[example] Add boxes example

(cherry picked from commit ad4ea97e6d8ae72a3bcd84053caef9005efa686f)

examples/CMakeLists.txt

@@ -11,6 +11,7 @@ add_subdirectory(atlas_puppet)
 add_subdirectory(atlas_simbicon)
 add_subdirectory(biped_stand)
 add_subdirectory(box_stacking)
+add_subdirectory(boxes)
 add_subdirectory(drag_and_drop)
 add_subdirectory(empty)
 add_subdirectory(heightmap)

examples/boxes/CMakeLists.txt

@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 3.22.1)
+
+get_filename_component(example_name ${CMAKE_CURRENT_LIST_DIR} NAME)
+
+project(${example_name})
+
+set(required_components utils-urdf gui-osg)
+set(required_libraries dart dart-utils-urdf dart-gui-osg)
+
+if(DART_IN_SOURCE_BUILD)
+  dart_build_example_in_source(${example_name} LINK_LIBRARIES ${required_libraries})
+  return()
+endif()
+
+find_package(DART 6.14.0 REQUIRED COMPONENTS ${required_components} CONFIG)
+
+file(GLOB srcs "*.cpp" "*.hpp")
+add_executable(${example_name} ${srcs})
+target_link_libraries(${example_name} PUBLIC ${required_libraries})

examples/boxes/README.md

@@ -0,0 +1,20 @@
+This project is dependent on DART. Please make sure a proper version of DART is 
+installed before building this project.
+
+## Build Instructions
+
+From this directory:
+
+    $ mkdir build
+    $ cd build
+    $ cmake ..
+    $ make
+
+## Execute Instructions
+
+Launch the executable from the build directory above:
+
+    $ ./{generated_executable}
+
+Follow the instructions detailed in the console.
+

examples/boxes/main.cpp

@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2011-2024, The DART development contributors
+ * All rights reserved.
+ *
+ * The list of contributors can be found at:
+ *   https://github.com/dartsim/dart/blob/main/LICENSE
+ *
+ * This file is provided under the following "BSD-style" License:
+ *   Redistribution and use in source and binary forms, with or
+ *   without modification, are permitted provided that the following
+ *   conditions are met:
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *   CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *   DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ *   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ *   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ *   AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ *   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ *   ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *   POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <dart/gui/osg/osg.hpp>
+
+#include <dart/dart.hpp>
+
+#include <osgShadow/ShadowMap>
+
+using namespace dart;
+
+[[nodiscard]] dynamics::SkeletonPtr createBox(
+    const Eigen::Vector3d& position,
+    const Eigen::Vector3d& size = Eigen::Vector3d(1, 1, 1),
+    const Eigen::Vector3d& color
+    = dart::math::Random::uniform<Eigen::Vector3d>(0.0, 1.0))
+{
+  static size_t index = 0;
+  dynamics::SkeletonPtr boxSkel
+      = dynamics::Skeleton::create("box" + std::to_string(index++));
+
+  // Give the floor a body
+  dynamics::BodyNodePtr boxBody
+      = boxSkel->createJointAndBodyNodePair<dynamics::FreeJoint>(nullptr)
+            .second;
+
+  // Give the body a shape
+  auto boxShape = std::make_shared<dynamics::BoxShape>(size);
+  dynamics::ShapeNode* shapeNode = boxBody->createShapeNodeWith<
+      dynamics::VisualAspect,
+      dynamics::CollisionAspect,
+      dynamics::DynamicsAspect>(boxShape);
+  shapeNode->getVisualAspect()->setColor(color);
+
+  // Put the body into position
+  Eigen::Isometry3d tf = Eigen::Isometry3d::Identity();
+  tf.translation() = position;
+  boxBody->getParentJoint()->setTransformFromParentBodyNode(tf);
+
+  return boxSkel;
+}
+
+int main()
+{
+  // Create an empty world
+  auto world = simulation::World::create();
+
+  // Create dim x dim x dim boxes
+  auto dim = 5;
+  for (auto i = 0; i < dim; ++i) {
+    for (auto j = 0; j < dim; ++j) {
+      for (auto k = 0; k < dim; ++k) {
+        auto x = i - dim / 2;
+        auto y = j - dim / 2;
+        auto z = k + 1;
+        auto position = Eigen::Vector3d(x, y, z);
+        auto size = Eigen::Vector3d(0.9, 0.9, 0.9);
+        auto color = Eigen::Vector3d(
+            static_cast<double>(i) / dim,
+            static_cast<double>(j) / dim,
+            static_cast<double>(k) / dim);
+        auto box = createBox(position, size, color);
+        world->addSkeleton(box);
+      }
+    }
+  }
+
+  // Create ground
+  auto ground = dynamics::Skeleton::create("ground");
+  auto groundBody
+      = ground->createJointAndBodyNodePair<dynamics::WeldJoint>().second;
+  auto groundShapeNode = groundBody->createShapeNodeWith<
+      dynamics::VisualAspect,
+      dynamics::CollisionAspect,
+      dynamics::DynamicsAspect>(
+      std::make_shared<dynamics::BoxShape>(Eigen::Vector3d(25.0, 25.0, 0.1)));
+  groundShapeNode->getVisualAspect()->setColor(dart::Color::LightGray());
+  world->addSkeleton(ground);
+
+  // Wrap a WorldNode around it
+  ::osg::ref_ptr<gui::osg::RealTimeWorldNode> node
+      = new gui::osg::RealTimeWorldNode(world);
+
+  // Create a Viewer and set it up with the WorldNode
+  auto viewer = gui::osg::Viewer();
+  viewer.addWorldNode(node);
+
+  // Enable shadow
+  auto shadow
+      = dart::gui::osg::WorldNode::createDefaultShadowTechnique(&viewer);
+  if (auto sm = dynamic_cast<::osgShadow::ShadowMap*>(shadow.get())) {
+    auto mapResolution = static_cast<short>(std::pow(2, 12));
+    sm->setTextureSize(::osg::Vec2s(mapResolution, mapResolution));
+  }
+  node->setShadowTechnique(shadow);
+
+  viewer.addInstructionText(
+      "[Experimental] Please note: This example is in an experimental phase "
+      "and may not be fully functional at this time.\n");
+  viewer.addInstructionText("Press space to start free falling the box.\n");
+  std::cout << viewer.getInstructions() << std::endl;
+
+  // Set up the window to be 1360x768 (HD)
+  viewer.setUpViewInWindow(0, 0, 1360, 768);
+
+  // Adjust the viewpoint of the Viewer
+  viewer.getCameraManipulator()->setHomePosition(
+      ::osg::Vec3(15.0f, 15.0f, 10.0f),
+      ::osg::Vec3(0.00f, 0.00f, 2.50f),
+      ::osg::Vec3(0, 0, 1.0f));
+
+  // We need to re-dirty the CameraManipulator by passing it into the viewer
+  // again, so that the viewer knows to update its HomePosition setting
+  viewer.setCameraManipulator(viewer.getCameraManipulator());
+
+  // Begin running the application loop
+  viewer.run();
+
+  return 0;
+}