[Simulation.Core] Fix BoundingBox initialization and updates (#6146)

* add a boolean to track bounding box value, and use this state at init to compute bbox (or not)

* make it protected

---------

Co-authored-by: erik pernod <erik.pernod@gmail.com>

Author: fredroy

Sofa/framework/Simulation/Core/src/sofa/simulation/InitVisitor.cpp

@@ -37,14 +37,15 @@ Visitor::Result InitVisitor::processNodeTopDown(simulation::Node* node)
     node->initialize();
 
     sofa::type::BoundingBox* nodeBBox = node->f_bbox.beginEdit();
-    if(!node->f_bbox.isSet())
+    if(!node->bboxIsFixed())
         nodeBBox->invalidate();
 
     for(unsigned int i=0; i<node->object.size(); ++i)
     {
         node->object[i]->init();
         node->object[i]->computeBBox(params, true);
-        nodeBBox->include(node->object[i]->f_bbox.getValue());
+        if(!node->bboxIsFixed())
+            nodeBBox->include(node->object[i]->f_bbox.getValue());
     }
     node->f_bbox.endEdit();
     return RESULT_CONTINUE;
@@ -60,7 +61,8 @@ void InitVisitor::processNodeBottomUp(simulation::Node* node)
     for(std::size_t i=node->object.size(); i>0; --i)
     {
         node->object[i-1]->bwdInit();
-        nodeBBox->include(node->object[i-1]->f_bbox.getValue());
+        if(!node->bboxIsFixed())
+            nodeBBox->include(node->object[i-1]->f_bbox.getValue());
     }
 
     node->f_bbox.endEdit();

Sofa/framework/Simulation/Core/src/sofa/simulation/Node.cpp

@@ -191,6 +191,13 @@ void Node::parse( sofa::core::objectmodel::BaseObjectDescription* arg )
         objDesc.setAttribute("displayFlags", oldFlags);
         sofa::core::objectmodel::BaseComponent::SPtr obj = sofa::core::ObjectFactory::CreateObject(this, &objDesc);
     }
+    
+    // BoundingBox state management
+    const char* bboxAttrStr = arg->getAttribute("bbox", nullptr);
+    if(bboxAttrStr != nullptr)
+    {
+        this->m_bboxIsFixed = true;
+    }
 }
 
 /// Initialize the components of this node and all the nodes which depend on it.

Sofa/framework/Simulation/Core/src/sofa/simulation/Node.h

@@ -555,10 +555,12 @@ class SOFA_SIMULATION_CORE_API Node : public sofa::core::objectmodel::BaseNode,
 
     /// return the smallest common parent between this and node2 (returns nullptr if separated sub-graphes)
     Node* findCommonParent( simulation::Node* node2 );
-
+    
+    bool bboxIsFixed() const { return m_bboxIsFixed; }
 protected:
     bool debug_;
     bool initialized;
+    bool m_bboxIsFixed{false};
 
     virtual bool doAddObject(sofa::core::objectmodel::BaseComponent::SPtr obj,  sofa::core::objectmodel::TypeOfInsertion insertionLocation= sofa::core::objectmodel::TypeOfInsertion::AtEnd);
     virtual bool doRemoveObject(sofa::core::objectmodel::BaseComponent::SPtr obj);

Sofa/framework/Simulation/Core/src/sofa/simulation/UpdateBoundingBoxVisitor.cpp

@@ -41,7 +41,7 @@ Visitor::Result UpdateBoundingBoxVisitor::processNodeTopDown(Node* node)
     type::vector<BaseObject*>::iterator object;
     node->get<BaseObject>(&objectList,BaseContext::Local);
     sofa::type::BoundingBox* nodeBBox = node->f_bbox.beginEdit();
-    if(!node->f_bbox.isSet()) // bmarques: Without invalidating the bbox, the node's bbox will only be sized up, and never down with this visitor, to my understanding..
+    if(!node->bboxIsFixed()) // bmarques: Without invalidating the bbox, the node's bbox will only be sized up, and never down with this visitor, to my understanding..
         nodeBBox->invalidate();
     for ( object = objectList.begin(); object != objectList.end(); ++object)
     {
@@ -53,22 +53,31 @@ Visitor::Result UpdateBoundingBoxVisitor::processNodeTopDown(Node* node)
         // if some objects does not participate to the bounding box where they should,
         // you should overload their computeBBox function to correct that
         (*object)->computeBBox(params, true);
-
-        nodeBBox->include((*object)->f_bbox.getValue());
+        
+        if(!node->bboxIsFixed())
+            nodeBBox->include((*object)->f_bbox.getValue());
     }
     node->f_bbox.endEdit();
     return RESULT_CONTINUE;
 }
 
 void UpdateBoundingBoxVisitor::processNodeBottomUp(simulation::Node* node)
 {
-    sofa::type::BoundingBox* nodeBBox = node->f_bbox.beginEdit();
-    Node::ChildIterator childNode;
-    for( childNode = node->child.begin(); childNode!=node->child.end(); ++childNode)
+    if(!node->bboxIsFixed())
     {
-        nodeBBox->include((*childNode)->f_bbox.getValue());
+        sofa::type::BoundingBox* nodeBBox = node->f_bbox.beginEdit();
+        Node::ChildIterator childNode;
+        for( childNode = node->child.begin(); childNode!=node->child.end(); ++childNode)
+        {
+            nodeBBox->include((*childNode)->f_bbox.getValue());
+        }
+        node->f_bbox.endEdit();
     }
-    node->f_bbox.endEdit();
+    else
+    {
+        // the node bounding box is supposed to be fixed
+    }
+        
 }
 
 }