Chain shapes allow you to create a polygonal chain that is resistant to ghost collisions. More...

Data Structures
struct	b2ChainDef
	Used to create a chain of line segments. More...

Functions
b2ChainId	b2CreateChain (b2BodyId bodyId, const b2ChainDef *def)
	Create a chain shape.
void	b2DestroyChain (b2ChainId chainId)
	Destroy a chain shape.
b2WorldId	b2Chain_GetWorld (b2ChainId chainId)
	Get the world that owns this chain shape.
int	b2Chain_GetSegmentCount (b2ChainId chainId)
	Get the number of segments on this chain.
int	b2Chain_GetSegments (b2ChainId chainId, b2ShapeId *segmentArray, int capacity)
	Fill a user array with chain segment shape ids up to the specified capacity.
void	b2Chain_SetAllSurfaceMaterials (b2ChainId chainId, const b2SurfaceMaterial *material)
	Set the chain material on all segments.
void	b2Chain_SetSurfaceMaterial (b2ChainId chainId, const b2SurfaceMaterial *material, int segmentIndex)
	Set a chain material by segment index.
b2SurfaceMaterial	b2Chain_GetSurfaceMaterial (b2ChainId chainId, int segmentIndex)
	Get a chain material by segment index.
bool	b2Chain_IsValid (b2ChainId id)
	Chain identifier validation. Provides validation for up to 64K allocations.
b2ChainDef	b2DefaultChainDef (void)
	Use this to initialize your chain definition.

Detailed Description

Chain shapes allow you to create a polygonal chain that is resistant to ghost collisions.

Data Structure Documentation

struct b2ChainDef

Used to create a chain of line segments.

This is designed to eliminate ghost collisions with some limitations.

chains are one-sided
chains have no mass and should be used on static bodies
chains have a counter-clockwise winding order (normal points right of segment direction)
chains are either a loop or open
the distance between any two points must be greater than B2_LINEAR_SLOP
a chain shape should not self intersect (this is not validated)
an open chain shape needs a leading and trailing ghost point.
you may overlap two open chains using the ghost points to get smooth collision.
a chain shape creates multiple line segment shapes on the body https://en.wikipedia.org/wiki/Polygonal_chain Must be initialized using b2DefaultChainDef().
Warning
Do not use chain shapes unless you understand the limitations. This is an advanced feature.

Data Fields
bool	enableSensorEvents	Enable sensors to detect this chain. False by default.
b2Filter	filter	Contact filtering data.
b2Vec2	ghost1	Leading ghost point for an open chain. Distance from first point must be greater than B2_LINEAR_SLOP. Ignored for loops.
b2Vec2	ghost2	Ending ghost point for an open chain. Distance from last point must be greater than B2_LINEAR_SLOP. Ignored for loops.
int	internalValue	Used internally to detect a valid definition. DO NOT SET.
bool	isLoop	Indicates a closed chain formed by connecting the first and last point.
int	materialCount	The material count. Must be 1 or the segment count.
const b2SurfaceMaterial *	materials	One material for the whole chain or one for each segment. Cloned.
int	pointCount	The point count. At least 2 for an open chain and at least 3 for a loop. segmentCount = isLoop ? pointCount : pointCount - 1
const b2Vec2 *	points	Array of chain points. Each consecutive pair forms a segment. For a loop the last and first point form a segment. Cloned.
void *	userData	Use this to store application specific shape data.

Fill a user array with chain segment shape ids up to the specified capacity.

Returns the actual number of segments returned.

b2ChainId b2CreateChain	(	b2BodyId	bodyId,
		const b2ChainDef *	def )

Create a chain shape.