JoltPhysics/Jolt/Physics/Collision/Shape/OffsetCenterOfMassShape.h

// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
// SPDX-License-Identifier: MIT

#pragma once

#include <Jolt/Physics/Collision/Shape/DecoratedShape.h>

JPH_NAMESPACE_BEGIN

class CollideShapeSettings;

/// Class that constructs an OffsetCenterOfMassShape
class OffsetCenterOfMassShapeSettings final : public DecoratedShapeSettings
{
public:
	JPH_DECLARE_SERIALIZABLE_VIRTUAL(OffsetCenterOfMassShapeSettings)

	/// Constructor
									OffsetCenterOfMassShapeSettings() = default;

	/// Construct with shape settings, can be serialized.
									OffsetCenterOfMassShapeSettings(Vec3Arg inOffset, const ShapeSettings *inShape) : DecoratedShapeSettings(inShape), mOffset(inOffset) { }

	/// Variant that uses a concrete shape, which means this object cannot be serialized.
									OffsetCenterOfMassShapeSettings(Vec3Arg inOffset, const Shape *inShape): DecoratedShapeSettings(inShape), mOffset(inOffset) { }

	// See: ShapeSettings
	virtual ShapeResult				Create() const override;

	Vec3							mOffset;												///< Offset to be applied to the center of mass of the child shape
};

/// This shape will shift the center of mass of a child shape, it can e.g. be used to lower the center of mass of an unstable object like a boat to make it stable
class OffsetCenterOfMassShape final : public DecoratedShape
{
public:
	JPH_OVERRIDE_NEW_DELETE

	/// Constructor
									OffsetCenterOfMassShape() : DecoratedShape(EShapeSubType::OffsetCenterOfMass) { }
									OffsetCenterOfMassShape(const OffsetCenterOfMassShapeSettings &inSettings, ShapeResult &outResult);

	/// Access the offset that is applied to the center of mass
	Vec3							GetOffset() const										{ return mOffset; }

	// See Shape::GetCenterOfMass
	virtual Vec3					GetCenterOfMass() const override						{ return mInnerShape->GetCenterOfMass() + mOffset; }

	// See Shape::GetLocalBounds
	virtual AABox					GetLocalBounds() 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 mInnerShape->GetInnerRadius(); }

	// See Shape::GetMassProperties
	virtual MassProperties			GetMassProperties() const override
	{
		MassProperties mp = mInnerShape->GetMassProperties();
		mp.Translate(mOffset);
		return mp;
	}

	// 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::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::CollectTransformedShapes
	virtual void					CollectTransformedShapes(const AABox &inBox, Vec3Arg inPositionCOM, QuatArg inRotation, Vec3Arg inScale, const SubShapeIDCreator &inSubShapeIDCreator, TransformedShapeCollector &ioCollector, const ShapeFilter &inShapeFilter) 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; }

	// See Shape
	virtual void					SaveBinaryState(StreamOut &inStream) const override;

	// See Shape::GetStats
	virtual Stats					GetStats() const override								{ return Stats(sizeof(*this), 0); }

	// See Shape::GetVolume
	virtual float					GetVolume() const override								{ return mInnerShape->GetVolume(); }

	// See Shape::IsValidScale
	virtual bool					IsValidScale(Vec3Arg inScale) const override			{ return mInnerShape->IsValidScale(inScale); }

	// Register shape functions with the registry
	static void						sRegister();

protected:
	// See: Shape::RestoreBinaryState
	virtual void					RestoreBinaryState(StreamIn &inStream) override;

private:
	// Helper functions called by CollisionDispatch
	static void						sCollideOffsetCenterOfMassVsShape(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						sCollideShapeVsOffsetCenterOfMass(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						sCastOffsetCenterOfMassVsShape(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						sCastShapeVsOffsetCenterOfMass(const ShapeCast &inShapeCast, const ShapeCastSettings &inShapeCastSettings, const Shape *inShape, Vec3Arg inScale, const ShapeFilter &inShapeFilter, Mat44Arg inCenterOfMassTransform2, const SubShapeIDCreator &inSubShapeIDCreator1, const SubShapeIDCreator &inSubShapeIDCreator2, CastShapeCollector &ioCollector);

	Vec3							mOffset;												///< Offset of the center of mass
};

JPH_NAMESPACE_END