#include <Shape.hpp>

Collaboration diagram for playrho::d2::Shape:

Classes
struct	Concept
	Internal configuration concept. More...

struct	Model
	Internal model configuration concept. More...

Public Member Functions
	Shape () noexcept=default
	Default constructor. More...

	Shape (const Shape &other)=default
	Copy constructor.

	Shape (Shape &&other) noexcept=default
	Move constructor.

template<typename T , typename Tp = DecayedTypeIfNotSelf<T>, typename = std::enable_if_t<std::is_copy_constructible<Tp>::value>>
	Shape (T &&arg)
	Initializing constructor. More...

Shape &	operator= (const Shape &other)=default
	Copy assignment operator.

Shape &	operator= (Shape &&other)=default
	Move assignment operator.

template<typename T , typename Tp = DecayedTypeIfNotSelf<T>, typename = std::enable_if_t<std::is_copy_constructible<Tp>::value>>
Shape &	operator= (T &&other)
	Move assignment operator. More...

void	swap (Shape &other) noexcept
	Swap support.

bool	has_value () const noexcept
	Checks whether this instance contains a value.

Private Types
template<typename Type , typename DecayedType = std::decay_t<Type>>
using	DecayedTypeIfNotSelf = std::enable_if_t<!std::is_same_v< DecayedType, Shape >, DecayedType >
	Decayed type if not same as this class. More...

Private Attributes
std::shared_ptr< const Concept >	m_self
	Self pointer.

Friends
ChildCounter	GetChildCount (const Shape &shape) noexcept
	Gets the number of child primitives of the shape. More...

DistanceProxy	GetChild (const Shape &shape, ChildCounter index)
	Gets the "child" for the given index. More...

MassData	GetMassData (const Shape &shape) noexcept
	Gets the mass properties of this shape using its dimensions and density. More...

NonNegative< Length >	GetVertexRadius (const Shape &shape, ChildCounter idx)
	Gets the vertex radius of the indexed child of the given shape. More...

Real	GetFriction (const Shape &shape) noexcept
	Gets the coefficient of friction. More...

Real	GetRestitution (const Shape &shape) noexcept
	Gets the coefficient of restitution value of the given shape.

NonNegative< AreaDensity >	GetDensity (const Shape &shape) noexcept
	Gets the density of the given shape. More...

void	Transform (Shape &shape, const Mat22 &m)
	Transforms all of the given shape's vertices by the given transformation matrix. More...

const void *	GetData (const Shape &shape) noexcept
	Gets a pointer to the underlying data. More...

TypeID	GetType (const Shape &shape) noexcept
	Gets the type info of the use of the given shape. More...

template<typename T >
std::add_pointer_t< std::add_const_t< T > >	TypeCast (const Shape *value) noexcept
	Converts the given shape into its current configuration value. More...

bool	operator== (const Shape &lhs, const Shape &rhs) noexcept
	Equality operator for shape to shape comparisons.

bool	operator!= (const Shape &lhs, const Shape &rhs) noexcept
	Inequality operator for shape to shape comparisons.

Related Functions
(Note that these are not member functions.)
AABB	ComputeAABB (const Shape &shape, const Transformation &xf) noexcept
	Computes the AABB for the given shape with the given transformation.

RayCastOutput	RayCast (const Shape &shape, ChildCounter childIndex, const RayCastInput &input, const Transformation &transform) noexcept
	Cast a ray against the child of the given shape. More...

bool	TestPoint (const Shape &shape, Length2 point) noexcept
	Test a point for containment in the given shape. More...

template<typename T >
T	TypeCast (const Shape &value)
	Casts the specified instance into the template specified type. More...

Detailed Description

Shape.

A shape is used for collision detection. You can create a shape from any supporting type. Shapes are conceptually made up of zero or more convex child shapes where each child shape is made up of zero or more vertices and an associated radius called its "vertex radius".

Note

This class's design provides a "polymorphic value type" offering polymorphism without public inheritance. This is based on a technique that's described by Sean Parent in his January 2017 Norwegian Developers Conference London talk "Better Code: Runtime Polymorphism". With this implementation, different shapes types can be had by constructing instances of this class with the different types that provide the required support. Different shapes of a given type meanwhile are had by providing different values for the type.

A shape can be constructor from or have its value set to any value whose type T has at least the following function definitions available for it:

bool operator==(const T& lhs, const T& rhs) noexcept;
ChildCounter GetChildCount(const T&) noexcept;
DistanceProxy GetChild(const T&, ChildCounter index);
MassData GetMassData(const T&) noexcept;
NonNegative<Length> GetVertexRadius(const T&, ChildCounter idx);
NonNegative<AreaDensity> GetDensity(const T&) noexcept;
Real GetFriction(const T&) noexcept;
Real GetRestitution(const T&) noexcept;
void Transform(T&, const Mat22& value);

See also: FixtureConf; https://youtu.be/QGcVXgEVMJg; https://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Polymorphic_Value_Types

Examples: DistanceJoint.cpp, FrictionJoint.cpp, GearJoint.cpp, HelloWorld.cpp, MotorJoint.cpp, PrismaticJoint.cpp, RevoluteJoint.cpp, RopeJoint.cpp, Shape.cpp, WeldJoint.cpp, WheelJoint.cpp, World.cpp, WorldBody.cpp, WorldContact.cpp, and WorldFixture.cpp.

Member Typedef Documentation

◆ DecayedTypeIfNotSelf

template<typename Type , typename DecayedType = std::decay_t<Type>>

using playrho::d2::Shape::DecayedTypeIfNotSelf = std::enable_if_t<!std::is_same_v<DecayedType, Shape>, DecayedType>

private

Decayed type if not same as this class.

Note: This is done separately from other checks to ensure order of compiler's SFINAE processing and to ensure elimination of self class before attempting to process other checks like is_copy_constructible. This prevents a compiler error that started showing up in gcc-9.

Constructor & Destructor Documentation

◆ Shape() [1/2]

playrho::d2::Shape::Shape ( )

defaultnoexcept

Default constructor.

Postcondition: has_value() returns false.

Referenced by operator=().

◆ Shape() [2/2]

template<typename T , typename Tp = DecayedTypeIfNotSelf<T>, typename = std::enable_if_t<std::is_copy_constructible<Tp>::value>>

playrho::d2::Shape::Shape ( T && arg )

inlineexplicit

Initializing constructor.

Parameters

arg	Configuration value to construct a shape instance for.

Note: See the class notes section for an explanation of requirements on a type T for its values to be valid candidates for this function.

Postcondition: has_value() returns true.

Exceptions

std::bad_alloc if there's a failure allocating storage.

Member Function Documentation

◆ operator=()

template<typename T , typename Tp = DecayedTypeIfNotSelf<T>, typename = std::enable_if_t<std::is_copy_constructible<Tp>::value>>

Shape& playrho::d2::Shape::operator= ( T && other )

inline

Move assignment operator.

Postcondition: has_value() returns true.

Friends And Related Function Documentation

◆ GetChild

DistanceProxy GetChild	(	const Shape &	shape,
		ChildCounter	index
	)

friend

Gets the "child" for the given index.

Parameters

shape	Shape to get "child" shape of.
index	Index to a child element of the shape. Value must be less than the number of child primitives of the shape.

Note: The shape must remain in scope while the proxy is in use.

Exceptions

InvalidArgument if the given index is out of range.

See also: GetChildCount

Referenced by playrho::d2::Shape::Model< T >::GetChild_().

◆ GetChildCount

ChildCounter GetChildCount ( const Shape & shape )

friend

Gets the number of child primitives of the shape.

Returns: Non-negative count.

Referenced by playrho::d2::Shape::Model< T >::GetChildCount_().

◆ GetData

const void* GetData ( const Shape & shape )

friend

Gets a pointer to the underlying data.

Note: Provided for introspective purposes like visitation.

◆ GetDensity

NonNegative<AreaDensity> GetDensity ( const Shape & shape )

friend

Gets the density of the given shape.

Returns: Non-negative density (in mass per area).

Referenced by playrho::d2::Shape::Model< T >::GetDensity_().

◆ GetFriction

Real GetFriction ( const Shape & shape )

friend

Gets the coefficient of friction.

Returns: Value of 0 or higher.

Referenced by playrho::d2::Shape::Model< T >::GetFriction_().

◆ GetMassData

MassData GetMassData ( const Shape & shape )

friend

Gets the mass properties of this shape using its dimensions and density.

Returns: Mass data for this shape.

Referenced by playrho::d2::Shape::Model< T >::GetMassData_().

◆ GetType

TypeID GetType ( const Shape & shape )

friend

Gets the type info of the use of the given shape.

Note: This is not the same as calling GetTypeID<Shape>().

Returns: Type info of the underlying value's type.

◆ GetVertexRadius

NonNegative<Length> GetVertexRadius	(	const Shape &	shape,
		ChildCounter	idx
	)

friend

Gets the vertex radius of the indexed child of the given shape.

This gets the radius from the vertex that the shape's "skin" should extend outward by. While any edges - line segments between multiple vertices - are straight, corners between them (the vertices) are rounded and treated as rounded. Shapes with larger vertex radiuses compared to edge lengths therefore will be more prone to rolling or having other shapes more prone to roll off of them. Here's an image of a shape configured via a PolygonShapeConf with it's skin drawn:

Parameters

shape	Shape to get child's vertex radius for.
idx	Child index to get vertex radius for.

Note: This must be a non-negative value.

See also: UseVertexRadius

Exceptions

InvalidArgument if the child index is not less than the child count.

Referenced by playrho::d2::Shape::Model< T >::GetVertexRadius_().

◆ Transform

void Transform	(	Shape &	shape,
		const Mat22 &	m
	)

friend

Transforms all of the given shape's vertices by the given transformation matrix.

See also: https://en.wikipedia.org/wiki/Transformation_matrix

Note: This may throw std::bad_alloc or any exception that's thrown by the constructor for the model's underlying data type.

Exceptions

std::bad_alloc if there's a failure allocating storage.

Referenced by playrho::d2::Shape::Model< T >::Transform_().

◆ TypeCast() [1/2]

template<typename T >

T TypeCast ( const Shape & value )

Exceptions

std::bad_cast If the template specified type is not the type of data underlying the given instance.

See also: GetType(const Shape&)

◆ TypeCast [2/2]

template<typename T >

std::add_pointer_t<std::add_const_t<T> > TypeCast ( const Shape * value )

friend

Converts the given shape into its current configuration value.

Note: The design for this was based off the design of the C++17 std::any class and its associated std::any_cast function. The code for this is based off of the std::any code from the LLVM Project.

See also: https://llvm.org/; GetType(const Shape&)

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

Shape.hpp
AABB.hpp
RayCastOutput.hpp

Classes

Public Member Functions

Private Types

Private Attributes

Friends

Related Functions

Detailed Description

Member Typedef Documentation

◆ DecayedTypeIfNotSelf

Constructor & Destructor Documentation

◆ Shape() [1/2]

◆ Shape() [2/2]

Member Function Documentation

◆ operator=()

Friends And Related Function Documentation

◆ GetChild

◆ GetChildCount

◆ GetData

◆ GetDensity

◆ GetFriction

◆ GetMassData

◆ GetType

◆ GetVertexRadius

◆ Transform

◆ TypeCast() [1/2]

◆ TypeCast [2/2]