net.stemkoski.bagel

Class PlatformPhysics

java.lang.Object

net.stemkoski.bagel.Physics

net.stemkoski.bagel.PlatformPhysics

public class PlatformPhysics
extends Physics

Extension of the Physics class, useful in games with a side-view perspective and platform games in particular. In this context, Physics.accelerationValue, Physics.maximumSpeed, and Physics.decelerationValue refer to horizontal movement; this class includes additional variables to quantify jump strength, the force of gravity (which constantly accelerates an object downwards), and terminal velocity (maximum vertical speed).

Field Summary

Fields

Modifier and Type	Field and Description
double	gravity constant downwards acceleration
double	jumpSpeed initial vertical velocity when jumping
double	terminalVelocity maximum vertical speed

Fields inherited from class net.stemkoski.bagel.Physics

accelerationValue, accelerationVector, decelerationValue, maximumSpeed, positionVector, velocityVector

Constructor Summary

Constructors

Constructor and Description
PlatformPhysics(double accValue, double maxHorizontalSpeed, double decValue, double jumpSpeed, double gravity, double terminalVelocity) Initialize values used by physics simulation.

Method Summary

Modifier and Type	Method and Description
void	jump() Simulate jumping, using value stored in jumpSpeed.
void	update(double dt) Update the position of this object according to velocity, acceleration, and gravity.

Methods inherited from class net.stemkoski.bagel.Physics

accelerateAtAngle, bounceAgainst, getMotionAngle, getSpeed, setMotionAngle, setSpeed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

jumpSpeed

public double jumpSpeed

initial vertical velocity when jumping

gravity

public double gravity

constant downwards acceleration

terminalVelocity

public double terminalVelocity

maximum vertical speed

Constructor Detail

PlatformPhysics

public PlatformPhysics(double accValue,
                       double maxHorizontalSpeed,
                       double decValue,
                       double jumpSpeed,
                       double gravity,
                       double terminalVelocity)

Initialize values used by physics simulation.

Parameters:

accValue - walk/run acceleration value

maxHorizontalSpeed - maximum horizontal speed

decValue - walk/run deceleration value

jumpSpeed - initial vertical velocity when jumping

gravity - force of gravity; constant downwards acceleration

terminalVelocity - maximum vertical speed

Method Detail

jump

public void jump()

Simulate jumping, using value stored in jumpSpeed.

update

public void update(double dt)

Update the position of this object according to velocity, acceleration, and gravity. Deceleration is applied if no acceleration (other than gravity) is present. Horizontal speed is bounded by Physics.maximumSpeed and vertical speed is bounded by terminalVelocity.

Overrides:

update in class Physics

Parameters:

dt - elapsed time (seconds) since previous iteration of game loop (typically approximately 1/60 second)