TessellationTable.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
#include "CoreMinimal.h"
#include "Math/IntVector.h"
 
namespace Nanite
{
 
class FTessellationTable
{
public:
    static constexpr uint32 BarycentricMax = 1 << 15;
 
    TArray< FUintVector2 >  OffsetTable;
    TArray< uint32 >        VertsAndIndexes;
 
public:
                FTessellationTable();
     int32      GetPattern( FIntVector TessFactors ) const;
 
    uint32      GetNumVerts( int32 Pattern ) const;
    uint32      GetNumTris( int32 Pattern ) const;
 
private:
    FIntVector  GetBarycentrics( uint32 Vert ) const;
    void        SnapAtEdges( FIntVector& Barycentrics, const FIntVector& TessFactors ) const;
 
    void        AddPatch( const FIntVector& TessFactors );
    void        AddToVertsAndIndices( bool bImmediate, const FIntVector& TessFactors );
 
    void        ConstrainToCacheWindow();
    void        ConstrainForImmediateTessellation();
 
    void        WriteSVG( const FIntVector& TessFactors );
 
    TArray< uint32 >        Verts;
    TArray< uint32 >        Indexes;
};
 
inline uint32 FTessellationTable::GetNumVerts( int32 Pattern ) const
{
    return  OffsetTable[ Pattern + 1 ].X -
            OffsetTable[ Pattern ].X;
}
 
inline uint32 FTessellationTable::GetNumTris( int32 Pattern ) const
{
    return  OffsetTable[ Pattern + 1 ].Y -
            OffsetTable[ Pattern ].Y;
}
 
} // namespace Nanite