[wip] UrdfImporter: new plugin.

The main purpose is two-fold -- being able to visualize the URDF
hierarchy using standard tools, and as a showcase of the flexibility of
SceneData custom fields, which preserve everything including the
URDF-specific physics properties.

TODO: finish the data import (inertia matrices, etc.), make it more
  robust
TODO: mesh & material import -- delegating to AnySceneImporter for
  these, joining the nested hierarchies somehow (needs a utility in
  SceneTools, ideally)
TODO: ability to not import nested models but instead expose them as
  custom SceneData (string) fields -- needs ability to store strings
  there; what about the color overrides then? have a MeshMaterial field
  alone, without any mesh?
TODO: explicitly mark what's a joint and what's a link via a custom
  SceneData bit field, ideally -- needs bitfields in Corrade first
TODO: docs about custom fields
TODO: CI setup
TODO: tests, look for constraints in the URDF itself
TODO: expose in all packages
TODO: expose in FindMagnumPlugins

CMakeLists.txt

@@ -166,6 +166,7 @@ if(MAGNUM_BUILD_DEPRECATED)
     option(MAGNUM_WITH_TINYGLTFIMPORTER "Build TinyGltfImporter plugin" OFF)
 endif()
 option(MAGNUM_WITH_UFBXIMPORTER "Build UfbxImporter plugin" OFF)
+option(MAGNUM_WITH_URDFIMPORTER "Build UrdfImporter plugin" OFF)
 option(MAGNUM_WITH_WEBPIMPORTER "Build WebPImporter plugin" OFF)
 
 option(MAGNUM_BUILD_TESTS "Build unit tests" OFF)

src/MagnumPlugins/CMakeLists.txt

@@ -213,6 +213,10 @@ if(MAGNUM_WITH_UFBXIMPORTER)
     add_subdirectory(UfbxImporter)
 endif()
 
+if(MAGNUM_WITH_URDFIMPORTER)
+    add_subdirectory(UrdfImporter)
+endif()
+
 if(MAGNUM_WITH_WEBPIMPORTER)
     add_subdirectory(WebPImporter)
 endif()

src/MagnumPlugins/UrdfImporter/CMakeLists.txt

@@ -0,0 +1,68 @@
+#
+#   This file is part of Magnum.
+#
+#   Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
+#               2020, 2021, 2022 Vladimír Vondruš <[email protected]>
+#
+#   Permission is hereby granted, free of charge, to any person obtaining a
+#   copy of this software and associated documentation files (the "Software"),
+#   to deal in the Software without restriction, including without limitation
+#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
+#   and/or sell copies of the Software, and to permit persons to whom the
+#   Software is furnished to do so, subject to the following conditions:
+#
+#   The above copyright notice and this permission notice shall be included
+#   in all copies or substantial portions of the Software.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#   DEALINGS IN THE SOFTWARE.
+#
+
+find_package(Magnum REQUIRED Trade)
+find_package(pugixml CONFIG REQUIRED)
+
+if(MAGNUM_BUILD_PLUGINS_STATIC AND NOT DEFINED MAGNUM_URDFIMPORTER_BUILD_STATIC)
+    set(MAGNUM_URDFIMPORTER_BUILD_STATIC 1)
+endif()
+
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/configure.h.cmake
+               ${CMAKE_CURRENT_BINARY_DIR}/configure.h)
+
+# UrdfImporter plugin
+add_plugin(UrdfImporter
+    importers
+    "${MAGNUM_PLUGINS_IMPORTER_DEBUG_BINARY_INSTALL_DIR};${MAGNUM_PLUGINS_IMPORTER_DEBUG_LIBRARY_INSTALL_DIR}"
+    "${MAGNUM_PLUGINS_IMPORTER_RELEASE_BINARY_INSTALL_DIR};${MAGNUM_PLUGINS_IMPORTER_RELEASE_LIBRARY_INSTALL_DIR}"
+    UrdfImporter.conf
+    UrdfImporter.cpp
+    UrdfImporter.h)
+if(MAGNUM_URDFIMPORTER_BUILD_STATIC AND MAGNUM_BUILD_STATIC_PIC)
+    set_target_properties(UrdfImporter PROPERTIES POSITION_INDEPENDENT_CODE ON)
+endif()
+target_include_directories(UrdfImporter PUBLIC
+    ${PROJECT_SOURCE_DIR}/src
+    ${PROJECT_BINARY_DIR}/src)
+target_link_libraries(UrdfImporter PUBLIC
+    Magnum::Trade
+    pugixml::pugixml)
+
+install(FILES UrdfImporter.h ${CMAKE_CURRENT_BINARY_DIR}/configure.h
+    DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/UrdfImporter)
+
+# Automatic static plugin import
+if(MAGNUM_URDFIMPORTER_BUILD_STATIC)
+    install(FILES importStaticPlugin.cpp DESTINATION ${MAGNUM_PLUGINS_INCLUDE_INSTALL_DIR}/UrdfImporter)
+    target_sources(UrdfImporter INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/importStaticPlugin.cpp)
+endif()
+
+if(MAGNUM_BUILD_TESTS)
+    add_subdirectory(Test)
+endif()
+
+# MagnumPlugins UrdfImporter target alias for superprojects
+add_library(MagnumPlugins::UrdfImporter ALIAS UrdfImporter)

src/MagnumPlugins/UrdfImporter/Test/CMakeLists.txt

@@ -0,0 +1,65 @@
+#
+#   This file is part of Magnum.
+#
+#   Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
+#               2020, 2021, 2022 Vladimír Vondruš <[email protected]>
+#
+#   Permission is hereby granted, free of charge, to any person obtaining a
+#   copy of this software and associated documentation files (the "Software"),
+#   to deal in the Software without restriction, including without limitation
+#   the rights to use, copy, modify, merge, publish, distribute, sublicense,
+#   and/or sell copies of the Software, and to permit persons to whom the
+#   Software is furnished to do so, subject to the following conditions:
+#
+#   The above copyright notice and this permission notice shall be included
+#   in all copies or substantial portions of the Software.
+#
+#   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+#   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+#   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+#   DEALINGS IN THE SOFTWARE.
+#
+
+# IDE folder in VS, Xcode etc. CMake 3.12+, older versions have only the FOLDER
+# property that would have to be set on each target separately.
+set(CMAKE_FOLDER "MagnumPlugins/UrdfImporter/Test")
+
+if(CORRADE_TARGET_EMSCRIPTEN OR CORRADE_TARGET_ANDROID)
+    set(URDFIMPORTER_TEST_DIR ".")
+else()
+    set(URDFIMPORTER_TEST_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+endif()
+
+# CMake before 3.8 has broken $<TARGET_FILE*> expressions for iOS (see
+# https://gitlab.kitware.com/cmake/cmake/merge_requests/404) and since Corrade
+# doesn't support dynamic plugins on iOS, this sorta works around that. Should
+# be revisited when updating Travis to newer Xcode (xcode7.3 has CMake 3.6).
+if(NOT MAGNUM_URDFIMPORTER_BUILD_STATIC)
+    set(URDFIMPORTER_PLUGIN_FILENAME $<TARGET_FILE:UrdfImporter>)
+endif()
+
+# First replace ${} variables, then $<> generator expressions
+configure_file(${CMAKE_CURRENT_SOURCE_DIR}/configure.h.cmake
+               ${CMAKE_CURRENT_BINARY_DIR}/configure.h.in)
+file(GENERATE OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>/configure.h
+    INPUT ${CMAKE_CURRENT_BINARY_DIR}/configure.h.in)
+
+corrade_add_test(UrdfImporterTest UrdfImporterTest.cpp
+    LIBRARIES Magnum::Trade)
+target_include_directories(UrdfImporterTest PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>)
+if(MAGNUM_URDFIMPORTER_BUILD_STATIC)
+    target_link_libraries(UrdfImporterTest PRIVATE UrdfImporter)
+else()
+    # So the plugins get properly built when building the test
+    add_dependencies(UrdfImporterTest UrdfImporter)
+endif()
+if(CORRADE_BUILD_STATIC AND NOT MAGNUM_URDFIMPORTER_BUILD_STATIC)
+    # CMake < 3.4 does this implicitly, but 3.4+ not anymore (see CMP0065).
+    # That's generally okay, *except if* the build is static, the executable
+    # uses a plugin manager and needs to share globals with the plugins (such
+    # as output redirection and so on).
+    set_target_properties(UrdfImporterTest PROPERTIES ENABLE_EXPORTS ON)
+endif()

src/MagnumPlugins/UrdfImporter/Test/UrdfImporterTest.cpp

@@ -0,0 +1,104 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
+                2020, 2021, 2022 Vladimír Vondruš <[email protected]>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#include <Corrade/Containers/ArrayView.h>
+#include <Corrade/TestSuite/Tester.h>
+#include <Corrade/Utility/Algorithms.h>
+#include <Magnum/Trade/AbstractImporter.h>
+
+#include "configure.h"
+
+namespace Magnum { namespace Trade { namespace Test { namespace {
+
+struct UrdfImporterTest: TestSuite::Tester {
+    explicit UrdfImporterTest();
+
+    void openMemory();
+    void openTwice();
+    void importTwice();
+
+    /* Explicitly forbid system-wide plugin dependencies */
+    PluginManager::Manager<AbstractImporter> _manager{"nonexistent"};
+};
+
+/* Shared among all plugins that implement data copying optimizations */
+const struct {
+    const char* name;
+    bool(*open)(AbstractImporter&, Containers::ArrayView<const void>);
+} OpenMemoryData[]{
+    {"data", [](AbstractImporter& importer, Containers::ArrayView<const void> data) {
+        /* Copy to ensure the original memory isn't referenced */
+        Containers::Array<char> copy{NoInit, data.size()};
+        Utility::copy(Containers::arrayCast<const char>(data), copy);
+        return importer.openData(copy);
+    }},
+    {"memory", [](AbstractImporter& importer, Containers::ArrayView<const void> data) {
+        return importer.openMemory(data);
+    }},
+};
+
+UrdfImporterTest::UrdfImporterTest() {
+    addInstancedTests({&UrdfImporterTest::openMemory},
+        Containers::arraySize(OpenMemoryData));
+
+    addTests({&UrdfImporterTest::openTwice,
+              &UrdfImporterTest::importTwice});
+
+    /* Load the plugin directly from the build tree. Otherwise it's static and
+       already loaded. */
+    #ifdef URDFIMPORTER_PLUGIN_FILENAME
+    CORRADE_INTERNAL_ASSERT_OUTPUT(_manager.load(URDFIMPORTER_PLUGIN_FILENAME) & PluginManager::LoadState::Loaded);
+    #endif
+}
+
+void UrdfImporterTest::openMemory() {
+    /* Same as (a subset of) binary() except that it uses openData() &
+       openMemory() instead of openFile() to test data copying on import */
+
+    auto&& data = OpenMemoryData[testCaseInstanceId()];
+    setTestCaseDescription(data.name);
+
+    Containers::Pointer<AbstractImporter> importer = _manager.instantiate("UrdfImporter");
+    // TODO
+}
+
+void UrdfImporterTest::openTwice() {
+    Containers::Pointer<AbstractImporter> importer = _manager.instantiate("UrdfImporter");
+
+    // TODO
+
+    /* Shouldn't crash, leak or anything */
+}
+
+void UrdfImporterTest::importTwice() {
+    Containers::Pointer<AbstractImporter> importer = _manager.instantiate("UrdfImporter");
+
+    /* Verify that everything is working the same way on second use */
+    // TODO
+}
+
+}}}}
+
+CORRADE_TEST_MAIN(Magnum::Trade::Test::UrdfImporterTest)

src/MagnumPlugins/UrdfImporter/Test/configure.h.cmake

@@ -0,0 +1,27 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
+                2020, 2021, 2022 Vladimír Vondruš <[email protected]>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#cmakedefine URDFIMPORTER_PLUGIN_FILENAME "${URDFIMPORTER_PLUGIN_FILENAME}"
+#define URDFIMPORTER_TEST_DIR "${URDFIMPORTER_TEST_DIR}"