Box2D: b2PolygonShape Class Reference

Box2D 2.3.0 A 2D Physics Engine for Games

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b2PolygonShape Class Reference

`#include <b2PolygonShape.h>`

Inheritance diagram for b2PolygonShape:

## Public Member Functions
b2Shape * | Clone (b2BlockAllocator *allocator) const
| Implement b2Shape.
int32 | GetChildCount () const
void | Set (const b2Vec2 *points, int32 count)
void | SetAsBox (float32 hx, float32 hy)
void | SetAsBox (float32 hx, float32 hy, const b2Vec2 &center, float32 angle)
bool | TestPoint (const b2Transform &transform, const b2Vec2 &p) const
bool | RayCast (b2RayCastOutput *output, const b2RayCastInput &input, const b2Transform &transform, int32 childIndex) const
| Implement b2Shape.
void | ComputeAABB (b2AABB *aabb, const b2Transform &transform, int32 childIndex) const
void | ComputeMass (b2MassData *massData, float32 density) const
int32 | GetVertexCount () const
| Get the vertex count.
const b2Vec2 & | GetVertex (int32 index) const
| Get a vertex by index.
bool | Validate () const
Public Member Functions inherited from b2Shape
Type | GetType () const

## Public Attributes
b2Vec2 | m_centroid
b2Vec2 | m_vertices [b2_maxPolygonVertices]
b2Vec2 | m_normals [b2_maxPolygonVertices]
int32 | m_count
Public Attributes inherited from b2Shape
Type | m_type
float32 | m_radius

## Additional Inherited Members
Public Types inherited from b2Shape
enum | Type { e_circle = 0, e_edge = 1, e_polygon = 2, e_chain = 3, e_typeCount = 4 }

## Detailed Description

A convex polygon. It is assumed that the interior of the polygon is to the left of each edge. Polygons have a maximum number of vertices equal to b2_maxPolygonVertices. In most cases you should not need many vertices for a convex polygon.

## Member Function Documentation

void b2PolygonShape::ComputeAABB | ( | b2AABB * | aabb,
|  | const b2Transform & | transform,
|  | int32 | childIndex
| ) |  | const
| virtual

See Also
  b2Shape::ComputeAABB

Implements b2Shape.

void b2PolygonShape::ComputeMass | ( | b2MassData * | massData,
|  | float32 | density
| ) |  | const
| virtual

See Also
  b2Shape::ComputeMass

Implements b2Shape.

int32 b2PolygonShape::GetChildCount | ( |  | ) | const
| virtual

See Also
  b2Shape::GetChildCount

Implements b2Shape.

void b2PolygonShape::Set | ( | const b2Vec2 * | points,
|  | int32 | count
| ) |  |

Create a convex hull from the given array of local points. The count must be in the range [3, b2_maxPolygonVertices].

Warning
  the points may be re-ordered, even if they form a convex polygon
  collinear points are handled but not removed. Collinear points may lead to poor stacking behavior.

void b2PolygonShape::SetAsBox | ( | float32 | hx,
|  | float32 | hy
| ) |  |

Build vertices to represent an axis-aligned box centered on the local origin.

Parameters

  hx | the half-width.
  hy | the half-height.

void b2PolygonShape::SetAsBox | ( | float32 | hx,
|  | float32 | hy,
|  | const b2Vec2 & | center,
|  | float32 | angle
| ) |  |

Build vertices to represent an oriented box.

Parameters

  hx | the half-width.
  hy | the half-height.
  center | the center of the box in local coordinates.
  angle | the rotation of the box in local coordinates.

bool b2PolygonShape::TestPoint | ( | const b2Transform & | transform,
|  | const b2Vec2 & | p
| ) |  | const
| virtual

See Also
  b2Shape::TestPoint

Implements b2Shape.

bool b2PolygonShape::Validate | ( |  | ) | const

Validate convexity. This is a very time consuming operation.

Returns
  true if valid

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

- b2PolygonShape.h
- b2PolygonShape.cpp