HeightFieldShape.h

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// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
// SPDX-License-Identifier: MIT
 
#pragma once
 
#include <Jolt/Physics/Collision/Shape/Shape.h>
#include <Jolt/Physics/Collision/PhysicsMaterial.h>
#ifdef JPH_DEBUG_RENDERER
    #include <Jolt/Renderer/DebugRenderer.h>
#endif // JPH_DEBUG_RENDERER
 
JPH_NAMESPACE_BEGIN
 
class ConvexShape;
class CollideShapeSettings;
 
namespace HeightFieldShapeConstants
{
    constexpr float         cNoCollisionValue = FLT_MAX;
 
    constexpr int           cStackSize = 128;
 
    constexpr uint          cNumBitsXY = 14;
    constexpr uint          cMaskBitsXY = (1 << cNumBitsXY) - 1;
    constexpr uint          cLevelShift = 2 * cNumBitsXY;
 
    constexpr uint16        cNoCollisionValue16 = 0xffff;       
    constexpr uint16        cMaxHeightValue16 = 0xfffe;         
};
 
class HeightFieldShapeSettings final : public ShapeSettings
{
public:
    JPH_DECLARE_SERIALIZABLE_VIRTUAL(HeightFieldShapeSettings)
 
    
                                    HeightFieldShapeSettings() = default;
 
                                    HeightFieldShapeSettings(const float *inSamples, Vec3Arg inOffset, Vec3Arg inScale, uint32 inSampleCount, const uint8 *inMaterialIndices = nullptr, const PhysicsMaterialList &inMaterialList = PhysicsMaterialList());
 
    // See: ShapeSettings
    virtual ShapeResult             Create() const override;
 
    void                            DetermineMinAndMaxSample(float &outMinValue, float &outMaxValue, float &outQuantizationScale) const;
 
    uint32                          CalculateBitsPerSampleForError(float inMaxError) const;
 
    Vec3                            mOffset = Vec3::sZero();
    Vec3                            mScale = Vec3::sReplicate(1.0f);
    uint32                          mSampleCount = 0;
 
    uint32                          mBlockSize = 2;
 
    uint32                          mBitsPerSample = 8;
 
    Array<float>                    mHeightSamples;
    Array<uint8>                    mMaterialIndices;
 
    PhysicsMaterialList             mMaterials;
};
 
class HeightFieldShape final : public Shape
{
public:
    JPH_OVERRIDE_NEW_DELETE
 
                                    HeightFieldShape() : Shape(EShapeType::HeightField, EShapeSubType::HeightField) { }
                                    HeightFieldShape(const HeightFieldShapeSettings &inSettings, ShapeResult &outResult);
 
    // See Shape::MustBeStatic
    virtual bool                    MustBeStatic() const override                                       { return true; }
 
    // See Shape::GetLocalBounds
    virtual AABox                   GetLocalBounds() const override;
 
    // See Shape::GetSubShapeIDBitsRecursive
    virtual uint                    GetSubShapeIDBitsRecursive() const override                         { return GetSubShapeIDBits(); }
 
    // See Shape::GetInnerRadius
    virtual float                   GetInnerRadius() const override                                     { return 0.0f; }
 
    // See Shape::GetMassProperties
    virtual MassProperties          GetMassProperties() const override;
    
    // See Shape::GetMaterial
    virtual const PhysicsMaterial * GetMaterial(const SubShapeID &inSubShapeID) const override;
 
    const PhysicsMaterial *         GetMaterial(uint inX, uint inY) const;
 
    // See Shape::GetSurfaceNormal
    virtual Vec3                    GetSurfaceNormal(const SubShapeID &inSubShapeID, Vec3Arg inLocalSurfacePosition) const override;
 
    // See Shape::GetSupportingFace
    virtual void                    GetSupportingFace(const SubShapeID &inSubShapeID, Vec3Arg inDirection, Vec3Arg inScale, Mat44Arg inCenterOfMassTransform, SupportingFace &outVertices) const override;
 
    // See Shape::GetSubmergedVolume
    virtual void                    GetSubmergedVolume(Mat44Arg inCenterOfMassTransform, Vec3Arg inScale, const Plane &inSurface, float &outTotalVolume, float &outSubmergedVolume, Vec3 &outCenterOfBuoyancy JPH_IF_DEBUG_RENDERER(, RVec3Arg inBaseOffset)) const override { JPH_ASSERT(false, "Not supported"); }
 
#ifdef JPH_DEBUG_RENDERER
    // See Shape::Draw
    virtual void                    Draw(DebugRenderer *inRenderer, RMat44Arg inCenterOfMassTransform, Vec3Arg inScale, ColorArg inColor, bool inUseMaterialColors, bool inDrawWireframe) const override;
#endif // JPH_DEBUG_RENDERER
 
    // See Shape::CastRay
    virtual bool                    CastRay(const RayCast &inRay, const SubShapeIDCreator &inSubShapeIDCreator, RayCastResult &ioHit) const override;
    virtual void                    CastRay(const RayCast &inRay, const RayCastSettings &inRayCastSettings, const SubShapeIDCreator &inSubShapeIDCreator, CastRayCollector &ioCollector, const ShapeFilter &inShapeFilter = { }) const override;
 
    // See: Shape::CollidePoint
    virtual void                    CollidePoint(Vec3Arg inPoint, const SubShapeIDCreator &inSubShapeIDCreator, CollidePointCollector &ioCollector, const ShapeFilter &inShapeFilter = { }) const override;
 
    // See Shape::GetTrianglesStart
    virtual void                    GetTrianglesStart(GetTrianglesContext &ioContext, const AABox &inBox, Vec3Arg inPositionCOM, QuatArg inRotation, Vec3Arg inScale) const override;
 
    // See Shape::GetTrianglesNext
    virtual int                     GetTrianglesNext(GetTrianglesContext &ioContext, int inMaxTrianglesRequested, Float3 *outTriangleVertices, const PhysicsMaterial **outMaterials = nullptr) const override;
 
    Vec3                            GetPosition(uint inX, uint inY) const;
 
    bool                            IsNoCollision(uint inX, uint inY) const;
 
    bool                            ProjectOntoSurface(Vec3Arg inLocalPosition, Vec3 &outSurfacePosition, SubShapeID &outSubShapeID) const;
 
    // See Shape
    virtual void                    SaveBinaryState(StreamOut &inStream) const override;
    virtual void                    SaveMaterialState(PhysicsMaterialList &outMaterials) const override;
    virtual void                    RestoreMaterialState(const PhysicsMaterialRefC *inMaterials, uint inNumMaterials) override;
 
    // See Shape::GetStats
    virtual Stats                   GetStats() const override;
 
    // See Shape::GetVolume
    virtual float                   GetVolume() const override                                          { return 0; }
 
#ifdef JPH_DEBUG_RENDERER
    // Settings
    static bool                     sDrawTriangleOutlines;
#endif // JPH_DEBUG_RENDERER
 
    // Register shape functions with the registry
    static void                     sRegister();
 
protected:
    // See: Shape::RestoreBinaryState
    virtual void                    RestoreBinaryState(StreamIn &inStream) override;
 
private:    
    class                           DecodingContext;                        
    struct                          HSGetTrianglesContext;                  
 
    void                            CacheValues();
 
    void                            CalculateActiveEdges();
    
    void                            StoreMaterialIndices(const Array<uint8> &inMaterialIndices);
 
    inline uint                     GetNumBlocks() const                    { return mSampleCount / mBlockSize; }
 
    static inline uint              sGetMaxLevel(uint inNumBlocks)          { return CountTrailingZeros(inNumBlocks); }
    
    static inline void              sGetRangeBlockOffsetAndStride(uint inNumBlocks, uint inMaxLevel, uint &outRangeBlockOffset, uint &outRangeBlockStride);
 
    inline void                     GetBlockOffsetAndScale(uint inBlockX, uint inBlockY, uint inRangeBlockOffset, uint inRangeBlockStride, float &outBlockOffset, float &outBlockScale) const;
 
    inline uint8                    GetHeightSample(uint inX, uint inY) const;
 
    inline Vec3                     GetPosition(uint inX, uint inY, float inBlockOffset, float inBlockScale, bool &outNoCollision) const;
        
    uint                            GetSubShapeIDBits() const;
 
    inline SubShapeID               EncodeSubShapeID(const SubShapeIDCreator &inCreator, uint inX, uint inY, uint inTriangle) const;
    inline void                     DecodeSubShapeID(const SubShapeID &inSubShapeID, uint &outX, uint &outY, uint &outTriangle) const;
 
    inline uint8                    GetEdgeFlags(uint inX, uint inY, uint inTriangle) const;
 
    // Helper functions called by CollisionDispatch
    static void                     sCollideConvexVsHeightField(const Shape *inShape1, const Shape *inShape2, Vec3Arg inScale1, Vec3Arg inScale2, Mat44Arg inCenterOfMassTransform1, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, const CollideShapeSettings &inCollideShapeSettings, CollideShapeCollector &ioCollector, const ShapeFilter &inShapeFilter);
    static void                     sCollideSphereVsHeightField(const Shape *inShape1, const Shape *inShape2, Vec3Arg inScale1, Vec3Arg inScale2, Mat44Arg inCenterOfMassTransform1, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, const CollideShapeSettings &inCollideShapeSettings, CollideShapeCollector &ioCollector, const ShapeFilter &inShapeFilter);
    static void                     sCastConvexVsHeightField(const ShapeCast &inShapeCast, const ShapeCastSettings &inShapeCastSettings, const Shape *inShape, Vec3Arg inScale, const ShapeFilter &inShapeFilter, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, CastShapeCollector &ioCollector);
    static void                     sCastSphereVsHeightField(const ShapeCast &inShapeCast, const ShapeCastSettings &inShapeCastSettings, const Shape *inShape, Vec3Arg inScale, const ShapeFilter &inShapeFilter, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, CastShapeCollector &ioCollector);
 
    template <class Visitor>
    JPH_INLINE void                 WalkHeightField(Visitor &ioVisitor) const;
 
    struct alignas(16) RangeBlock
    {
        uint16                      mMin[4];
        uint16                      mMax[4];
    };
 
    static const uint               sGridOffsets[];
 
    Vec3                            mOffset = Vec3::sZero();
    Vec3                            mScale = Vec3::sReplicate(1.0f);
 
    uint32                          mSampleCount = 0;                   
    uint32                          mBlockSize = 2;                     
    uint8                           mBitsPerSample = 8;                 
    uint8                           mSampleMask = 0xff;                 
    uint16                          mMinSample = HeightFieldShapeConstants::cNoCollisionValue16;    
    uint16                          mMaxSample = HeightFieldShapeConstants::cNoCollisionValue16;
    Array<RangeBlock>               mRangeBlocks;                       
    Array<uint8>                    mHeightSamples;                     
    Array<uint8>                    mActiveEdges;                       
 
    PhysicsMaterialList             mMaterials;                         
    Array<uint8>                    mMaterialIndices;                   
    uint32                          mNumBitsPerMaterialIndex = 0;       
 
#ifdef JPH_DEBUG_RENDERER
    mutable Array<DebugRenderer::GeometryRef> mGeometry;
    mutable bool                    mCachedUseMaterialColors = false;   
#endif // JPH_DEBUG_RENDERER
};
 
JPH_NAMESPACE_END