CompoundShape.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/Shape/ScaleHelpers.h>
#include <Jolt/Physics/Collision/Shape/SubShapeID.h>
 
JPH_NAMESPACE_BEGIN
 
class CollideShapeSettings;
class OrientedBox;

class JPH_EXPORT CompoundShapeSettings : public ShapeSettings
{
    JPH_DECLARE_SERIALIZABLE_ABSTRACT(JPH_EXPORT, CompoundShapeSettings)
 
public:
                                    CompoundShapeSettings() = default;

    void                            AddShape(Vec3Arg inPosition, QuatArg inRotation, const ShapeSettings *inShape, uint32 inUserData = 0);

    void                            AddShape(Vec3Arg inPosition, QuatArg inRotation, const Shape *inShape, uint32 inUserData = 0);
 
    struct SubShapeSettings
    {
        JPH_DECLARE_SERIALIZABLE_NON_VIRTUAL(JPH_EXPORT, SubShapeSettings)
 
        RefConst<ShapeSettings>     mShape;                                                 
        RefConst<Shape>             mShapePtr;                                              
        Vec3                        mPosition;                                              
        Quat                        mRotation;                                              

        uint32                      mUserData = 0;
    };
 
    using SubShapes = Array<SubShapeSettings>;
 
    SubShapes                       mSubShapes;
};

class JPH_EXPORT CompoundShape : public Shape
{
public:
    JPH_OVERRIDE_NEW_DELETE

    explicit                        CompoundShape(EShapeSubType inSubType) : Shape(EShapeType::Compound, inSubType) { }
                                    CompoundShape(EShapeSubType inSubType, const ShapeSettings &inSettings, ShapeResult &outResult) : Shape(EShapeType::Compound, inSubType, inSettings, outResult) { }
 
    // See Shape::GetCenterOfMass
    virtual Vec3                    GetCenterOfMass() const override                        { return mCenterOfMass; }
 
    // See Shape::MustBeStatic
    virtual bool                    MustBeStatic() const override;
 
    // See Shape::GetLocalBounds
    virtual AABox                   GetLocalBounds() const override                         { return mLocalBounds; }
 
    // See Shape::GetSubShapeIDBitsRecursive
    virtual uint                    GetSubShapeIDBitsRecursive() const override;
 
    // See Shape::GetWorldSpaceBounds
    virtual AABox                   GetWorldSpaceBounds(Mat44Arg inCenterOfMassTransform, Vec3Arg inScale) const override;
    using Shape::GetWorldSpaceBounds;
 
    // See Shape::GetInnerRadius
    virtual float                   GetInnerRadius() const override                         { return mInnerRadius; }
 
    // See Shape::GetMassProperties
    virtual MassProperties          GetMassProperties() const override;
 
    // See Shape::GetMaterial
    virtual const PhysicsMaterial * GetMaterial(const SubShapeID &inSubShapeID) const override;
 
    // See Shape::GetLeafShape
    virtual const Shape *           GetLeafShape(const SubShapeID &inSubShapeID, SubShapeID &outRemainder) const override;
 
    // See Shape::GetSubShapeUserData
    virtual uint64                  GetSubShapeUserData(const SubShapeID &inSubShapeID) const override;
 
    // See Shape::GetSubShapeTransformedShape
    virtual TransformedShape        GetSubShapeTransformedShape(const SubShapeID &inSubShapeID, Vec3Arg inPositionCOM, QuatArg inRotation, Vec3Arg inScale, SubShapeID &outRemainder) const override;
 
    // 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;
 
#ifdef JPH_DEBUG_RENDERER
    // See Shape::Draw
    virtual void                    Draw(DebugRenderer *inRenderer, RMat44Arg inCenterOfMassTransform, Vec3Arg inScale, ColorArg inColor, bool inUseMaterialColors, bool inDrawWireframe) const override;
 
    // See Shape::DrawGetSupportFunction
    virtual void                    DrawGetSupportFunction(DebugRenderer *inRenderer, RMat44Arg inCenterOfMassTransform, Vec3Arg inScale, ColorArg inColor, bool inDrawSupportDirection) const override;
 
    // See Shape::DrawGetSupportingFace
    virtual void                    DrawGetSupportingFace(DebugRenderer *inRenderer, RMat44Arg inCenterOfMassTransform, Vec3Arg inScale) const override;
#endif // JPH_DEBUG_RENDERER
 
    // See: Shape::CollideSoftBodyVertices
    virtual void                    CollideSoftBodyVertices(Mat44Arg inCenterOfMassTransform, Vec3Arg inScale, const CollideSoftBodyVertexIterator &inVertices, uint inNumVertices, int inCollidingShapeIndex) const override;
 
    // See Shape::TransformShape
    virtual void                    TransformShape(Mat44Arg inCenterOfMassTransform, TransformedShapeCollector &ioCollector) const override;
 
    // See Shape::GetTrianglesStart
    virtual void                    GetTrianglesStart(GetTrianglesContext &ioContext, const AABox &inBox, Vec3Arg inPositionCOM, QuatArg inRotation, Vec3Arg inScale) const override { JPH_ASSERT(false, "Cannot call on non-leaf shapes, use CollectTransformedShapes to collect the leaves first!"); }
 
    // See Shape::GetTrianglesNext
    virtual int                     GetTrianglesNext(GetTrianglesContext &ioContext, int inMaxTrianglesRequested, Float3 *outTriangleVertices, const PhysicsMaterial **outMaterials = nullptr) const override { JPH_ASSERT(false, "Cannot call on non-leaf shapes, use CollectTransformedShapes to collect the leaves first!"); return 0; }

    virtual int                     GetIntersectingSubShapes(const AABox &inBox, uint *outSubShapeIndices, int inMaxSubShapeIndices) const = 0;

    virtual int                     GetIntersectingSubShapes(const OrientedBox &inBox, uint *outSubShapeIndices, int inMaxSubShapeIndices) const = 0;
 
    struct SubShape
    {
        bool                        FromSettings(const CompoundShapeSettings::SubShapeSettings &inSettings, ShapeResult &outResult)
        {
            if (inSettings.mShapePtr != nullptr)
            {
                // Use provided shape
                mShape = inSettings.mShapePtr;
            }
            else
            {
                // Create child shape
                ShapeResult child_result = inSettings.mShape->Create();
                if (!child_result.IsValid())
                {
                    outResult = child_result;
                    return false;
                }
                mShape = child_result.Get();
            }
 
            // Copy user data
            mUserData = inSettings.mUserData;
 
            SetTransform(inSettings.mPosition, inSettings.mRotation, Vec3::sZero() /* Center of mass not yet calculated */);
            return true;
        }

        JPH_INLINE void             SetTransform(Vec3Arg inPosition, QuatArg inRotation, Vec3Arg inCenterOfMass)
        {
            SetPositionCOM(inPosition - inCenterOfMass + inRotation * mShape->GetCenterOfMass());
 
            mIsRotationIdentity = inRotation.IsClose(Quat::sIdentity()) || inRotation.IsClose(-Quat::sIdentity());
            SetRotation(mIsRotationIdentity? Quat::sIdentity() : inRotation);
        }

        JPH_INLINE Mat44            GetLocalTransformNoScale(Vec3Arg inScale) const
        {
            JPH_ASSERT(IsValidScale(inScale));
            return Mat44::sRotationTranslation(GetRotation(), inScale * GetPositionCOM());
        }

        inline bool                 IsValidScale(Vec3Arg inScale) const
        {
            // We can always handle uniform scale or identity rotations
            if (mIsRotationIdentity || ScaleHelpers::IsUniformScale(inScale))
                return true;
 
            return ScaleHelpers::CanScaleBeRotated(GetRotation(), inScale);
        }

        inline Vec3                 TransformScale(Vec3Arg inScale) const
        {
            // We don't need to transform uniform scale or if the rotation is identity
            if (mIsRotationIdentity || ScaleHelpers::IsUniformScale(inScale))
                return inScale;
 
            return ScaleHelpers::RotateScale(GetRotation(), inScale);
        }

        JPH_INLINE void             SetPositionCOM(Vec3Arg inPositionCOM)
        {
            inPositionCOM.StoreFloat3(&mPositionCOM);
        }

        JPH_INLINE Vec3             GetPositionCOM() const
        {
            return Vec3::sLoadFloat3Unsafe(mPositionCOM);
        }

        JPH_INLINE void             SetRotation(QuatArg inRotation)
        {
            inRotation.StoreFloat3(&mRotation);
        }

        JPH_INLINE Quat             GetRotation() const
        {
            return mIsRotationIdentity? Quat::sIdentity() : Quat::sLoadFloat3Unsafe(mRotation);
        }
 
        RefConst<Shape>             mShape;
        Float3                      mPositionCOM;                                           
        Float3                      mRotation;                                              
        uint32                      mUserData;                                              
        bool                        mIsRotationIdentity;                                    
        // 3 padding bytes left
    };
 
    static_assert(sizeof(SubShape) == (sizeof(void *) == 8? 40 : 36), "Compiler added unexpected padding");
 
    using SubShapes = Array<SubShape>;

    const SubShapes &               GetSubShapes() const                                    { return mSubShapes; }

    uint                            GetNumSubShapes() const                                 { return uint(mSubShapes.size()); }

    const SubShape &                GetSubShape(uint inIdx) const                           { return mSubShapes[inIdx]; }

    uint32                          GetCompoundUserData(uint inIdx) const                   { return mSubShapes[inIdx].mUserData; }

    void                            SetCompoundUserData(uint inIdx, uint32 inUserData)      { mSubShapes[inIdx].mUserData = inUserData; }

    inline bool                     IsSubShapeIDValid(SubShapeID inSubShapeID) const
    {
        SubShapeID remainder;
        return inSubShapeID.PopID(GetSubShapeIDBits(), remainder) < mSubShapes.size();
    }

    inline uint32                   GetSubShapeIndexFromID(SubShapeID inSubShapeID, SubShapeID &outRemainder) const
    {
        uint32 idx = inSubShapeID.PopID(GetSubShapeIDBits(), outRemainder);
        JPH_ASSERT(idx < mSubShapes.size(), "Invalid SubShapeID");
        return idx;
    }

    inline SubShapeIDCreator        GetSubShapeIDFromIndex(int inIdx, const SubShapeIDCreator &inParentSubShapeID) const
    {
        return inParentSubShapeID.PushID(inIdx, GetSubShapeIDBits());
    }
 
    // See Shape
    virtual void                    SaveBinaryState(StreamOut &inStream) const override;
    virtual void                    SaveSubShapeState(ShapeList &outSubShapes) const override;
    virtual void                    RestoreSubShapeState(const ShapeRefC *inSubShapes, uint inNumShapes) override;
 
    // See Shape::GetStatsRecursive
    virtual Stats                   GetStatsRecursive(VisitedShapes &ioVisitedShapes) const override;
 
    // See Shape::GetVolume
    virtual float                   GetVolume() const override;
 
    // See Shape::IsValidScale
    virtual bool                    IsValidScale(Vec3Arg inScale) const override;
 
    // See Shape::MakeScaleValid
    virtual Vec3                    MakeScaleValid(Vec3Arg inScale) const override;
 
    // Register shape functions with the registry
    static void                     sRegister();
 
protected:
    // See: Shape::RestoreBinaryState
    virtual void                    RestoreBinaryState(StreamIn &inStream) override;
 
    // Visitors for collision detection
    struct CastRayVisitor;
    struct CastRayVisitorCollector;
    struct CollidePointVisitor;
    struct CastShapeVisitor;
    struct CollectTransformedShapesVisitor;
    struct CollideCompoundVsShapeVisitor;
    struct CollideShapeVsCompoundVisitor;
    template <class BoxType> struct GetIntersectingSubShapesVisitor;

    inline uint                     GetSubShapeIDBits() const
    {
        // Ensure we have enough bits to encode our shape [0, n - 1]
        uint32 n = uint32(mSubShapes.size()) - 1;
        return 32 - CountLeadingZeros(n);
    }

    inline void                     CalculateInnerRadius()
    {
        mInnerRadius = FLT_MAX;
        for (const SubShape &s : mSubShapes)
            mInnerRadius = min(mInnerRadius, s.mShape->GetInnerRadius());
    }
 
    Vec3                            mCenterOfMass { Vec3::sZero() };                        
    AABox                           mLocalBounds { Vec3::sZero(), Vec3::sZero() };
    SubShapes                       mSubShapes;
    float                           mInnerRadius = FLT_MAX;                                 
 
private:
    // Helper functions called by CollisionDispatch
    static void                     sCastCompoundVsShape(const ShapeCast &inShapeCast, const ShapeCastSettings &inShapeCastSettings, const Shape *inShape, Vec3Arg inScale, const ShapeFilter &inShapeFilter, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, CastShapeCollector &ioCollector);
};
 
JPH_NAMESPACE_END