source: code/archive/tutorial3/src/external/bullet/LinearMath/btAabbUtil2.h

/*
Copyright (c) 2003-2006 Gino van den Bergen / Erwin Coumans  http://continuousphysics.com/Bullet/

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_AABB_UTIL2
#define BT_AABB_UTIL2

#include "btTransform.h"
#include "btVector3.h"
#include "btMinMax.h"



SIMD_FORCE_INLINE void AabbExpand (btVector3& aabbMin,
                                                                   btVector3& aabbMax,
                                                                   const btVector3& expansionMin,
                                                                   const btVector3& expansionMax)
{
        aabbMin = aabbMin + expansionMin;
        aabbMax = aabbMax + expansionMax;
}

/// conservative test for overlap between two aabbs
SIMD_FORCE_INLINE bool TestPointAgainstAabb2(const btVector3 &aabbMin1, const btVector3 &aabbMax1,
                                                                const btVector3 &point)
{
        bool overlap = true;
        overlap = (aabbMin1.getX() > point.getX() || aabbMax1.getX() < point.getX()) ? false : overlap;
        overlap = (aabbMin1.getZ() > point.getZ() || aabbMax1.getZ() < point.getZ()) ? false : overlap;
        overlap = (aabbMin1.getY() > point.getY() || aabbMax1.getY() < point.getY()) ? false : overlap;
        return overlap;
}


/// conservative test for overlap between two aabbs
SIMD_FORCE_INLINE bool TestAabbAgainstAabb2(const btVector3 &aabbMin1, const btVector3 &aabbMax1,
                                                                const btVector3 &aabbMin2, const btVector3 &aabbMax2)
{
        bool overlap = true;
        overlap = (aabbMin1.getX() > aabbMax2.getX() || aabbMax1.getX() < aabbMin2.getX()) ? false : overlap;
        overlap = (aabbMin1.getZ() > aabbMax2.getZ() || aabbMax1.getZ() < aabbMin2.getZ()) ? false : overlap;
        overlap = (aabbMin1.getY() > aabbMax2.getY() || aabbMax1.getY() < aabbMin2.getY()) ? false : overlap;
        return overlap;
}

/// conservative test for overlap between triangle and aabb
SIMD_FORCE_INLINE bool TestTriangleAgainstAabb2(const btVector3 *vertices,
                                                                        const btVector3 &aabbMin, const btVector3 &aabbMax)
{
        const btVector3 &p1 = vertices[0];
        const btVector3 &p2 = vertices[1];
        const btVector3 &p3 = vertices[2];

        if (btMin(btMin(p1[0], p2[0]), p3[0]) > aabbMax[0]) return false;
        if (btMax(btMax(p1[0], p2[0]), p3[0]) < aabbMin[0]) return false;

        if (btMin(btMin(p1[2], p2[2]), p3[2]) > aabbMax[2]) return false;
        if (btMax(btMax(p1[2], p2[2]), p3[2]) < aabbMin[2]) return false;
  
        if (btMin(btMin(p1[1], p2[1]), p3[1]) > aabbMax[1]) return false;
        if (btMax(btMax(p1[1], p2[1]), p3[1]) < aabbMin[1]) return false;
        return true;
}


SIMD_FORCE_INLINE int   btOutcode(const btVector3& p,const btVector3& halfExtent) 
{
        return (p.getX()  < -halfExtent.getX() ? 0x01 : 0x0) |    
                   (p.getX() >  halfExtent.getX() ? 0x08 : 0x0) |
                   (p.getY() < -halfExtent.getY() ? 0x02 : 0x0) |    
                   (p.getY() >  halfExtent.getY() ? 0x10 : 0x0) |
                   (p.getZ() < -halfExtent.getZ() ? 0x4 : 0x0) |    
                   (p.getZ() >  halfExtent.getZ() ? 0x20 : 0x0);
}



SIMD_FORCE_INLINE bool btRayAabb2(const btVector3& rayFrom,
                                                                  const btVector3& rayInvDirection,
                                                                  const unsigned int raySign[3],
                                                                  const btVector3 bounds[2],
                                                                  btScalar& tmin,
                                                                  btScalar lambda_min,
                                                                  btScalar lambda_max)
{
        btScalar tmax, tymin, tymax, tzmin, tzmax;
        tmin = (bounds[raySign[0]].getX() - rayFrom.getX()) * rayInvDirection.getX();
        tmax = (bounds[1-raySign[0]].getX() - rayFrom.getX()) * rayInvDirection.getX();
        tymin = (bounds[raySign[1]].getY() - rayFrom.getY()) * rayInvDirection.getY();
        tymax = (bounds[1-raySign[1]].getY() - rayFrom.getY()) * rayInvDirection.getY();

        if ( (tmin > tymax) || (tymin > tmax) )
                return false;

        if (tymin > tmin)
                tmin = tymin;

        if (tymax < tmax)
                tmax = tymax;

        tzmin = (bounds[raySign[2]].getZ() - rayFrom.getZ()) * rayInvDirection.getZ();
        tzmax = (bounds[1-raySign[2]].getZ() - rayFrom.getZ()) * rayInvDirection.getZ();

        if ( (tmin > tzmax) || (tzmin > tmax) )
                return false;
        if (tzmin > tmin)
                tmin = tzmin;
        if (tzmax < tmax)
                tmax = tzmax;
        return ( (tmin < lambda_max) && (tmax > lambda_min) );
}

SIMD_FORCE_INLINE bool btRayAabb(const btVector3& rayFrom, 
                                                                 const btVector3& rayTo, 
                                                                 const btVector3& aabbMin, 
                                                                 const btVector3& aabbMax,
                                          btScalar& param, btVector3& normal) 
{
        btVector3 aabbHalfExtent = (aabbMax-aabbMin)* btScalar(0.5);
        btVector3 aabbCenter = (aabbMax+aabbMin)* btScalar(0.5);
        btVector3       source = rayFrom - aabbCenter;
        btVector3       target = rayTo - aabbCenter;
        int     sourceOutcode = btOutcode(source,aabbHalfExtent);
        int targetOutcode = btOutcode(target,aabbHalfExtent);
        if ((sourceOutcode & targetOutcode) == 0x0)
        {
                btScalar lambda_enter = btScalar(0.0);
                btScalar lambda_exit  = param;
                btVector3 r = target - source;
                int i;
                btScalar        normSign = 1;
                btVector3       hitNormal(0,0,0);
                int bit=1;

                for (int j=0;j<2;j++)
                {
                        for (i = 0; i != 3; ++i)
                        {
                                if (sourceOutcode & bit)
                                {
                                        btScalar lambda = (-source[i] - aabbHalfExtent[i]*normSign) / r[i];
                                        if (lambda_enter <= lambda)
                                        {
                                                lambda_enter = lambda;
                                                hitNormal.setValue(0,0,0);
                                                hitNormal[i] = normSign;
                                        }
                                }
                                else if (targetOutcode & bit) 
                                {
                                        btScalar lambda = (-source[i] - aabbHalfExtent[i]*normSign) / r[i];
                                        btSetMin(lambda_exit, lambda);
                                }
                                bit<<=1;
                        }
                        normSign = btScalar(-1.);
                }
                if (lambda_enter <= lambda_exit)
                {
                        param = lambda_enter;
                        normal = hitNormal;
                        return true;
                }
        }
        return false;
}



SIMD_FORCE_INLINE       void btTransformAabb(const btVector3& halfExtents, btScalar margin,const btTransform& t,btVector3& aabbMinOut,btVector3& aabbMaxOut)
{
        btVector3 halfExtentsWithMargin = halfExtents+btVector3(margin,margin,margin);
        btMatrix3x3 abs_b = t.getBasis().absolute();  
        btVector3 center = t.getOrigin();
        btVector3 extent = btVector3(abs_b[0].dot(halfExtentsWithMargin),
                   abs_b[1].dot(halfExtentsWithMargin),
                  abs_b[2].dot(halfExtentsWithMargin));
        aabbMinOut = center - extent;
        aabbMaxOut = center + extent;
}


SIMD_FORCE_INLINE       void btTransformAabb(const btVector3& localAabbMin,const btVector3& localAabbMax, btScalar margin,const btTransform& trans,btVector3& aabbMinOut,btVector3& aabbMaxOut)
{
                btAssert(localAabbMin.getX() <= localAabbMax.getX());
                btAssert(localAabbMin.getY() <= localAabbMax.getY());
                btAssert(localAabbMin.getZ() <= localAabbMax.getZ());
                btVector3 localHalfExtents = btScalar(0.5)*(localAabbMax-localAabbMin);
                localHalfExtents+=btVector3(margin,margin,margin);

                btVector3 localCenter = btScalar(0.5)*(localAabbMax+localAabbMin);
                btMatrix3x3 abs_b = trans.getBasis().absolute();  
                btVector3 center = trans(localCenter);
                btVector3 extent = btVector3(abs_b[0].dot(localHalfExtents),
                           abs_b[1].dot(localHalfExtents),
                          abs_b[2].dot(localHalfExtents));
                aabbMinOut = center-extent;
                aabbMaxOut = center+extent;
}

#define USE_BANCHLESS 1
#ifdef USE_BANCHLESS
        //This block replaces the block below and uses no branches, and replaces the 8 bit return with a 32 bit return for improved performance (~3x on XBox 360)
        SIMD_FORCE_INLINE unsigned testQuantizedAabbAgainstQuantizedAabb(const unsigned short int* aabbMin1,const unsigned short int* aabbMax1,const unsigned short int* aabbMin2,const unsigned short int* aabbMax2)
        {               
                return static_cast<unsigned int>(btSelect((unsigned)((aabbMin1[0] <= aabbMax2[0]) & (aabbMax1[0] >= aabbMin2[0])
                        & (aabbMin1[2] <= aabbMax2[2]) & (aabbMax1[2] >= aabbMin2[2])
                        & (aabbMin1[1] <= aabbMax2[1]) & (aabbMax1[1] >= aabbMin2[1])),
                        1, 0));
        }
#else
        SIMD_FORCE_INLINE bool testQuantizedAabbAgainstQuantizedAabb(const unsigned short int* aabbMin1,const unsigned short int* aabbMax1,const unsigned short int* aabbMin2,const unsigned short int* aabbMax2)
        {
                bool overlap = true;
                overlap = (aabbMin1[0] > aabbMax2[0] || aabbMax1[0] < aabbMin2[0]) ? false : overlap;
                overlap = (aabbMin1[2] > aabbMax2[2] || aabbMax1[2] < aabbMin2[2]) ? false : overlap;
                overlap = (aabbMin1[1] > aabbMax2[1] || aabbMax1[1] < aabbMin2[1]) ? false : overlap;
                return overlap;
        }
#endif //USE_BANCHLESS

#endif //BT_AABB_UTIL2