MovieSceneCompilerRules.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Compilation/MovieSceneSegmentCompiler.h"
#include "CoreMinimal.h"
#include "Misc/Optional.h"
 
struct FFrameNumber;
struct FMovieSceneSegment;
template <typename ElementType> class TRange;
 
namespace MovieSceneSegmentCompiler
{
    MOVIESCENE_API TOptional<FMovieSceneSegment> EvaluateNearestSegment(const TRange<FFrameNumber>& Range, const FMovieSceneSegment* PreviousSegment, const FMovieSceneSegment* NextSegment);
 
    MOVIESCENE_API bool AlwaysEvaluateSection(const FMovieSceneSectionData& InSectionData);
 
    MOVIESCENE_API void FilterOutUnderlappingSections(FSegmentBlendData& BlendData);
 
    MOVIESCENE_API void ChooseLowestRowIndex(FSegmentBlendData& BlendData);
 
    // Reduces the evaluated sections to only the section that resides last in the source data. Legacy behaviour from various track instances.
    MOVIESCENE_API void BlendSegmentLegacySectionOrder(FSegmentBlendData& BlendData);
}
 
struct FDefaultTrackRowSegmentBlender : FMovieSceneTrackRowSegmentBlender
{
    virtual void Blend(FSegmentBlendData& BlendData) const override
    {
        // By default we only evaluate the section with the highest Z-Order if they overlap on the same row
        MovieSceneSegmentCompiler::FilterOutUnderlappingSections(BlendData);
    }
};
 
struct FEvaluateNearestSegmentBlender : FMovieSceneTrackSegmentBlender
{
    FEvaluateNearestSegmentBlender()
    {
        bCanFillEmptySpace = true;
    }
 
    virtual TOptional<FMovieSceneSegment> InsertEmptySpace(const TRange<FFrameNumber>& Range, const FMovieSceneSegment* PreviousSegment, const FMovieSceneSegment* NextSegment) const
    {
        return MovieSceneSegmentCompiler::EvaluateNearestSegment(Range, PreviousSegment, NextSegment);
    }
};
 
struct FMovieSceneAdditiveCameraTrackBlender : public FMovieSceneTrackSegmentBlender
{
    virtual void Blend(FSegmentBlendData& BlendData) const override
    {
        // sort by start time to match application order of player camera
        BlendData.Sort(SortByStartTime);
    }
 
private:
 
    MOVIESCENE_API static bool SortByStartTime(const FMovieSceneSectionData& A, const FMovieSceneSectionData& B);
};