StairGenerator.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "Containers/Array.h"
#include "Generators/MeshShapeGenerator.h"
#include "IndexTypes.h"
#include "Math/MathFwd.h"
#include "Math/Vector.h"
#include "Math/Vector2D.h"
 
 
namespace UE
{
namespace Geometry
{
 
 
class FStairGenerator : public FMeshShapeGenerator
{
public:
    bool bScaleUVByAspectRatio = true;
 
    bool bPolygroupPerQuad = false;
 
    float StepWidth = 150.0f;
 
    float StepHeight = 20.0f;
 
    int NumSteps = 8;
 
    enum class ESide
    {
        Right,  // +Y
        Left,   // -Y
        Front,  // -X
        Top,    // +Z
        Back,   // +X
        Bottom  // -Z
    };
 
public:
    GEOMETRYCORE_API virtual ~FStairGenerator() override;
 
    GEOMETRYCORE_API virtual FMeshShapeGenerator& Generate() override;
 
private:
    GEOMETRYCORE_API FMeshShapeGenerator& GenerateSolidStairs();
 
    GEOMETRYCORE_API FMeshShapeGenerator& GenerateFloatingStairs();
 
    GEOMETRYCORE_API ESide FaceToSide(int FaceId);
 
protected:
    enum class EStairStyle
    {
        Solid,      // Each step is supported by the floor.
        Floating    // Each step only supported by previous step.
    };
    EStairStyle StairStyle = EStairStyle::Solid;
 
protected:
    TArray<TArray<int>> VertexIds;
    TArray<FIndex2i> VertexIdsToColumnRow;
    TArray<int> FaceDesc;
    TArray<int> NormalDesc;
    TArray<int> UVDesc;
 
    int NumQuadsPerSide = 0;
    int NumQuads = 0;
    int NumVertsPerSide = 0;
    int NumVerts = 0;
    int NumAttrs = 0;
    
    int RightSideColumnId = 0;
    int LeftSideColumnId = 0;
 
    int RightStartFaceId = 0;
    int LeftStartFaceId = 0;
    int FrontStartFaceId = 0;
    int TopStartFaceId = 0;
    int BackStartFaceId = 0;
    int BottomStartFaceId = 0;
    int LastFaceId = 0;
 
protected:
    GEOMETRYCORE_API virtual void ResetData();
 
    virtual FVector3d GenerateVertex(ESide Side, int VertexColumn, int VertexRow) = 0;
 
    virtual FVector3f GenerateNormal(ESide Side, int VertexId) = 0;
    
    virtual FVector2f GenerateUV(ESide Side, int Step, int VertexId, float UVScale) = 0;
 
    virtual float GetMaxDimension() = 0;
};
 
class FLinearStairGenerator : public FStairGenerator
{
public:
    float StepDepth = 30.0f;
 
public:
    FLinearStairGenerator()
    {
        StairStyle = EStairStyle::Solid;
    }
    virtual ~FLinearStairGenerator() override
    {
    }
 
protected:
    typedef FStairGenerator Super;
 
protected:
    GEOMETRYCORE_API virtual FVector3d GenerateVertex(ESide Side, int VertexColumn, int VertexRow) override;
    GEOMETRYCORE_API virtual FVector3f GenerateNormal(ESide Side, int VertexId) override;
    GEOMETRYCORE_API virtual FVector2f GenerateUV(ESide Side, int Step, int VertexId, float UVScale) override;
    GEOMETRYCORE_API virtual float GetMaxDimension() override;
};
 
class FFloatingStairGenerator : public FLinearStairGenerator
{
public:
    FFloatingStairGenerator()
    {
        StairStyle = EStairStyle::Floating;
    }
    virtual ~FFloatingStairGenerator() override
    {
    }
 
protected:
    typedef FLinearStairGenerator Super;
 
protected:
    GEOMETRYCORE_API virtual FVector3d GenerateVertex(ESide Side, int VertexColumn, int VertexRow) override;
    GEOMETRYCORE_API virtual FVector2f GenerateUV(ESide Side, int Step, int VertexId, float UVScale) override;
};
 
class FCurvedStairGenerator : public FStairGenerator
{
public:
    float InnerRadius = 150.0f;
 
    float CurveAngle = 90.0f;
 
public:
    FCurvedStairGenerator()
    {
        StairStyle = EStairStyle::Solid;
    }
    virtual ~FCurvedStairGenerator() override
    {
    }
 
protected:
    typedef FStairGenerator Super;
 
    bool bIsClockwise = true;
    float CurveRadians = 0.0f;
    float CurveRadiansPerStep = 0.0f;
    float OuterRadius = 0.0f;
    float RadiusRatio = 1.0f;
    FVector3f BackNormal = FVector3f::Zero();
 
protected:
    GEOMETRYCORE_API virtual void ResetData() override;
    GEOMETRYCORE_API virtual FVector3d GenerateVertex(ESide Side, int VertexColumn, int VertexRow) override;
    GEOMETRYCORE_API virtual FVector3f GenerateNormal(ESide Side, int VertexId) override;
    GEOMETRYCORE_API virtual FVector2f GenerateUV(ESide Side, int Step, int VertexId, float UVScale) override;
    GEOMETRYCORE_API virtual float GetMaxDimension() override;
};
 
 
class FSpiralStairGenerator : public FCurvedStairGenerator
{
public:
    FSpiralStairGenerator()
    {
        StairStyle = EStairStyle::Floating;
    }
    virtual ~FSpiralStairGenerator() override
    {
    }
 
protected:
    typedef FCurvedStairGenerator Super;
 
protected:
    GEOMETRYCORE_API virtual FVector3d GenerateVertex(ESide Side, int VertexColumn, int VertexRow) override;
    GEOMETRYCORE_API virtual FVector2f GenerateUV(ESide Side, int Step, int VertexId, float UVScale) override;
};
 
} // end namespace UE::Geometry
} // end namespace UE