[ui] introduce Scene3DHelper object

Expose missing QEntity methods and helper functions to QML via this Python class.

meshroom/ui/app.py

@@ -9,6 +9,7 @@ import meshroom
 from meshroom.core import nodesDesc
 from meshroom.ui import components
 from meshroom.ui.components.filepath import FilepathHelper
+from meshroom.ui.components.scene3D import Scene3DHelper
 from meshroom.ui.palette import PaletteManager
 from meshroom.ui.reconstruction import Reconstruction
 from meshroom.ui.utils import QmlInstantEngine
@@ -51,6 +52,8 @@ class MeshroomApp(QApplication):
         self.engine.rootContext().setContextProperty("_PaletteManager", pm)
         fpHelper = FilepathHelper(parent=self)
         self.engine.rootContext().setContextProperty("Filepath", fpHelper)
+        scene3DHelper = Scene3DHelper(parent=self)
+        self.engine.rootContext().setContextProperty("Scene3DHelper", scene3DHelper)
         self.engine.rootContext().setContextProperty("MeshroomApp", self)
         # Request any potential computation to stop on exit
         self.aboutToQuit.connect(r.stopExecution)

meshroom/ui/components/__init__.py

@@ -3,7 +3,8 @@ def registerTypes():
     from PySide2.QtQml import qmlRegisterType
     from meshroom.ui.components.edge import EdgeMouseArea
     from meshroom.ui.components.filepath import FilepathHelper
+    from meshroom.ui.components.scene3D import Scene3DHelper
 
     qmlRegisterType(EdgeMouseArea, "GraphEditor", 1, 0, "EdgeMouseArea")
     qmlRegisterType(FilepathHelper, "Meshroom.Helpers", 1, 0, "FilepathHelper")  # TODO: uncreatable
-
+    qmlRegisterType(Scene3DHelper, "Meshroom.Helpers", 1, 0, "Scene3DHelper")  # TODO: uncreatable

meshroom/ui/components/scene3D.py

@@ -0,0 +1,42 @@
+from PySide2.QtCore import QObject, Slot
+from PySide2.Qt3DCore import Qt3DCore
+from PySide2.Qt3DRender import Qt3DRender
+
+
+class Scene3DHelper(QObject):
+
+    @Slot(Qt3DCore.QEntity, str, result="QVariantList")
+    def findChildrenByProperty(self, entity, propertyName):
+        """ Recursively get all children of an entity that have a property named 'propertyName'. """
+        children = []
+        for child in entity.childNodes():
+            try:
+                if child.metaObject().indexOfProperty(propertyName) != -1:
+                    children.append(child)
+            except RuntimeError:
+                continue
+            children += self.findChildrenByProperty(child, propertyName)
+        return children
+
+    @Slot(Qt3DCore.QEntity, Qt3DCore.QComponent)
+    def addComponent(self, entity, component):
+        """ Adds a component to an entity. """
+        entity.addComponent(component)
+
+    @Slot(Qt3DCore.QEntity, Qt3DCore.QComponent)
+    def removeComponent(self, entity, component):
+        """ Removes a component from an entity. """
+        entity.removeComponent(component)
+
+    @Slot(Qt3DCore.QEntity, result=int)
+    def vertexCount(self, entity):
+        """ Return vertex count based on children QGeometryRenderer 'vertexCount'."""
+        return sum([renderer.vertexCount() for renderer in entity.findChildren(Qt3DRender.QGeometryRenderer)])
+
+    @Slot(Qt3DCore.QEntity, result=int)
+    def faceCount(self, entity):
+        """ Returns face count based on children QGeometry buffers size."""
+        count = 0
+        for geo in entity.findChildren(Qt3DRender.QGeometry):
+            count += sum([attr.count() for attr in geo.attributes() if attr.name() == "vertexPosition"])
+        return count / 3

meshroom/ui/qml/Utils/Scene3DHelper.qml

@@ -0,0 +1,6 @@
+pragma Singleton
+import Meshroom.Helpers 1.0
+
+Scene3DHelper {
+
+}

meshroom/ui/qml/Utils/qmldir

@@ -4,3 +4,4 @@ SortFilterDelegateModel 1.0 SortFilterDelegateModel.qml
 Request 1.0 request.js
 # causes random crash at application exit
 # singleton Filepath 1.0 Filepath.qml
+# singleton Scene3DHelper 1.0 Scene3DHelper.qml