Purge RigidBody* from examples/compass_gait (RobotLocomotion#12618)

Adds CompassGaitGeometry (which generalizes the previous visualization by supporting the parameterized geometry)
Removes CompassGait.urdf (and .xacro), but git remembers

bindings/pydrake/examples/compass_gait_py.cc

@@ -4,6 +4,7 @@
 #include "drake/bindings/pydrake/documentation_pybind.h"
 #include "drake/bindings/pydrake/pydrake_pybind.h"
 #include "drake/examples/compass_gait/compass_gait.h"
+#include "drake/examples/compass_gait/compass_gait_geometry.h"
 #include "drake/examples/compass_gait/gen/compass_gait_continuous_state.h"
 #include "drake/examples/compass_gait/gen/compass_gait_params.h"
 
@@ -28,7 +29,14 @@ PYBIND11_MODULE(compass_gait, m) {
 
   py::class_<CompassGait<T>, LeafSystem<T>>(
       m, "CompassGait", doc.CompassGait.doc)
-      .def(py::init<>(), doc.CompassGait.ctor.doc);
+      .def(py::init<>(), doc.CompassGait.ctor.doc)
+      .def("get_minimal_state_output_port",
+          &CompassGait<T>::get_minimal_state_output_port, py_reference_internal,
+          doc.CompassGait.get_minimal_state_output_port.doc)
+      .def("get_floating_base_state_output_port",
+          &CompassGait<T>::get_floating_base_state_output_port,
+          py_reference_internal,
+          doc.CompassGait.get_floating_base_state_output_port.doc);
 
   // TODO(russt): Remove custom bindings once #8096 is resolved.
   py::class_<CompassGaitParams<T>, BasicVector<T>>(
@@ -79,6 +87,31 @@ PYBIND11_MODULE(compass_gait, m) {
           doc.CompassGaitContinuousState.set_stancedot.doc)
       .def("set_swingdot", &CompassGaitContinuousState<T>::set_swingdot,
           doc.CompassGaitContinuousState.set_swingdot.doc);
+
+  py::class_<CompassGaitGeometry, LeafSystem<double>>(
+      m, "CompassGaitGeometry", doc.CompassGaitGeometry.doc)
+      .def_static("AddToBuilder",
+          py::overload_cast<systems::DiagramBuilder<double>*,
+              const systems::OutputPort<double>&,
+              const CompassGaitParams<double>&, geometry::SceneGraph<double>*>(
+              &CompassGaitGeometry::AddToBuilder),
+          py::arg("builder"), py::arg("floating_base_state_port"),
+          py::arg("compass_gait_params"), py::arg("scene_graph"),
+          // Keep alive, ownership: `return` keeps `builder` alive.
+          py::keep_alive<0, 1>(),
+          // See #11531 for why `py_reference` is needed.
+          py_reference, doc.CompassGaitGeometry.AddToBuilder.doc_4args)
+      .def_static("AddToBuilder",
+          py::overload_cast<systems::DiagramBuilder<double>*,
+              const systems::OutputPort<double>&,
+              geometry::SceneGraph<double>*>(
+              &CompassGaitGeometry::AddToBuilder),
+          py::arg("builder"), py::arg("floating_base_state_port"),
+          py::arg("scene_graph"),
+          // Keep alive, ownership: `return` keeps `builder` alive.
+          py::keep_alive<0, 1>(),
+          // See #11531 for why `py_reference` is needed.
+          py_reference, doc.CompassGaitGeometry.AddToBuilder.doc_3args);
 }
 
 }  // namespace pydrake

bindings/pydrake/examples/test/compass_gait_test.py

@@ -1,14 +1,21 @@
 import unittest
 
 from pydrake.examples.compass_gait import (
-    CompassGaitParams, CompassGait, CompassGaitContinuousState
-    )
-from pydrake.systems.analysis import (
-    Simulator
-    )
+    CompassGait, CompassGaitContinuousState,
+    CompassGaitGeometry, CompassGaitParams
+)
+from pydrake.geometry import SceneGraph
+from pydrake.systems.analysis import Simulator
+from pydrake.systems.framework import DiagramBuilder
 
 
 class TestCompassGait(unittest.TestCase):
+    def test_compass_gait(self):
+        plant = CompassGait()
+        # Confirm the spelling on the output ports.
+        plant.get_minimal_state_output_port()
+        plant.get_floating_base_state_output_port()
+
     def test_params(self):
         params = CompassGaitParams()
         params.set_mass_hip(1.)
@@ -35,6 +42,30 @@ def test_state(self):
         self.assertEqual(state.stancedot(), 3.)
         self.assertEqual(state.swingdot(), 4.)
 
+    def test_geometry(self):
+        builder = DiagramBuilder()
+        plant = builder.AddSystem(CompassGait())
+        scene_graph = builder.AddSystem(SceneGraph())
+        geom = CompassGaitGeometry.AddToBuilder(
+            builder=builder,
+            floating_base_state_port=plant.get_floating_base_state_output_port(),  # noqa
+            scene_graph=scene_graph)
+        # Confirming that the resulting diagram builds.
+        builder.Build()
+        self.assertIsInstance(geom, CompassGaitGeometry)
+
+    def test_geometry_with_params(self):
+        builder = DiagramBuilder()
+        plant = builder.AddSystem(CompassGait())
+        scene_graph = builder.AddSystem(SceneGraph())
+        geom = CompassGaitGeometry.AddToBuilder(
+            builder=builder,
+            floating_base_state_port=plant.get_floating_base_state_output_port(),  # noqa
+            compass_gait_params=CompassGaitParams(), scene_graph=scene_graph)
+        # Confirming that the resulting diagram builds.
+        builder.Build()
+        self.assertIsInstance(geom, CompassGaitGeometry)
+
     def test_simulation(self):
         # Basic compass_gait simulation.
         compass_gait = CompassGait()

bindings/pydrake/examples/test/rimless_wheel_test.py

@@ -42,8 +42,7 @@ def test_geometry(self):
         scene_graph = builder.AddSystem(SceneGraph())
         geom = RimlessWheelGeometry.AddToBuilder(
             builder=builder,
-            floating_base_state_port=plant
-            .get_floating_base_state_output_port(),
+            floating_base_state_port=plant.get_floating_base_state_output_port(),  # noqa
             scene_graph=scene_graph)
         # Confirming that the resulting diagram builds.
         builder.Build()
@@ -55,8 +54,7 @@ def test_geometry_with_params(self):
         scene_graph = builder.AddSystem(SceneGraph())
         geom = RimlessWheelGeometry.AddToBuilder(
             builder=builder,
-            floating_base_state_port=plant
-            .get_floating_base_state_output_port(),
+            floating_base_state_port=plant.get_floating_base_state_output_port(),  # noqa
             rimless_wheel_params=RimlessWheelParams(), scene_graph=scene_graph)
         # Confirming that the resulting diagram builds.
         builder.Build()

examples/compass_gait/BUILD.bazel

@@ -39,20 +39,30 @@ drake_cc_library(
     ],
 )
 
+drake_cc_library(
+    name = "compass_gait_geometry",
+    srcs = ["compass_gait_geometry.cc"],
+    hdrs = ["compass_gait_geometry.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":compass_gait",
+        "//geometry:geometry_roles",
+        "//geometry:scene_graph",
+        "//math:geometric_transform",
+        "//systems/framework:diagram_builder",
+        "//systems/framework:leaf_system",
+    ],
+)
+
 drake_cc_binary(
     name = "simulate",
     srcs = ["simulate.cc"],
     add_test_rule = 1,
-    data = ["CompassGait.urdf"],
     test_rule_args = ["--target_realtime_rate=0.0"],
     deps = [
         ":compass_gait",
-        "//attic/multibody:rigid_body_tree",
-        "//attic/multibody/parsers",
-        "//attic/multibody/rigid_body_plant:drake_visualizer",
-        "//common:find_resource",
-        "//lcm",
-        "//math:geometric_transform",
+        ":compass_gait_geometry",
+        "//geometry:geometry_visualization",
         "//systems/analysis:simulator",
         "//systems/framework:diagram_builder",
         "@gflags",
@@ -61,7 +71,6 @@ drake_cc_binary(
 
 drake_cc_googletest(
     name = "compass_gait_test",
-    data = ["CompassGait.urdf"],
     deps = [
         ":compass_gait",
         "//common/test_utilities:eigen_matrix_compare",
@@ -70,6 +79,14 @@ drake_cc_googletest(
     ],
 )
 
+drake_cc_googletest(
+    name = "compass_gait_geometry_test",
+    deps = [
+        ":compass_gait",
+        ":compass_gait_geometry",
+    ],
+)
+
 install_data()
 
 add_lint_tests()