REveProjectionManager.cxx

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// @(#)root/eve7:$Id$
// Authors: Matevz Tadel & Alja Mrak-Tadel: 2006, 2007
 
/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include <ROOT/REveProjectionManager.hxx>
#include <ROOT/REveManager.hxx>
#include <ROOT/REveProjectionBases.hxx>
#include <ROOT/REveCompound.hxx>
#include <ROOT/REveScene.hxx>
#include <ROOT/REveTrans.hxx>
 
#include "TBuffer3D.h"
#include "TBuffer3DTypes.h"
 
#include "TClass.h"
 
#include <algorithm>
#include <cmath>
#include <cstring>
#include <functional>
 
#include <list>
 
/** \class REveProjectionManager
\ingroup REve
Manager class for steering of projections and managing projected objects.
 
Recursively projects REveElement's and draws axis in the projected
scene. It enables to interactively set REveProjection parameters
and updates projected scene accordingly.
*/
 
using namespace ROOT::Experimental;
namespace REX = ROOT::Experimental;
 
namespace {
 
////////////////////////////////////////////////////////////////////////////////
/// Warn if `el` has a transformation other than identity. The vertices of a
/// projected element are final, so the client must not transform them again.
/// Identity is allowed: REveStraightLineSet's constructor sets one.
 
void WarnIfTransformed(REveElement *el)
{
   static const REveTrans unit;
   if (el->HasMainTrans() && std::memcmp(el->RefMainTrans().Array(), unit.Array(), 16 * sizeof(Double_t)) != 0) {
      ::Warning("REveProjectionManager::ImportElements",
                "'%s' has a transformation, which the client applies to its projected vertices again.", el->GetCName());
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Warn if projected elements put under `receiver` are drawn in a frame other
/// than that of `mng`. GetModelTrans() projects into the frame of the manager,
/// and the client places the projected elements with the matrices of
/// `receiver` and of its mothers, so the two products must be equal.
 
void WarnIfFrameDiffers(REveProjectionManager *mng, REveElement *receiver)
{
   REveTrans wm, wr;
   const int nm = mng->ComposeSceneTrans(wm);
   const int nr = receiver->ComposeSceneTrans(wr);
   if (nm == 0 && nr == 0)
      return;
 
   // Tolerance for the rounding of the inversion, relative to the translations.
   Double_t scale = 1;
   for (int i = 12; i < 15; ++i)
      scale = std::max({scale, std::abs(wm.Array()[i]), std::abs(wr.Array()[i])});
 
   // d = inverse(W(manager)) * W(receiver), the identity when the frames agree.
   REveTrans d;
   if (nm > 0) {
      wm.Invert();
      d = wm;
      if (nr > 0)
         d.MultRight(wr);
   } else {
      d = wr;
   }
 
   static const REveTrans unit;
   for (int i = 0; i < 16; ++i) {
      if (std::abs(d.Array()[i] - unit.Array()[i]) > 1e-6 * scale) {
         ::Warning("REveProjectionManager::ImportElements",
                   "'%s' places projected elements in a frame other than that of '%s', in which they are "
                   "projected; the client draws them transformed.",
                   receiver->GetCName(), mng->GetCName());
         return;
      }
   }
}
 
} // namespace
 
////////////////////////////////////////////////////////////////////////////////
/// Constructor.
 
REveProjectionManager::REveProjectionManager(REveProjection::EPType_e type):
   REveElement("REveProjectionManager","")
{
   for (Int_t i = 0; i < REveProjection::kPT_End; ++i)
      fProjections[i] = nullptr;
 
   if (type != REveProjection::kPT_Unknown)
      SetProjection(type);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Destructor.
/// Destroys also dependent elements.
 
REveProjectionManager::~REveProjectionManager()
{
   for (Int_t i = 0; i < REveProjection::kPT_End; ++i) {
      delete fProjections[i];
   }
   while ( ! fDependentEls.empty()) {
      fDependentEls.front()->Destroy();
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add el as dependent element.
 
void REveProjectionManager::AddDependent(REveElement *el)
{
   fDependentEls.push_back(el);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Remove el as dependent element.
 
void REveProjectionManager::RemoveDependent(REveElement *el)
{
   fDependentEls.remove(el);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Updates name to have consistent information with projection.
 
////////////////////////////////////////////////////////////////////////////////
/// Add `steps` * 1e-4 to the distortion of the current projection, clamped at
/// zero, and reproject, which also refreshes the REveProjectionAxis nieces.
/// Called by MIR.
 
void REveProjectionManager::BumpDistortion(Int_t steps)
{
   if (!fProjection)
      return;
 
   Float_t d = fProjection->GetDistortion() + steps * 1e-4f;
   if (d < 0.f)
      d = 0.f;
   fProjection->SetDistortion(d);
 
   UpdateName();
   ProjectChildren();
}
 
void REveProjectionManager::UpdateName()
{
   if (fProjection->Is2D())
      SetName(Form ("%s (%3.1f)", fProjection->GetName(), fProjection->GetDistortion()*1000));
   else
      SetName(fProjection->GetName());
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set projection type and distortion.
 
void REveProjectionManager::SetProjection(REveProjection::EPType_e type)
{
   static const REveException eH("REveProjectionManager::SetProjection ");
 
   if (fProjections[type] == nullptr)
   {
      switch (type)
      {
         case REveProjection::kPT_RhoZ:
         {
            fProjections[type] = new REveRhoZProjection();
            break;
         }
         case REveProjection::kPT_RPhi:
         {
            fProjections[type] = new REveRPhiProjection();
            break;
         }
         case REveProjection::kPT_XZ:
         {
            fProjections[type] = new REveXZProjection();
            break;
         }
         case REveProjection::kPT_YZ:
         {
            fProjections[type] = new REveYZProjection();
            break;
         }
         case REveProjection::kPT_ZX:
         {
            fProjections[type] = new REveZXProjection();
            break;
         }
         case REveProjection::kPT_ZY:
         {
            fProjections[type] = new REveZYProjection();
            break;
         }
         case REveProjection::kPT_3D:
         {
            fProjections[type] = new REve3DProjection();
            break;
         }
         default:
            throw eH + "projection type not valid.";
            break;
      }
   }
 
   if (fProjection && fProjection->Is2D() != fProjections[type]->Is2D())
   {
      throw eH + "switching between 2D and 3D projections not implemented.";
   }
 
   fProjection = fProjections[type];
   fProjection->SetCenter(fCenter);
   UpdateName();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set projection center and rebuild projected scene.
 
void REveProjectionManager::SetCenter(Float_t x, Float_t y, Float_t z)
{
   fCenter.Set(x, y, z);
   fProjection->SetCenter(fCenter);
   ProjectChildren();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Returns true if element el should be imported.
///
/// Behaviour depends on the value of the fImportEmpty member:
///   false - el or any of its children must be projectable (default);
///   true  - always import.
 
Bool_t REveProjectionManager::ShouldImport(REveElement *el)
{
   if (fImportEmpty)
      return kTRUE;
 
   if (el->IsA()->InheritsFrom(TClass::GetClass<REveProjectable>()))
      return kTRUE;
   for (auto &c: el->RefChildren())
      if (ShouldImport(c))
         return kTRUE;
   return kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Update dependent elements' bounding boxes, and tell the nieces, such as an
/// REveProjectionAxis, that the manager changed. Called after every import and
/// reprojection.
 
void REveProjectionManager::UpdateDependentElements(REveElement * /*root*/)
{
   for (auto &d : fDependentEls)
      d->ComputeBBox();
 
   for (auto &n : fNieces)
      n->AuntChanged(this);
}
 
////////////////////////////////////////////////////////////////////////////////
/// If el is REveProjectable add projected instance else add plain
/// REveElementList to parent. Call the same function on el's
/// children.
///
/// Returns the projected replica of el. Can be 0, if el and none of
/// its children are projectable.
 
REveElement* REveProjectionManager::ImportElementsRecurse(REveElement* el,
                                                          REveElement* parent)
{
   static const REveException eh("REveProjectionManager::ImportElementsRecurse ");
 
   REveElement *new_el = nullptr;
 
   if (ShouldImport(el))
   {
      REveProjected   *new_pr = nullptr;
      REveProjectable *pble   = dynamic_cast<REveProjectable*>(el);
      if (pble)
      {
         new_el = (REveElement*) pble->ProjectedClass(fProjection)->New();
         new_pr = dynamic_cast<REveProjected*>(new_el);
         new_pr->SetProjection(this, pble);
         new_pr->SetDepth(fCurrentDepth);
      }
      else
      {
         new_el = new REveElement;
      }
      new_el->SetName (Form("%s [P]", el->GetCName()));
      new_el->SetTitle(Form("Projected replica.\n%s", el->GetCTitle()));
      new_el->SetRnrSelf     (el->GetRnrSelf());
      new_el->SetRnrChildren (el->GetRnrChildren());
      new_el->SetPickable    (el->IsPickable());
 
      parent->AddElement(new_el);
      WarnIfTransformed(new_el);
 
      REveCompound *cmpnd    = dynamic_cast<REveCompound*>(el);
      REveCompound *cmpnd_pr = dynamic_cast<REveCompound*>(new_el);
      for (auto &c: el->RefChildren()) {
         REveElement *child_pr = ImportElementsRecurse(c, new_el);
         if (cmpnd && c->GetCompound() == cmpnd)
            child_pr->SetCompound(cmpnd_pr);
      }
   }
 
   return new_el;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Recursively import elements and apply projection to the newly
/// imported objects.
///
/// If ext_list is not 0 the new element is also added to the list.
/// This simplifies construction of complex views where projected
/// elements are distributed into several scenes for optimization of
/// updates and rendering.
///
/// Returns the projected replica of el. Can be 0, if el and none of
/// its children are projectable.
 
REveElement* REveProjectionManager::ImportElements(REveElement* el,
                                                   REveElement* ext_list)
{
   WarnIfFrameDiffers(this, ext_list ? ext_list : this);
   REveElement* new_el = ImportElementsRecurse(el, ext_list ? ext_list : this);
   if (new_el)
   {
      AssertBBox();
      ProjectChildrenRecurse(new_el);
      AssertBBoxExtents(0.1);
 
      UpdateDependentElements(new_el);
 
      if (ext_list)
         AddNiece(new_el);
   }
   return new_el;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Recursively import elements and apply projection to the newly
/// imported objects.
///
/// The proj_parent argument should be a projected replica of parent
/// of element 'el'. This allows to insert projected children of
/// a given element when they are added after the projection has
/// been already performed on the parent.
/// This is called from REveElement::ProjectChild().
///
/// Returns the projected replica of el. Can be 0, if el and none of
/// its children are projectable.
 
REveElement* REveProjectionManager::SubImportElements(REveElement* el,
                                                      REveElement* proj_parent)
{
   WarnIfFrameDiffers(this, proj_parent);
   REveElement* new_el = ImportElementsRecurse(el, proj_parent);
   if (new_el)
   {
      AssertBBox();
      ProjectChildrenRecurse(new_el);
      AssertBBoxExtents(0.1);
 
      UpdateDependentElements(new_el);
   }
   return new_el;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Recursively import children elements of el and apply projection
/// to the newly imported objects.
///
/// The proj_parent argument should be a projected replica of
/// element 'el'. This allows to insert projected children of
/// a given element when they are added after the projection has
/// been already performed on the parent.
/// This is called from REveElement::ProjectChild().
///
/// Returns the projected replica of el. Can be 0, if el and none of
/// its children are projectable.
 
Int_t REveProjectionManager::SubImportChildren(REveElement* el, REveElement* proj_parent)
{
   WarnIfFrameDiffers(this, proj_parent);
   List_t new_els;
   for (auto &c: el->RefChildren()) {
      auto new_el = ImportElementsRecurse(c, proj_parent);
      if (new_el)
         new_els.push_back(new_el);
   }
 
   if (!new_els.empty())
   {
      AssertBBox();
      for (auto &nel: new_els)
         ProjectChildrenRecurse(nel);
      AssertBBoxExtents(0.1);
 
      UpdateDependentElements(proj_parent);
   }
   return (Int_t) new_els.size();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Project el (via REveProjected::UpdateProjection()) and recurse
/// through el's children.
/// Bounding-box is updated along the recursion.
 
void REveProjectionManager::ProjectChildrenRecurse(REveElement* el)
{
   REveProjected* pted = dynamic_cast<REveProjected*>(el);
   if (pted)
   {
      pted->UpdateProjection();
      el->StampObjProps();
      if (el->AssertBBox() == kBBoxSet) {
         BBoxCheckPoint(el->GetBBoxMin());
         BBoxCheckPoint(el->GetBBoxMax());
      }
   }
 
   for (auto &c : el->RefChildren())  ProjectChildrenRecurse(c);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Project all children recursively, update bounding-box and notify
/// EveManger about the scenes that have been changed.
 
void REveProjectionManager::ProjectChildren()
{
   BBoxInit();
 
   for (auto &c : fChildren)  ProjectChildrenRecurse(c);
 
   for (auto &n : fNieces)    ProjectChildrenRecurse(n);
 
   AssertBBoxExtents(0.1);
 
   UpdateDependentElements(this);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return the matrix that takes the coordinates of `model` into the frame of
/// this manager, in which the projection is computed:
/// inverse(W(this)) * W(model), with W(x) from x->ComposeSceneTrans(), as the
/// client composes them for the 3D view. When the two chains do not meet, their
/// tops are taken to be in the same frame.
///
/// Returns nullptr when neither chain has a matrix, and the model's own matrix
/// when it is the only one. Otherwise fills `t` and returns it, so `t` must
/// outlive the result.
 
const REveTrans *REveProjectionManager::GetModelTrans(REveElement *model, REveTrans &t)
{
   REveTrans wm;
   const int nm = ComposeSceneTrans(wm);
   const int n = model->ComposeSceneTrans(t);
 
   if (nm == 0) {
      if (n == 0)
         return nullptr;
      if (n == 1 && model->PtrMainTrans(kFALSE))
         return model->PtrMainTrans(kFALSE);
      return &t;
   }
 
   wm.Invert();
   if (n == 0)
      t = wm;
   else
      t.MultLeft(wm);
   return &t;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Fill the bounding box (virtual from REveElement) with the union of the
/// boxes of the projected elements below the children and the nieces.
/// ImportElements() and ProjectChildren() also widen it as they project.
 
void REveProjectionManager::ComputeBBox()
{
   if ( ! HasChildren() && ! HasNieces())
   {
      BBoxZero();
      return;
   }
 
   BBoxInit();
 
   std::function<void(REveElement *)> add = [&](REveElement *el) {
      if (dynamic_cast<REveProjected *>(el) && el->AssertBBox() == kBBoxSet &&
          el->GetBBoxMin().fX <= el->GetBBoxMax().fX) {
         BBoxCheckPoint(el->GetBBoxMin());
         BBoxCheckPoint(el->GetBBoxMax());
      }
      for (auto &c : el->RefChildren())
         add(c);
   };
   for (auto &c : fChildren)
      add(c);
   for (auto &n : fNieces)
      add(n);
 
   AssertBBoxExtents(0.1);
}