geometry_instance.h

#pragma once

#include <memory>
#include <optional>
#include <string>
#include <utility>

#include "drake/common/copyable_unique_ptr.h"
#include "drake/common/drake_copyable.h"
#include "drake/common/eigen_types.h"
#include "drake/geometry/geometry_ids.h"
#include "drake/geometry/geometry_roles.h"
#include "drake/geometry/shape_specification.h"
#include "drake/math/rigid_transform.h"

namespace drake {
namespace geometry {

/** A geometry instance combines a geometry definition (i.e., a shape of some
 sort), a pose (relative to a parent "frame" P), material information, and an
 opaque collection of metadata. The parent frame can be a registered frame or
 another registered geometry.

 Every %GeometryInstance must be named. The naming convention mirrors that of
 valid names in SDF files. Specifically, any user-specified name will have
 all leading and trailing space and tab characters trimmed off. The trimmed name
 will have to satisfy the following requirements:

   - cannot be empty, and
   - the name should be unique in the scope of its frame and role. For example,
     two GeometryInstances can both be called "ball" as long as they are
     affixed to different frames or if one is a collision geometry and the
     other is an illustration geometry. This is enforced when a role is assigned
     to the geometry.
     <!-- TODO(SeanCurtis-TRI): Update this when the perception role is also
     added.  -->

 If valid, the trimmed name will be assigned to the instance.

 Names *can* have internal whitespace (e.g., "my geometry name").

 @anchor canonicalized_geometry_names
 <h3>Canonicalized names</h3>

 The silent transformation of a user-defined name to canonical name mirrors that
 of specifying geometry names in an SDF file. Consider the following SDF
 snippet:

 @code{xml}
   ...
   <visual name="  visual">
     <geometry>
       <sphere>
         <radius>1.0</radius>
       </sphere>
     </geometry>
   </visual>
   ...
 @endcode

 The name has two leading whitespace characters. The parsing process will
 consider this name as equivalent to "visual" and tests for uniqueness and
 non-emptiness will be applied to that trimmed result. The following code has
 an analogous effect:

 ```
 scene_graph->RegisterGeometry(
    source_id, frame_id,
    make_unique<GeometryInstance>(pose, make_unique<Sphere>(1.0), "  visual"));
 ```

 The specified name includes leading whitespace. That name will be trimmed and
 the *result* will be stored in the %GeometryInstance (to be later validated by
 SceneGraph as part of geometry registration). Querying the instance of its name
 will return this *canonicalized* name.

 <!-- Note to developers: The sdf requirements for naming are captured in a
 unit test in `scene_graph_parser_detail_test.cc. See test
 VisualGeometryNameRequirements and keep those tests and this list in sync. -->
 */
class GeometryInstance {
 public:
  DRAKE_DEFAULT_COPY_AND_MOVE_AND_ASSIGN(GeometryInstance)

  /** Constructs a geometry instance specification.
   @param X_PG   The pose of this geometry (`G`) in its parent's frame (`P`).
   @param shape  The underlying shape for this geometry instance.
   @param name   The name of the geometry (must satisfy the name requirements).
   @throws std::exception if the canonicalized version of `name` is empty.
   */
  GeometryInstance(const math::RigidTransform<double>& X_PG, const Shape& shape,
                   const std::string& name);

  /** (Advanced) Overload that transfers ownership of `shape` (for performance).
   @pre shape is non-null.
   @exclude_from_pydrake_mkdoc{Cannot transfer ownership.} */
  GeometryInstance(const math::RigidTransform<double>& X_PG,
                   std::unique_ptr<Shape> shape, const std::string& name);

  /** Returns the globally unique id for this geometry specification. Every
   instantiation of %GeometryInstance will contain a unique id value. The id
   value is preserved across copies. After successfully registering this
   %GeometryInstance, this id will serve as the identifier for the registered
   representation as well.  */
  GeometryId id() const { return id_; }

  /** Returns the instance geometry's pose in its parent frame.  */
  const math::RigidTransformd& pose() const { return X_PG_; }

  /** Sets the pose of this instance in its parent's frame.  */
  void set_pose(const math::RigidTransformd& X_PG) { X_PG_ = X_PG; }

  /** Returns the underlying shape specification for this geometry instance.
   @pre release_shape() has not been called nor has this been moved-from. */
  const Shape& shape() const {
    DRAKE_THROW_UNLESS(shape_ != nullptr);
    return *shape_;
  }

  /** (Advanced) Transfers ownership of this geometry instance's underlying
   shape specification to the caller.
   @pre release_shape() has not been called nor has this been moved-from. */
  std::unique_ptr<Shape> release_shape() { return std::move(shape_); }

  /** Returns the *canonicalized* name for the instance.
   @sa @ref canonicalized_geometry_names "Canonicalized names"  */
  const std::string& name() const { return name_; }

  /** Sets the *canonicalized* name for the instance.
   @sa @ref canonicalized_geometry_names "Canonicalized names"  */
  void set_name(const std::string& name);

  /** Sets the proximity properties for the given instance.  */
  void set_proximity_properties(ProximityProperties properties) {
    proximity_properties_ = std::move(properties);
  }

  /** Sets the illustration properties for the given instance.  */
  void set_illustration_properties(IllustrationProperties properties) {
    illustration_properties_ = std::move(properties);
  }

  /** Sets the perception properties for the given instance.  */
  void set_perception_properties(PerceptionProperties properties) {
    perception_properties_ = std::move(properties);
  }

  /** Returns a pointer to the geometry's mutable proximity properties (if they
   are defined). Nullptr otherwise.  */
  ProximityProperties* mutable_proximity_properties() {
    if (proximity_properties_) return &*proximity_properties_;
    return nullptr;
  }

  /** Returns a pointer to the geometry's const proximity properties (if they
   are defined). Nullptr otherwise.  */
  const ProximityProperties* proximity_properties() const {
    if (proximity_properties_) return &*proximity_properties_;
    return nullptr;
  }

  /** Returns a pointer to the geometry's mutable illustration properties (if
   they are defined). Nullptr otherwise.  */
  IllustrationProperties* mutable_illustration_properties() {
    if (illustration_properties_) return &*illustration_properties_;
    return nullptr;
  }

  /** Returns a pointer to the geometry's const illustration properties (if
   they are defined). Nullptr otherwise.  */
  const IllustrationProperties* illustration_properties() const {
    if (illustration_properties_) return &*illustration_properties_;
    return nullptr;
  }

  /** Returns a pointer to the geometry's mutable perception properties (if
   they are defined). Nullptr otherwise.  */
  PerceptionProperties* mutable_perception_properties() {
    if (perception_properties_) return &*perception_properties_;
    return nullptr;
  }

  /** Returns a pointer to the geometry's const perception properties (if
   they are defined). Nullptr otherwise.  */
  const PerceptionProperties* perception_properties() const {
    if (perception_properties_) return &*perception_properties_;
    return nullptr;
  }

 private:
  // The *globally* unique identifier for this instance. It is functionally
  // const (i.e. defined in construction) but not marked const to allow for
  // default copying/assigning.
  GeometryId id_{};

  // The pose of the geometry relative to the parent frame it hangs on.
  math::RigidTransform<double> X_PG_;

  // The shape associated with this instance.
  copyable_unique_ptr<Shape> shape_;

  // The name of the geometry instance.
  std::string name_;

  // Optional properties.
  std::optional<ProximityProperties> proximity_properties_{};
  std::optional<IllustrationProperties> illustration_properties_{};
  std::optional<PerceptionProperties> perception_properties_{};
};

}  // namespace geometry
}  // namespace drake