Portability | portable (needs FFI) |
---|---|

Stability | provisional |

Maintainer | felipe.lessa@gmail.com |

Functionality used by various modules and routines for initialization and change of global variables.

- initChipmunk :: IO ()
- type CpFloat = Float
- infinity :: CpFloat
- type Time = CpFloat
- type Angle = CpFloat
- resetShapeCounter :: IO ()
- getContactPersistence :: IO Int32
- setContactPersistence :: Int32 -> IO ()
- getCollisionSlop :: IO CpFloat
- setCollisionSlop :: CpFloat -> IO ()
- getBiasCoef :: IO CpFloat
- setBiasCoef :: CpFloat -> IO ()
- getJointBiasCoef :: IO CpFloat
- setJointBiasCoef :: CpFloat -> IO ()
- data Vector = Vector !CpFloat !CpFloat
- type Position = Vector
- fromAngle :: Angle -> Vector
- len :: Vector -> CpFloat
- normalize :: Vector -> Vector
- scale :: Vector -> CpFloat -> Vector
- toAngle :: Vector -> Angle
- dot :: Vector -> Vector -> CpFloat
- cross :: Vector -> Vector -> CpFloat
- perp :: Vector -> Vector
- project :: Vector -> Vector -> Vector
- rotate :: Vector -> Vector -> Vector
- unrotate :: Vector -> Vector -> Vector

# Initialization

Initilizes the Chipmunk library. This should be called once before using any functions of this library.

# Basic data types

Type synonym used to hint that the argument or result represents an angle in radians.

# Global variables

Chipmunk tries to maintein a very few number of global
variables to allow multiple `Physics.Hipmunk.Space.Space`

s
to be used simultaneously, however there are some.

## Shape counter

The shape counter is a global counter used for creating unique hash identifiers to the shapes.

resetShapeCounter :: IO ()Source

`resetShapeCounter`

reset the shape counter to its default value.
This is used to add determinism to a simulation. As the ids
created with this counter may affect the order in which the
collisions happen, there may be very slight differences in
different simulations.

However, be careful as you should not use shapes created
before a call to `resetCounter`

with shapes created after
it as they may have the same id.

## Contact persistence

This variable determines how long contacts should persist. It should be small as the cached contacts will only be close for a short time. (default is 3)

setContactPersistence :: Int32 -> IO ()Source

## Collision slop

The collision slop is the amount that shapes are allowed to penetrate. Setting this to zero will work just fine, but using a small positive amount will help prevent oscillating contacts. (default is 0.1)

setCollisionSlop :: CpFloat -> IO ()Source

## Bias coefficient

The amount of penetration to reduce in each step. Values should range from 0 to 1. Using large values will eliminate penetration in fewer steps, but can cause vibration. (default is 0.1)

setBiasCoef :: CpFloat -> IO ()Source

## Joint bias coefficient

Similar to the bias coefficient, but for all joints. In the future, joints might have their own bias coefficient instead. (default is 0.1)

setJointBiasCoef :: CpFloat -> IO ()Source

# Vectors

Type synonym used to hint that the argument or result represents a position.

fromAngle :: Angle -> VectorSource

Constructs an unitary vector pointing to the given angle (in radians).

toAngle :: Vector -> AngleSource

`toAngle v`

is the angle that `v`

has
with the vector `Vector 1 0`

(modulo `2*pi`

).

perp :: Vector -> VectorSource

`perp v`

is a vector of same length as `v`

but perpendicular
to `v`

(i.e. `toAngle (perp v) - toAngle v`

equals `pi/2`

modulo `2*pi`

).