade_out_time
	)

Sets an increased maximum speed for a category.

Parameters

category	The category for which to set the higher maximum speed.
add_speed	How much speed (in m/s) is added to the maximum speed.
duration	How long the speed increase will last.
fade_out_time	How long the maximum speed will fade out linearly.

instantSpeedIncrease()

void MaxSpeed::instantSpeedIncrease	(	unsigned int	category,
		float	add_max_speed,
		float	speed_boost,
		float	engine_force,
		int	duration,
		int	fade_out_time
	)

This adjusts the top speed using increaseMaxSpeed, but additionally causes an instant speed boost, which can be smaller than add-max-speed.

(e.g. a zipper can give an instant boost of 5 m/s, but over time would allow the speed to go up by 10 m/s). Note that bullet does not restrict speed (e.g. by simulating air resistance), so without capping the speed (which is done my this object) the speed would go arbitrary high over time

Parameters

category	The category for which the speed is increased.
add_max_speed	Increase of the maximum allowed speed.
speed_boost	An instant speed increase for this kart.
engine_force	Additional engine force.
duration	Duration of the increased speed.
fade_out_time	How long the maximum speed will fade out linearly.

isSpeedDecreaseActive()

int MaxSpeed::isSpeedDecreaseActive

(

unsigned int

category

)

Returns if decreased speed is active in the given category.

Parameters

category

Which category to report on.

isSpeedIncreaseActive()

int MaxSpeed::isSpeedIncreaseActive

(

unsigned int

category

)

Returns if increased speed is active in the given category.

Parameters

category

Which category to report on.

reset()

void MaxSpeed::reset

(

)

Reset to prepare for a restart.

It just overwrites each entry with a newly constructed values, i.e. values that don't cause any slowdown or speedup.

rewindTo()

void MaxSpeed::rewindTo

(

BareNetworkString *

buffer

)

Restore a saved state.

Parameters

buffer

Saved state.

saveState()

void MaxSpeed::saveState

(

BareNetworkString *

buffer

)

const

Saves the speed data in a network string for rewind.

Parameters

buffer

Pointer to the network string to store the data.

setMinSpeed()

void MaxSpeed::setMinSpeed ( float  s )

inline

Sets the minimum speed a kart should have.

This is used to guarantee that e.g. zippers on ramps will always fast enough for the karts to reach the other end. If set to a negative number, it will have no effect.

setSlowdown()

void MaxSpeed::setSlowdown	(	unsigned int	category,
		float	max_speed_fraction,
		int	fade_in_ticks,
		int	duration = -1
	)

Defines a slowdown, which is in fraction of top speed.

Parameters

category	The category for which the speed is increased.
max_speed_fraction	Fraction of top speed to allow only.
fade_in_time	How long till maximum speed is capped.
duration	How long the effect will lasts. The value of -1 (default) indicates that this effect stays active forever (i.e. till its value is changed to something else).

update()

void MaxSpeed::update

(

int

ticks

)

Updates all speed increase and decrease objects, and determines the current maximum speed.

Note that the function can be called with dt=0, in which case the maximum speed will be updated, but no change to any of the speed increase/decrease objects will be done.

Parameters

dt	Time step size (dt=0 only updates the current maximum speed).

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

• karts/max_speed.hpp
• karts/max_speed.cpp