playrho::d2::DistanceProxy Class Reference

Distance Proxy. More...

#include <playrho/d2/DistanceProxy.hpp>

Public Types
using	ConstNormalIterator = ConstNormalPointer
	Constant normal iterator.
using	ConstNormalPointer = const UnitVec *
	Constant normal pointer.
using	ConstVertexIterator = ConstVertexPointer
	Constant vertex iterator.
using	ConstVertexPointer = const Length2 *
	Constant vertex pointer.

Public Member Functions
	DistanceProxy ()=default
	Default constructor.
	DistanceProxy (const DistanceProxy &copy) noexcept
	Copy constructor. More...
	DistanceProxy (const NonNegative< Length > &vertexRadius, const VertexCounter count, const Length2 *vertices, const UnitVec *normals) noexcept
	Initializing constructor. More...
auto	GetNormal (VertexCounter index) const noexcept
	Gets the normal for the given index. More...
Span< const UnitVec >	GetNormals () const noexcept
	Gets the normals.
auto	GetVertex (VertexCounter index) const noexcept
	Gets a vertex by index. More...
auto	GetVertexCount () const noexcept
	Gets the vertex count. More...
auto	GetVertexRadius () const noexcept
	Gets the vertex radius of the vertices of the associated shape. More...
Span< const Length2 >	GetVertices () const noexcept
	Gets the vertices.

Related Functions
(Note that these are not member functions.)
AABB	ComputeAABB (const DistanceProxy &proxy, const Transformation &xf) noexcept
	Computes the AABB. More...
AABB	ComputeAABB (const DistanceProxy &proxy, const Transformation &xfm0, const Transformation &xfm1) noexcept
	Computes the AABB. More...
DistanceOutput	Distance (const DistanceProxy &proxyA, const Transformation &transformA, const DistanceProxy &proxyB, const Transformation &transformB, DistanceConf conf=DistanceConf{})
	Determines the closest points between two shapes using an iterative method. More...
SeparationInfo	GetMaxSeparation (const DistanceProxy &proxy1, const DistanceProxy &proxy2, Length stop=MaxFloat *Meter)
	Gets the max separation information. More...
SeparationInfo	GetMaxSeparation (const DistanceProxy &proxy1, const Transformation &xf1, const DistanceProxy &proxy2, const Transformation &xf2)
	Gets the max separation information. More...
SeparationInfo	GetMaxSeparation (const DistanceProxy &proxy1, const Transformation &xf1, const DistanceProxy &proxy2, const Transformation &xf2, Length stop)
	Gets the max separation information. More...
SeparationInfo	GetMaxSeparation4x4 (const DistanceProxy &proxy1, const Transformation &xf1, const DistanceProxy &proxy2, const Transformation &xf2)
	Gets the max separation information for the first four vertices of the two given shapes. More...
template<class T >
VertexCounter	GetSupportIndex (const DistanceProxy &proxy, T dir) noexcept
	Gets the supporting vertex index in given direction for given distance proxy. More...
auto	GetVertexRadius (const DistanceProxy &arg) noexcept
	Gets the vertex radius property of a given distance proxy.
bool	operator!= (const DistanceProxy &lhs, const DistanceProxy &rhs) noexcept
	Determines with the two given distance proxies are not equal.
bool	operator== (const DistanceProxy &lhs, const DistanceProxy &rhs) noexcept
	Determines with the two given distance proxies are equal.
RayCastOutput	RayCast (const DistanceProxy &proxy, const RayCastInput &input, const Transformation &transform) noexcept
	Cast a ray against the distance proxy. More...
Area	TestOverlap (const DistanceProxy &proxyA, const Transformation &xfA, const DistanceProxy &proxyB, const Transformation &xfB, DistanceConf conf=DistanceConf{})
	Determine if two generic shapes overlap. More...
bool	TestPoint (const DistanceProxy &proxy, const Length2 &point) noexcept
	Tests a point for containment in the given distance proxy. More...

Detailed Description

Distance Proxy.

A distance proxy aggregates a convex set of vertices, their normals, and a vertex radius of those vertices. This can be visualized as a convex N-sided polygon with rounded corners. It's meant to represent any single portion of a shape identified by its child-index.

Warning

It is the programmer's responsibility to ensure that the DistanceProxy does not outlive the pointed-to vertices or normals!

Examples

Compositor.cpp.

Constructor & Destructor Documentation

DistanceProxy() [1/2]

playrho::d2::DistanceProxy::DistanceProxy ( const DistanceProxy &  copy )

inlinenoexcept

Copy constructor.

Warning

It is the programmer's responsibility to ensure that this DistanceProxy does not outlive the copied from DistanceProxy.

DistanceProxy() [2/2]

playrho::d2::DistanceProxy::DistanceProxy ( const NonNegative< Length > &  vertexRadius, const VertexCounter  count, const Length2 *  vertices, const UnitVec *  normals  )

inlinenoexcept

Initializing constructor.

Constructs a distance proxy for n-point shape (like a polygon).

Parameters

vertexRadius	Radius of the given vertices.
count	Count of elements of the vertices and normals arrays.
vertices	Pointer to array of vertices of shape (relative to shape's origin).
normals	Pointer to array of normals of the shape.

Note

The vertices collection must have more than zero elements and no more than MaxShapeVertices elements.

Warning

It is the programmer's responsibility to ensure that the DistanceProxy does not outlive the pointed-to vertices or normals!

Behavior not specified if vertices array has less than one element or more than MaxShapeVertices elements.

Behavior is not specified if vertices are not in counter-clockwise order.

Behavior is not specified if shape defined by the vertices is not convex.

Behavior is not specified if normals aren't normals for adjacent vertices.

Behavior is not specified if any normal is not unique.

Member Function Documentation

GetNormal()

auto playrho::d2::DistanceProxy::GetNormal ( VertexCounter  index ) const

inlinenoexcept

Gets the normal for the given index.

Precondition

The given index is less than GetVertexCount().

Referenced by playrho::d2::GetManifold(), GetMaxSeparation(), and GetMaxSeparation4x4().

GetVertex()

auto playrho::d2::DistanceProxy::GetVertex ( VertexCounter  index ) const

inlinenoexcept

Gets a vertex by index.

Parameters

index

Index value less than count of vertices represented by this proxy.

Precondition

The given index is less than GetVertexCount().

Returns

Vertex linear position (relative to shape's origin) at the given index.

See also

Distance, GetVertexCount.

Referenced by playrho::d2::Manifold::CollideShapes(), playrho::d2::GetManifold(), GetMaxSeparation(), GetMaxSeparation4x4(), and playrho::d2::GetSeparationScenario().

GetVertexCount()

auto playrho::d2::DistanceProxy::GetVertexCount ( ) const

inlinenoexcept

Gets the vertex count.

This is the count of valid vertex elements that this object provides.

Returns

Value between 0 and MaxShapeVertices.

Note

This only returns 0 if this proxy was default constructed.

Referenced by playrho::d2::Manifold::CollideShapes(), Distance(), playrho::d2::GetManifold(), GetMaxSeparation(), playrho::d2::GetSeparationScenario(), and playrho::d2::Shape::GetVertexCount().

GetVertexRadius()

auto playrho::d2::DistanceProxy::GetVertexRadius ( ) const

inlinenoexcept

Gets the vertex radius of the vertices of the associated shape.

Returns

Non-negative distance.

Referenced by playrho::d2::Manifold::CollideShapes(), playrho::d2::GetManifold(), and TestOverlap().

Friends And Related Function Documentation

ComputeAABB() [1/2]

AABB ComputeAABB ( const DistanceProxy &  proxy, const Transformation &  xf  )

related

Computes the AABB.

Computes the Axis Aligned Bounding Box (AABB) for the given child shape at a given a transform.

Parameters

proxy	Distance proxy for the child shape.
xf	World transform of the shape.

Precondition

xf is valid.

Returns

AABB for the proxy shape or the default AABB if the proxy has a zero vertex count.

ComputeAABB() [2/2]

AABB ComputeAABB ( const DistanceProxy &  proxy, const Transformation &  xfm0, const Transformation &  xfm1  )

related

Computes the AABB.

Computes the Axis Aligned Bounding Box (AABB) for the given child shape at the given transforms.

Parameters

proxy	Distance proxy for the child shape.
xfm0	World transform 0 of the shape.
xfm1	World transform 1 of the shape.

Precondition

xfm0 and xfm1 are both valid.

Returns

AABB for the proxy shape or the default AABB if the proxy has a zero vertex count.

Distance()

DistanceOutput Distance ( const DistanceProxy &  proxyA, const Transformation &  transformA, const DistanceProxy &  proxyB, const Transformation &  transformB, DistanceConf  conf = DistanceConf{}  )

related

Determines the closest points between two shapes using an iterative method.

Note

Supports any combination of convex shapes.

Uses the G.J.K. (GJK) algorithm: "a method for determining the minimum distance between two convex sets".

On the first call, size(conf.cache.indices) should be zero.

Parameters

proxyA	Proxy A.
transformA	Transform of A.
proxyB	Proxy B.
transformB	Transform of B.
conf	Configuration to use including the simplex cache for assisting the determination.

Returns

Closest points between the two shapes, the count of iterations it took to determine them, and the reason iterations stopped. The iteration count will always be greater than zero unless DefaultMaxDistanceIters is zero.

See also

https://en.wikipedia.org/wiki/Gilbert%2DJohnson%2DKeerthi_distance_algorithm

GetMaxSeparation.

GetMaxSeparation() [1/3]

SeparationInfo GetMaxSeparation ( const DistanceProxy &  proxy1, const DistanceProxy &  proxy2, Length  stop = MaxFloat *Meter  )

related

Gets the max separation information.

Returns

Index of the vertex and normal from proxy1, index of the vertex from proxy2 (that had the maximum separation distance from each other in the direction of that normal), and the maximal distance.

See also

Distance.

GetMaxSeparation() [2/3]

SeparationInfo GetMaxSeparation ( const DistanceProxy &  proxy1, const Transformation &  xf1, const DistanceProxy &  proxy2, const Transformation &  xf2  )

related

Gets the max separation information.

Note

Prefer using this function - over the GetMaxSeparation function that takes a stopping length - when it's already known that the two convex shapes' AABBs overlap.

Returns

Index of the vertex and normal from proxy1, index of the vertex from proxy2 (that had the maximum separation distance from each other in the direction of that normal), and the maximal distance.

See also

Distance.

Referenced by playrho::d2::Manifold::CollideShapes().

GetMaxSeparation() [3/3]

SeparationInfo GetMaxSeparation ( const DistanceProxy &  proxy1, const Transformation &  xf1, const DistanceProxy &  proxy2, const Transformation &  xf2, Length  stop  )

related

Gets the max separation information.

Returns

Index of the vertex and normal from proxy1, index of the vertex from proxy2 (that had the maximum separation distance from each other in the direction of that normal), and the maximal distance.

See also

Distance.

GetMaxSeparation4x4()

SeparationInfo GetMaxSeparation4x4 ( const DistanceProxy &  proxy1, const Transformation &  xf1, const DistanceProxy &  proxy2, const Transformation &  xf2  )

related

Gets the max separation information for the first four vertices of the two given shapes.

This is a version of the get-max-separation functions that is optimized for two quadrilateral (4-sided) polygons.

Returns

Index of the vertex and normal from proxy1, index of the vertex from proxy2 (that had the maximum separation distance from each other in the direction of that normal), and the maximal distance.

See also

Distance.

Referenced by playrho::d2::Manifold::CollideShapes().

GetSupportIndex()

template<class T >

VertexCounter GetSupportIndex ( const DistanceProxy &  proxy, T  dir  )

related

Gets the supporting vertex index in given direction for given distance proxy.

This finds the vertex that's most significantly in direction of the given vector and returns its index.

Note

0 is returned for a given zero length direction vector.

Parameters

proxy	Distance proxy object to find index in if a valid index exists for it.
dir	Direction vector to find index for.

Returns

InvalidVertex if d is invalid or the count of vertices is zero, otherwise a value from 0 to one less than count.

See also

GetVertexCount().

TestOverlap()

Area TestOverlap ( const DistanceProxy &  proxyA, const Transformation &  xfA, const DistanceProxy &  proxyB, const Transformation &  xfB, DistanceConf  conf = DistanceConf{}  )

related

Determine if two generic shapes overlap.

Note

The returned touching state information typically agrees with that returned from the CollideShapes function. This is not always the case however especially when the separation or overlap distance is closer to zero.

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

• Library/include/playrho/d2/DistanceProxy.hpp
• Library/include/playrho/d2/AABB.hpp
• Library/include/playrho/d2/Distance.hpp
• Library/include/playrho/d2/RayCastOutput.hpp
• Library/include/playrho/d2/ShapeSeparation.hpp