uLib/src/Math/Assembly.cpp

/*//////////////////////////////////////////////////////////////////////////////
// CMT Cosmic Muon Tomography project //////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

  Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
  All rights reserved

  Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >

//////////////////////////////////////////////////////////////////////////////*/

#include "Math/Assembly.h"
#include "Math/ContainerBox.h"
#include "Math/Cylinder.h"

#include <limits>
#include <algorithm>
#include <cstring>

namespace uLib {

Assembly::Assembly()
    : ObjectsContext(),
      TRS(),
      m_BBoxMin(Vector3f::Zero()),
      m_BBoxMax(Vector3f::Zero()),
      m_ShowBoundingBox(false),
      m_GroupSelection(true) {
    ULIB_ACTIVATE_PROPERTIES(*this);
}

Assembly::Assembly(const Assembly &copy)
    : ObjectsContext(copy),
      TRS(copy),
      m_BBoxMin(copy.m_BBoxMin),
      m_BBoxMax(copy.m_BBoxMax),
      m_ShowBoundingBox(copy.m_ShowBoundingBox),
      m_GroupSelection(copy.m_GroupSelection) {}

Assembly::~Assembly() {
    for (auto const& [obj, conn] : m_ChildConnections) {
        conn.disconnect();
    }
    m_ChildConnections.clear();
}

void Assembly::AddObject(Object *obj) {
    if (auto *at = dynamic_cast<AffineTransform *>(obj)) {
        at->SetParent(this);
    }
    ObjectsContext::AddObject(obj);
    
    // Connect to child updates to recompute AABB
    m_ChildConnections[obj] = Object::connect(obj, &Object::Updated, [this](){
        this->ComputeBoundingBox();
        this->Updated(); // Signal that assembly itself changed (AABB-wise)
    });

    // Parent -> Child propagation for world matrix updates
    Object::connect(this, &Object::Updated, obj, &Object::Updated);

    this->ComputeBoundingBox();
}

void Assembly::RemoveObject(Object *obj) {
    if (auto *at = dynamic_cast<AffineTransform *>(obj)) {
        if (at->GetParent() == this)
            at->SetParent(nullptr);
    }
    
    auto itConn = m_ChildConnections.find(obj);
    if (itConn != m_ChildConnections.end()) {
        itConn->second.disconnect();
        m_ChildConnections.erase(itConn);
    }
    
    ObjectsContext::RemoveObject(obj);
    this->ComputeBoundingBox();
}

void Assembly::ComputeBoundingBox() {
    const auto &objects = this->GetObjects();
    if (objects.empty()) {
        m_BBoxMin = Vector3f::Zero();
        m_BBoxMax = Vector3f::Zero();
        return;
    }

    float inf = std::numeric_limits<float>::max();
    m_BBoxMin = Vector3f(inf, inf, inf);
    m_BBoxMax = Vector3f(-inf, -inf, -inf);

    for (Object *obj : objects) {
        if (auto *box = dynamic_cast<ContainerBox *>(obj)) {
            // ContainerBox: wm is matrix from unit cube [0,1] to local space
            // Since it is parented to 'this', GetMatrix() is sufficient.
            Matrix4f m = box->GetMatrix();
            for (int i = 0; i < 8; ++i) {
                float x = (i & 1) ? 1.0f : 0.0f;
                float y = (i & 2) ? 1.0f : 0.0f;
                float z = (i & 4) ? 1.0f : 0.0f;
                Vector4f corner = m * Vector4f(x, y, z, 1.0f);
                for (int a = 0; a < 3; ++a) {
                    m_BBoxMin(a) = std::min(m_BBoxMin(a), corner(a));
                    m_BBoxMax(a) = std::max(m_BBoxMax(a), corner(a));
                }
            }
        } else if (auto *cyl = dynamic_cast<Cylinder *>(obj)) {
            // Cylinder: centered [-1, 1] radial, [-0.5, 0.5] height
            Matrix4f m = cyl->GetMatrix();
            for (int i = 0; i < 8; ++i) {
                float x = (i & 1) ? 1.0f : -1.0f;
                float y = (i & 2) ? 0.5f : -0.5f;
                float z = (i & 4) ? 1.0f : -1.0f;
                Vector4f corner = m * Vector4f(x, y, z, 1.0f);
                for (int a = 0; a < 3; ++a) {
                    m_BBoxMin(a) = std::min(m_BBoxMin(a), corner(a));
                    m_BBoxMax(a) = std::max(m_BBoxMax(a), corner(a));
                }
            }
        } else if (auto *subAsm = dynamic_cast<Assembly *>(obj)) {
            // Recursive AABB for nested assemblies
            subAsm->ComputeBoundingBox();
            Vector3f subMin, subMax;
            subAsm->GetBoundingBox(subMin, subMax);
            Matrix4f m = subAsm->GetMatrix();
            for (int i = 0; i < 8; ++i) {
                float x = (i & 1) ? subMax(0) : subMin(0);
                float y = (i & 2) ? subMax(1) : subMin(1);
                float z = (i & 4) ? subMax(2) : subMin(2);
                Vector4f corner = m * Vector4f(x, y, z, 1.0f);
                for (int a = 0; a < 3; ++a) {
                    m_BBoxMin(a) = std::min(m_BBoxMin(a), corner(a));
                    m_BBoxMax(a) = std::max(m_BBoxMax(a), corner(a));
                }
            }
        }
    }
}

void Assembly::GetBoundingBox(Vector3f &bbMin, Vector3f &bbMax) const {
    bbMin = m_BBoxMin;
    bbMax = m_BBoxMax;
}

ContainerBox Assembly::GetBoundingBoxAsContainer() const {
    ContainerBox bb;
    Vector3f size = m_BBoxMax - m_BBoxMin;
    bb.SetSize(size);
    bb.SetPosition(m_BBoxMin);
    return bb;
}

void Assembly::SetShowBoundingBox(bool show) {
    m_ShowBoundingBox = show;
    this->Updated();
}

bool Assembly::GetShowBoundingBox() const {
    return m_ShowBoundingBox;
}

void Assembly::SetGroupSelection(bool group) {
    m_GroupSelection = group;
}

bool Assembly::GetGroupSelection() const {
    return m_GroupSelection;
}

} // namespace uLib