ShapeReifier Class Reference

Detailed Description

The interface for converting shape descriptions to real shapes.

Any entity that consumes shape descriptions must implement this interface.

This class explicitly enumerates all concrete shapes in its methods. The addition of a new concrete shape class requires the addition of a new corresponding method. There should never be an ImplementGeometry method that accepts the Shape base class as an argument; it should only operate on concrete derived classes.

The expected workflow is for a class that needs to turn shape specifications into concrete geometry instances to implement the ShapeReifier interface and invoke the Shape::Reify() method. For example, a simple reifier that requires no user data would look like:

class SimpleReifier : public ShapeReifier {
  void ProcessShape(const Shape& shape) {
    // Requires no user data.
    shape.Reify(this);
  }
  ...
  void ImplementGeometry(const Sphere& sphere, void*) override {
    // Do work to create a sphere.
  }
};

Or a complex reifier that requires user data would look like:

class ComplexReifier : public ShapeReifier {
  void ProcessShape(const Shape& shape) {
    ImportantData data{...};
    shape.Reify(this, &data);
  }
  ...
  void ImplementGeometry(const Sphere& sphere, void* data) override {
    DRAKE_ASSERT(data != nullptr);
    ImportantData& data = *static_cast<ImportantData*>(data);
    // Do work to create a sphere using the provided user data.
  }
};

Implementing a particular shape may require more data than is strictly encapsulated in the Shape. The Implement* interface supports passing user data through a type-erased void*. Because a single class invoked Shape::Reify() it is in a position to provide exactly the data the shape implementations require.

#include <drake/geometry/shape_specification.h>

Public Member Functions
virtual	~ShapeReifier ()
virtual void	ImplementGeometry (const Box &box, void *user_data)
virtual void	ImplementGeometry (const Capsule &capsule, void *user_data)
virtual void	ImplementGeometry (const Convex &convex, void *user_data)
virtual void	ImplementGeometry (const Cylinder &cylinder, void *user_data)
virtual void	ImplementGeometry (const Ellipsoid &ellipsoid, void *user_data)
virtual void	ImplementGeometry (const HalfSpace &half_space, void *user_data)
virtual void	ImplementGeometry (const Mesh &mesh, void *user_data)
virtual void	ImplementGeometry (const MeshcatCone &cone, void *user_data)
virtual void	ImplementGeometry (const Sphere &sphere, void *user_data)

Protected Member Functions
	ShapeReifier ()=default
virtual void	DefaultImplementGeometry (const Shape &shape)
	The default implementation of ImplementGeometry(): it throws an exception using ThrowUnsupportedGeometry(). More...
virtual void	ThrowUnsupportedGeometry (const std::string &shape_name)
	Derived ShapeReifiers can replace the default message for unsupported geometries by overriding this method. More...
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	ShapeReifier (const ShapeReifier &)=default
ShapeReifier &	operator= (const ShapeReifier &)=default
	ShapeReifier (ShapeReifier &&)=default
ShapeReifier &	operator= (ShapeReifier &&)=default

Constructor & Destructor Documentation

~ShapeReifier()

virtual ~ShapeReifier ( )

virtual

ShapeReifier() [1/3]

ShapeReifier ( const ShapeReifier &  )

protecteddefault

ShapeReifier() [2/3]

ShapeReifier ( ShapeReifier &&  )

protecteddefault

ShapeReifier() [3/3]

ShapeReifier ( )

protecteddefault

Member Function Documentation

DefaultImplementGeometry()

virtual void DefaultImplementGeometry ( const Shape &  shape )

protectedvirtual

The default implementation of ImplementGeometry(): it throws an exception using ThrowUnsupportedGeometry().

The purpose of this function is to facilitate reifiers that would call the same API on all shapes (e.g., call an API with a Shape& parameter). This reduces the implementation boilerplate.

ImplementGeometry() [1/9]

virtual void ImplementGeometry ( const Box &  box, void *  user_data  )

virtual

ImplementGeometry() [2/9]

virtual void ImplementGeometry ( const Capsule &  capsule, void *  user_data  )

virtual

ImplementGeometry() [3/9]

virtual void ImplementGeometry ( const Convex &  convex, void *  user_data  )

virtual

ImplementGeometry() [4/9]

virtual void ImplementGeometry ( const Cylinder &  cylinder, void *  user_data  )

virtual

ImplementGeometry() [5/9]

virtual void ImplementGeometry ( const Ellipsoid &  ellipsoid, void *  user_data  )

virtual

ImplementGeometry() [6/9]

virtual void ImplementGeometry ( const HalfSpace &  half_space, void *  user_data  )

virtual

ImplementGeometry() [7/9]

virtual void ImplementGeometry ( const Mesh &  mesh, void *  user_data  )

virtual

ImplementGeometry() [8/9]

virtual void ImplementGeometry ( const MeshcatCone &  cone, void *  user_data  )

virtual

ImplementGeometry() [9/9]

virtual void ImplementGeometry ( const Sphere &  sphere, void *  user_data  )

virtual

operator=() [1/2]

ShapeReifier& operator= ( const ShapeReifier &  )

protecteddefault

operator=() [2/2]

ShapeReifier& operator= ( ShapeReifier &&  )

protecteddefault

ThrowUnsupportedGeometry()

virtual void ThrowUnsupportedGeometry ( const std::string &  shape_name )

protectedvirtual

Derived ShapeReifiers can replace the default message for unsupported geometries by overriding this method.

The name of the unsupported shape type is given as the single parameter.

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

• drake/geometry/shape_specification.h