btCapsuleShape.h

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/*
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
 
ATTRIBUTE_ALIGNED16(class)
btCapsuleShape : public btConvexInternalShape
{
protected:
    int m_upAxis;
 
protected:
    btCapsuleShape() : btConvexInternalShape() { m_shapeType = CAPSULE_SHAPE_PROXYTYPE; };
 
public:
    BT_DECLARE_ALIGNED_ALLOCATOR();
 
    btCapsuleShape(btScalar radius, btScalar height);
 
    virtual void calculateLocalInertia(btScalar mass, btVector3 & inertia) const;
 
    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;
 
    virtual const char* serialize(void* dataBuffer, btSerializer* serializer) const;
 
    SIMD_FORCE_INLINE void deSerializeFloat(struct btCapsuleShapeData * dataBuffer);
};
 
class btCapsuleShapeX : public btCapsuleShape
{
public:
    btCapsuleShapeX(btScalar radius, btScalar height);
 
    //debugging
    virtual const char* getName() const
    {
        return "CapsuleX";
    }
};
 
class btCapsuleShapeZ : public btCapsuleShape
{
public:
    btCapsuleShapeZ(btScalar radius, btScalar height);
 
    //debugging
    virtual const char* getName() const
    {
        return "CapsuleZ";
    }
};
 
struct btCapsuleShapeData
{
    btConvexInternalShapeData m_convexInternalShapeData;
 
    int m_upAxis;
 
    char m_padding[4];
};
 
SIMD_FORCE_INLINE int btCapsuleShape::calculateSerializeBufferSize() const
{
    return sizeof(btCapsuleShapeData);
}
 
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