USD pick with kind support, with test.

lib/mayaHydra/mayaPlugin/CMakeLists.txt

@@ -38,6 +38,7 @@ target_compile_definitions(${TARGET_NAME}
         $<$<BOOL:${IS_LINUX}>:LINUX>
         # Not sure if msvcc sets this automatically, but won't hurt to redefine
         $<$<BOOL:${IS_WINDOWS}>:_WIN32>
+        $<$<BOOL:${MayaUsd_FOUND}>:MAYAHYDRALIB_MAYAUSDAPI_ENABLED>
 )
 
 # -----------------------------------------------------------------------------
@@ -46,6 +47,7 @@ target_compile_definitions(${TARGET_NAME}
 target_include_directories(${TARGET_NAME} 
     PRIVATE
         $<$<BOOL:${UFE_FOUND}>:${UFE_INCLUDE_DIR}>
+        $<$<BOOL:${MayaUsd_FOUND}>:${MAYAUSD_INCLUDE_DIR}>
 )
 
 if(DEFINED MAYAUSD_VERSION)
@@ -73,6 +75,7 @@ target_link_libraries(${TARGET_NAME}
         ufeExtensions
         flowViewport
         $<$<BOOL:${UFE_FOUND}>:${UFE_LIBRARY}>
+        $<$<BOOL:${MayaUsd_FOUND}>:${MAYAUSDAPI_LIBRARY}>
 )
 
 # -----------------------------------------------------------------------------

lib/mayaHydra/mayaPlugin/renderOverride.cpp

@@ -82,8 +82,13 @@
 #include <pxr/imaging/hdx/tokens.h>
 #include <pxr/imaging/hgi/hgi.h>
 #include <pxr/imaging/hgi/tokens.h>
+#include <pxr/usd/kind/registry.h>
+#include <pxr/usd/usd/prim.h>
+#include <pxr/usd/usd/modelAPI.h>
 #include <pxr/pxr.h>
 
+#include <mayaUsdAPI/proxyStage.h>
+
 #include <maya/M3dView.h>
 #include <maya/MConditionMessage.h>
 #include <maya/MDGMessage.h>
@@ -164,6 +169,45 @@ PXR_NAMESPACE_USING_DIRECTIVE
 
 static const SdfPath MAYA_NATIVE_ROOT = SdfPath("/MayaHydraViewportRenderer");
 
+// Copy pasted from
+// https://github.com/Autodesk/maya-usd/blob/dev/lib/mayaUsd/render/vp2RenderDelegate/proxyRenderDelegate.cpp
+
+//! \brief  Query the Kind to be selected from viewport.
+//! \return A Kind token (https://graphics.pixar.com/usd/docs/api/kind_page_front.html). If the
+//!         token is empty or non-existing in the hierarchy, the exact prim that gets picked
+//!         in the viewport will be selected.
+TfToken GetSelectionKind()
+{
+    static const MString kOptionVarName(MayaUsdPickOptionVars->SelectionKind.GetText());
+
+    if (MGlobal::optionVarExists(kOptionVarName)) {
+        MString optionVarValue = MGlobal::optionVarStringValue(kOptionVarName);
+        return TfToken(optionVarValue.asChar());
+    }
+    return TfToken();
+}
+
+//! \brief  Returns the prim or an ancestor of it that is of the given kind.
+//
+// If neither the prim itself nor any of its ancestors above it in the
+// namespace hierarchy have an authored kind that matches, an invalid null
+// prim is returned.
+UsdPrim GetPrimOrAncestorWithKind(const UsdPrim& prim, const TfToken& kind)
+{
+    UsdPrim iterPrim = prim;
+    TfToken primKind;
+
+    while (iterPrim) {
+        if (UsdModelAPI(iterPrim).GetKind(&primKind) && KindRegistry::IsA(primKind, kind)) {
+            break;
+        }
+
+        iterPrim = iterPrim.GetParent();
+    }
+
+    return iterPrim;
+}
+
 //! Pick resolution behavior to use when the picked object is a point instance.
 enum UsdPointInstancesPickMode
 {
@@ -287,6 +331,15 @@ HitPath pickInstancer(
     return {instancerPrimOrigin(primOrigin.instancerContexts.front()), -1};
 }
 
+Ufe::Path usdPathToUfePath(
+    const MayaHydraSceneIndexRegistrationPtr& registration,
+    const SdfPath&                            usdPath
+)
+{
+    return registration ? registration->interpretRprimPathFn(
+        registration->pluginSceneIndex, usdPath) : Ufe::Path();
+}
+
 }
 
 PXR_NAMESPACE_OPEN_SCOPE
@@ -445,19 +498,48 @@ class UsdPickHandler : public MtohRenderOverride::PickHandlerBase {
 
         // For the USD pick handler pick results are directly returned with USD
         // scene paths, so no need to remove scene index plugin path prefix.
-        const auto& [pickedPath, instanceNdx] = hitPath(pickInput.pickHit);
-        Ufe::Path interpretedPath(registration->interpretRprimPathFn(
-            registration->pluginSceneIndex, pickedPath));
-
-        // Appending a numeric component to the path to identify a point
-        // instance cannot be done on the picked SdfPath, as numeric path
-        // components are not allowed by SdfPath.  Do so here with Ufe::Path,
-        // which has no such restriction.
-        if (instanceNdx >= 0) {
-            interpretedPath = interpretedPath + std::to_string(instanceNdx);
-        }
+        const auto& [pickedUsdPath, instanceNdx] = hitPath(pickInput.pickHit);
+
+        const auto pickedMayaPath = usdPathToUfePath(registration, pickedUsdPath);
+        const auto snMayaPath =
+            // As per https://stackoverflow.com/questions/46114214
+            // structured bindings cannot be captured by a lambda in C++ 17,
+            // so pass in pickedUsdPath and instanceNdx as lambda arguments.
+            [&pickedMayaPath, &registration](
+                const SdfPath& pickedUsdPath, int instanceNdx) {
+
+            if (instanceNdx >= 0) {
+                // Point instance: add the instance index to the path.
+                // Appending a numeric component to the path to identify a
+                // point instance cannot be done on the picked SdfPath, as
+                // numeric path components are not allowed by SdfPath.  Do so
+                // here with Ufe::Path, which has no such restriction.
+                return pickedMayaPath + std::to_string(instanceNdx);
+            }
+
+            // Not an instance: adjust picked path for selection kind.
+            auto snKind = GetSelectionKind();
+            if (snKind.IsEmpty()) {
+                return pickedMayaPath;
+            }
+
+            // Get the prim from the stage and path, to access the
+            // UsdModelAPI for the prim.
+            auto proxyShapeObj = registration->dagNode.object();
+            if (proxyShapeObj.isNull()) {
+                TF_FATAL_ERROR("No mayaUsd proxy shape object corresponds to USD pick");
+                return pickedMayaPath;
+            }
+
+            MayaUsdAPI::ProxyStage proxyStage{proxyShapeObj};
+            auto prim = proxyStage.getUsdStage()->GetPrimAtPath(pickedUsdPath);
+            prim = GetPrimOrAncestorWithKind(prim, snKind);
+            const auto usdPath = prim ? prim.GetPath() : pickedUsdPath;
+
+            return usdPathToUfePath(registration, usdPath);
+        }(pickedUsdPath, instanceNdx);
 
-        auto si = Ufe::Hierarchy::createItem(interpretedPath);
+        auto si = Ufe::Hierarchy::createItem(snMayaPath);
         if (!si) {
             return false;
         }

test/lib/mayaUsd/render/mayaToHydra/CMakeLists.txt

@@ -47,8 +47,9 @@ set(INTERACTIVE_TEST_SCRIPT_FILES
     cpp/testSceneCorrectness.py
     cpp/testPrimInstancing.py
     cpp/testPicking.py
-    cpp/testPointInstancePicking.py
+    cpp/testUsdPointInstancePicking.py
     cpp/testUsdNativeInstancePicking.py
+    cpp/testUsdPickKind.py
 )
 
 #Add this test only if the MayaUsd_FOUND (so also MAYAUSDAPI_LIBRARY) has been found during compile time.

test/lib/mayaUsd/render/mayaToHydra/cpp/CMakeLists.txt

@@ -35,8 +35,8 @@ target_sources(${TARGET_NAME}
         testSceneCorrectness.cpp
         testPrimInstancing.cpp
         testPicking.cpp
-        testPointInstancePicking.cpp
-        testUsdNativeInstancePicking.cpp
+        testUsdPointInstancePicking.cpp
+        testUsdPicking.cpp
 )
 
 # -----------------------------------------------------------------------------

test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdNativeInstancePicking.py

@@ -41,7 +41,7 @@ def test_NativeInstances(self):
             for instance in instances:
                 cmds.mayaHydraCppTest(
                     self.PICK_PATH + instance,
-                    f="TestUsdNativeInstancePicking.pickInstance")
+                    f="TestUsdPicking.pick")
 
 if __name__ == '__main__':
     fixturesUtils.runTests(globals())

test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdPickKind.py

@@ -0,0 +1,73 @@
+# Copyright 2024 Autodesk
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+import maya.cmds as cmds
+import fixturesUtils
+import mtohUtils
+import usdUtils
+
+import testUtils
+from testUtils import PluginLoaded
+
+class TestUsdPickKind(mtohUtils.MayaHydraBaseTestCase):
+    # MayaHydraBaseTestCase.setUpClass requirement.
+    _file = __file__
+
+    PICK_PATH = "|kindHierarchy|kindHierarchyShape,/RootAssembly/ParentGroup"
+
+    def loadUsdScene(self):
+        usdScenePath = testUtils.getTestScene('testUsdPickKind', 'kindHierarchy.usda')
+        usdUtils.createStageFromFile(usdScenePath)
+
+    def setUp(self):
+        super(TestUsdPickKind, self).setUp()
+        self.loadUsdScene()
+        cmds.refresh()
+
+    def test_pickKinds(self):
+        with PluginLoaded('mayaHydraCppTests'):
+            kinds = ["", "model", "group", "assembly", "component", "subcomponent"]
+            selectedItems = [
+                # Kind is none: pick the most descendant prim.
+                "/ChildAssembly/LeafModel/ImportantSubtree/Cube",
+                # Kind is model: subcomponent is not part of the model kind
+                # hierarchy, so we iterate up the parent hierarchy twice to
+                # reach the component prim.
+                "/ChildAssembly/LeafModel",
+                # Kind is group: an assembly is a group, so ChildAssembly is
+                # picked.
+                "/ChildAssembly",
+                # Kind is assembly.
+                "/ChildAssembly",
+                # Kind is component
+                "/ChildAssembly/LeafModel",
+                # Kind is subcomponent
+                "/ChildAssembly/LeafModel/ImportantSubtree"
+            ]
+
+            # Read the current USD selection kind.
+            kindOptionVar = "mayaUsd_SelectionKind"
+            previousKind = cmds.optionVar(q=kindOptionVar)
+
+            for (kind, selectedItem) in zip(kinds, selectedItems):
+                cmds.optionVar(sv=(kindOptionVar, kind))
+                cmds.mayaHydraCppTest(
+                    self.PICK_PATH + selectedItem,
+                    f="TestUsdPicking.pick")
+
+            # Restore the USD selection kind back to its original value.
+            cmds.optionVar(sv=(kindOptionVar, previousKind))
+
+if __name__ == '__main__':
+    fixturesUtils.runTests(globals())

test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdNativeInstancePicking.cpp → test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdPicking.cpp

@@ -32,7 +32,7 @@ PXR_NAMESPACE_USING_DIRECTIVE
 
 using namespace MayaHydra;
 
-TEST(TestUsdNativeInstancePicking, pickInstance)
+TEST(TestUsdPicking, pick)
 {
     const auto& sceneIndices = GetTerminalSceneIndices();
     ASSERT_GT(sceneIndices.size(), 0u);

test/lib/mayaUsd/render/mayaToHydra/cpp/testPointInstancePicking.cpp → test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdPointInstancePicking.cpp

@@ -29,7 +29,7 @@ PXR_NAMESPACE_USING_DIRECTIVE
 
 using namespace MayaHydra;
 
-TEST(TestPointInstancePicking, pickPointInstance)
+TEST(TestUsdPointInstancePicking, pickPointInstance)
 {
     const auto& sceneIndices = GetTerminalSceneIndices();
     ASSERT_GT(sceneIndices.size(), 0u);

test/lib/mayaUsd/render/mayaToHydra/cpp/testPointInstancePicking.py → test/lib/mayaUsd/render/mayaToHydra/cpp/testUsdPointInstancePicking.py

@@ -20,7 +20,7 @@
 import testUtils
 from testUtils import PluginLoaded
 
-class TestPointInstancePicking(mtohUtils.MayaHydraBaseTestCase):
+class TestUsdPointInstancePicking(mtohUtils.MayaHydraBaseTestCase):
     # MayaHydraBaseTestCase.setUpClass requirement.
     _file = __file__
 
@@ -34,11 +34,11 @@ class TestPointInstancePicking(mtohUtils.MayaHydraBaseTestCase):
     # we want to pick, and use the marker objects to determine the projected
     # mouse coordinates.
     def loadUsdScene(self):
-        usdScenePath = testUtils.getTestScene('testPointInstances', 'nestedPointInstancers.usda')
+        usdScenePath = testUtils.getTestScene('testUsdPointInstances', 'nestedPointInstancers.usda')
         usdUtils.createStageFromFile(usdScenePath)
 
     def setUp(self):
-        super(TestPointInstancePicking, self).setUp()
+        super(TestUsdPointInstancePicking, self).setUp()
         self.loadUsdScene()
         cmds.setAttr('persp.translate', 19.3, 13.7, 11.4, type='float3')
         cmds.setAttr('persp.rotate', -33.4, 63.0, 0, type='float3')
@@ -59,7 +59,7 @@ def test_PickPointInstancer(self):
                 cmds.mayaHydraCppTest(
                     self.PICK_PATH + "/ParentPointInstancer",
                     self.PICK_PATH + marker,
-                    f="TestPointInstancePicking.pickPointInstance")
+                    f="TestUsdPointInstancePicking.pickPointInstance")
 
     def test_PickInstances(self):
         with PluginLoaded('mayaHydraCppTests'):
@@ -82,7 +82,7 @@ def test_PickInstances(self):
                 cmds.mayaHydraCppTest(
                     self.PICK_PATH + instance,
                     self.PICK_PATH + marker,
-                    f="TestPointInstancePicking.pickPointInstance")
+                    f="TestUsdPointInstancePicking.pickPointInstance")
 
     def test_PickPrototypes(self):
         with PluginLoaded('mayaHydraCppTests'):
@@ -106,7 +106,7 @@ def test_PickPrototypes(self):
                 cmds.mayaHydraCppTest(
                     self.PICK_PATH + prototype,
                     self.PICK_PATH + marker,
-                    f="TestPointInstancePicking.pickPointInstance")
+                    f="TestUsdPointInstancePicking.pickPointInstance")
 
 if __name__ == '__main__':
     fixturesUtils.runTests(globals())

test/testSamples/testUsdPickKind/kindHierarchy.usda

@@ -0,0 +1,35 @@
+#usda 1.0
+
+def Xform "RootAssembly" (
+    kind = "assembly"
+)
+{
+    def Xform "ParentGroup" (
+        kind = "group"
+    )
+    {
+        def Xform "ChildAssembly" (
+            kind = "assembly"
+        )
+        {
+            def Xform "LeafModel" (
+                kind = "component"
+            )
+            {
+                def Xform "ImportantSubtree" (
+                    kind = "subcomponent"
+                )
+                {
+                    def Mesh "Cube"
+                    {
+                        float3[] extent = [(-0.5, -0.5, -0.5), (0.5, 0.5, 0.5)]
+                        int[] faceVertexCounts = [4, 4, 4, 4, 4, 4]
+                        int[] faceVertexIndices = [0, 1, 3, 2, 2, 3, 5, 4, 4, 5, 7, 6, 6, 7, 1, 0, 1, 7, 5, 3, 6, 0, 2, 4]
+                        point3f[] points = [(-0.5, -0.5, 0.5), (0.5, -0.5, 0.5), (-0.5, 0.5, 0.5), (0.5, 0.5, 0.5), (-0.5, 0.5, -0.5), (0.5, 0.5, -0.5), (-0.5, -0.5, -0.5), (0.5, -0.5, -0.5)]
+                        uniform token subdivisionScheme = "none"
+                    }
+                }
+            }
+        }
+    }
+}