godot/thirdparty/bullet/BulletCollision/CollisionShapes/btCapsuleShape.h

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef BT_CAPSULE_SHAPE_H
#define BT_CAPSULE_SHAPE_H

#include "btConvexInternalShape.h"
#include "BulletCollision/BroadphaseCollision/btBroadphaseProxy.h"  // for the types

///The btCapsuleShape represents a capsule around the Y axis, there is also the btCapsuleShapeX aligned around the X axis and btCapsuleShapeZ around the Z axis.
///The total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
///The btCapsuleShape is a convex hull of two spheres. The btMultiSphereShape is a more general collision shape that takes the convex hull of multiple sphere, so it can also represent a capsule when just using two spheres.
ATTRIBUTE_ALIGNED16(class)
btCapsuleShape : public btConvexInternalShape
{
protected:
	int m_upAxis;

protected:
	///only used for btCapsuleShapeZ and btCapsuleShapeX subclasses.
	btCapsuleShape() : btConvexInternalShape() { m_shapeType = CAPSULE_SHAPE_PROXYTYPE; };

public:
	BT_DECLARE_ALIGNED_ALLOCATOR();

	btCapsuleShape(btScalar radius, btScalar height);

	///CollisionShape Interface
	virtual void calculateLocalInertia(btScalar mass, btVector3 & inertia) const;

	/// btConvexShape Interface
	virtual btVector3 localGetSupportingVertexWithoutMargin(const btVector3& vec) const;

	virtual void batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const;

	virtual void setMargin(btScalar collisionMargin)
	{
		//don't override the margin for capsules, their entire radius == margin
		(void)collisionMargin;
	}

	virtual void getAabb(const btTransform& t, btVector3& aabbMin, btVector3& aabbMax) const
	{
		btVector3 halfExtents(getRadius(), getRadius(), getRadius());
		halfExtents[m_upAxis] = getRadius() + getHalfHeight();
		btMatrix3x3 abs_b = t.getBasis().absolute();
		btVector3 center = t.getOrigin();
		btVector3 extent = halfExtents.dot3(abs_b[0], abs_b[1], abs_b[2]);

		aabbMin = center - extent;
		aabbMax = center + extent;
	}

	virtual const char* getName() const
	{
		return "CapsuleShape";
	}

	int getUpAxis() const
	{
		return m_upAxis;
	}

	btScalar getRadius() const
	{
		int radiusAxis = (m_upAxis + 2) % 3;
		return m_implicitShapeDimensions[radiusAxis];
	}

	btScalar getHalfHeight() const
	{
		return m_implicitShapeDimensions[m_upAxis];
	}

	virtual void setLocalScaling(const btVector3& scaling)
	{
		btVector3 unScaledImplicitShapeDimensions = m_implicitShapeDimensions / m_localScaling;
		btConvexInternalShape::setLocalScaling(scaling);
		m_implicitShapeDimensions = (unScaledImplicitShapeDimensions * scaling);
		//update m_collisionMargin, since entire radius==margin
		int radiusAxis = (m_upAxis + 2) % 3;
		m_collisionMargin = m_implicitShapeDimensions[radiusAxis];
	}

	virtual btVector3 getAnisotropicRollingFrictionDirection() const
	{
		btVector3 aniDir(0, 0, 0);
		aniDir[getUpAxis()] = 1;
		return aniDir;
	}

	virtual int calculateSerializeBufferSize() const;

	///fills the dataBuffer and returns the struct name (and 0 on failure)
	virtual const char* serialize(void* dataBuffer, btSerializer* serializer) const;

	SIMD_FORCE_INLINE void deSerializeFloat(struct btCapsuleShapeData * dataBuffer);
};

///btCapsuleShapeX represents a capsule around the Z axis
///the total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
class btCapsuleShapeX : public btCapsuleShape
{
public:
	btCapsuleShapeX(btScalar radius, btScalar height);

	//debugging
	virtual const char* getName() const
	{
		return "CapsuleX";
	}
};

///btCapsuleShapeZ represents a capsule around the Z axis
///the total height is height+2*radius, so the height is just the height between the center of each 'sphere' of the capsule caps.
class btCapsuleShapeZ : public btCapsuleShape
{
public:
	btCapsuleShapeZ(btScalar radius, btScalar height);

	//debugging
	virtual const char* getName() const
	{
		return "CapsuleZ";
	}
};

///do not change those serialization structures, it requires an updated sBulletDNAstr/sBulletDNAstr64
struct btCapsuleShapeData
{
	btConvexInternalShapeData m_convexInternalShapeData;

	int m_upAxis;

	char m_padding[4];
};

SIMD_FORCE_INLINE int btCapsuleShape::calculateSerializeBufferSize() const
{
	return sizeof(btCapsuleShapeData);
}

///fills the dataBuffer and returns the struct name (and 0 on failure)
SIMD_FORCE_INLINE const char* btCapsuleShape::serialize(void* dataBuffer, btSerializer* serializer) const
{
	btCapsuleShapeData* shapeData = (btCapsuleShapeData*)dataBuffer;

	btConvexInternalShape::serialize(&shapeData->m_convexInternalShapeData, serializer);

	shapeData->m_upAxis = m_upAxis;

	// Fill padding with zeros to appease msan.
	shapeData->m_padding[0] = 0;
	shapeData->m_padding[1] = 0;
	shapeData->m_padding[2] = 0;
	shapeData->m_padding[3] = 0;

	return "btCapsuleShapeData";
}

SIMD_FORCE_INLINE void btCapsuleShape::deSerializeFloat(btCapsuleShapeData* dataBuffer)
{
	m_implicitShapeDimensions.deSerializeFloat(dataBuffer->m_convexInternalShapeData.m_implicitShapeDimensions);
	m_collisionMargin = dataBuffer->m_convexInternalShapeData.m_collisionMargin;
	m_localScaling.deSerializeFloat(dataBuffer->m_convexInternalShapeData.m_localScaling);
	//it is best to already pre-allocate the matching btCapsuleShape*(X/Z) version to match m_upAxis
	m_upAxis = dataBuffer->m_upAxis;
}

#endif  //BT_CAPSULE_SHAPE_H