MovieSceneSequenceVisitor.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
#include "Evaluation/MovieSceneSequenceTransform.h"
#include "HAL/Platform.h"
#include "Math/Range.h"
#include "Misc/FrameNumber.h"
#include "MovieSceneSequenceID.h"
 
class UMovieSceneSection;
class UMovieSceneSequence;
class UMovieSceneSubSection;
class UMovieSceneTrack;
struct FGuid;
struct FMovieSceneBinding;
 
/*
* Implements a visitor pattern to allow external code to easily iterate through a sequence hierarchy,
* running custom code for each track, object, sub-section, or section visited. This handles skipping 
* over non-evaluated sub-scenes as well as accumulation of clamp ranges and sequence transforms as
* it iterates through the hierarchy. This does not currently support looping (only visits once, though
* FSubSequenceSpace::LocalClampRange will be the range of all the loops).
*
* Example:
*
*   using FCameraCutInfo = TTuple<UMovieSceneCameraCutSection*, FMovieSceneSequenceID, int16>;
*   struct FCameraCutVisitor : UE::MovieScene::ISequenceVisitor
*   {
*       virtual void VisitTrack(UMovieSceneTrack* InTrack, const FGuid&, const UE::MovieScene::FSubSequenceSpace& LocalSpace)
*       {
*           if (UMovieSceneCameraCutTrack* CameraCutTrack = Cast<UMovieSceneCameraCutTrack>(InTrack))
*           {
*               for (UMovieSceneSection* Section : CameraCutTrack->GetAllSections())
*               {
*                   if (!Section->IsActive())
*                   {
*                       continue;
*                   }
*   
*                   UMovieSceneCameraCutSection* CameraCutSection = CastChecked<UMovieSceneCameraCutSection>(Section);
*                   TRange<FFrameNumber> RootCameraRange = TRange<FFrameNumber>::Intersection(LocalSpace.RootClampRange, CameraCutSection->GetRange() * LocalSpace.RootToSequenceTransform.InverseNoLooping());
*                   if (!RootCameraRange.IsEmpty())
*                   {
*                       CameraCutTree.Add(RootCameraRange, MakeTuple(CameraCutSection, LocalSpace.SequenceID, LocalSpace.HierarchicalBias));
*                   }
*               }
*           }
*       }
*       TMovieSceneEvaluationTree<FCameraCutInfo> CameraCutTree;
*   };
*   
*   UE::MovieScene::FSequenceVisitParams Params;
*   Params.bVisitRootTracks = true;
*   Params.bVisitSubSequences = true;
*   FCameraCutVisitor CameraCutVisitor;
*   
*   // Visit all camera cuts
*   VisitSequence(InSequence, Params, CameraCutVisitor);
*/
 
 
namespace UE
{
namespace MovieScene
{
 
struct FSubSequenceSpace
{
    MOVIESCENE_API FSubSequenceSpace();
 
    FMovieSceneSequenceTransform RootToSequenceTransform;
#if WITH_EDITORONLY_DATA
    FMovieSceneSequenceTransform RootToUnwarpedLocalTransform;
#endif
    FMovieSceneTransformBreadcrumbs StartBreadcrumbs;
    FMovieSceneTransformBreadcrumbs EndBreadcrumbs;
    FMovieSceneSequenceID SequenceID;
    TRange<FFrameNumber> RootClampRange;
    TRange<FFrameNumber> LocalClampRange;
    int16 HierarchicalBias;
};
 
struct ISequenceVisitor
{
    virtual ~ISequenceVisitor() {}
 
    virtual void VisitObjectBinding(const FMovieSceneBinding&, const FSubSequenceSpace& LocalSpace) {}
 
    virtual void VisitTrack(UMovieSceneTrack*, const FGuid&, const FSubSequenceSpace& LocalSpace) {}
 
    virtual void VisitSection(UMovieSceneTrack*, UMovieSceneSection*, const FGuid&, const FSubSequenceSpace& LocalSpace) {}
 
    virtual void VisitSubSequence(UMovieSceneSequence*, const FGuid&, const FSubSequenceSpace& LocalSpace) {}
 
    virtual void VisitStartSubSequence(UMovieSceneSubSection*, const FGuid&, const FSubSequenceSpace& LocalSpace) {}
    virtual void VisitEndSubSequence(UMovieSceneSubSection*, const FGuid&, const FSubSequenceSpace& LocalSpace) {}
};
 
struct FSequenceVisitParams
{
    FSequenceVisitParams()
        : bVisitRootTracks(false)
        , bVisitObjectBindings(false)
        , bVisitTracks(false)
        , bVisitSections(false)
        , bVisitDisabledSections(false)
        , bVisitSubSequences(false)
        , bVisitDisabledSubSequences(false)
    {}
 
    bool CanVisitTracksOrSections() const
    {
        return bVisitTracks || bVisitSections;
    }
 
    bool bVisitRootTracks;
    bool bVisitObjectBindings;
    bool bVisitTracks;
    bool bVisitSections;
    bool bVisitDisabledSections;
    bool bVisitSubSequences;
    bool bVisitDisabledSubSequences;
};
 
 
MOVIESCENE_API void VisitSequence(UMovieSceneSequence* Sequence, const FSequenceVisitParams& InParams, ISequenceVisitor& Visitor);
 
 
} // namespace MovieScene
} // namespace UE