#include "CollisionUtil.hpp"
#include "CCollisionInfo.hpp"
#include "CCollisionInfoList.hpp"

namespace urde::CollisionUtil
{

bool LineIntersectsOBBox(const zeus::COBBox& obb, const zeus::CMRay& ray, float& d)
{
    zeus::CVector3f norm;
    return RayAABoxIntersection(ray.getInvUnscaledTransformRay(obb.transform), {-obb.extents, obb.extents},
                                norm, d);
}

u32 RayAABoxIntersection(const zeus::CMRay& ray, const zeus::CAABox& aabb, float& tMin, float& tMax)
{
    tMin = -999999.f;
    tMax = 999999.f;

    for (int i=0 ; i<3 ; ++i)
    {
        if (std::fabs(ray.dir[i]) < 0.00001f)
        {
            if (ray.start[i] < aabb.min[i] || ray.start[i] > aabb.max[i])
                return 0;
        }
        else
        {
            if (ray.dir[i] < 0.f)
            {
                float startToMax = aabb.max[i] - ray.start[i];
                float startToMin = aabb.min[i] - ray.start[i];
                float dirRecip = 1.f / ray.dir[i];
                if (startToMax < tMin * ray.dir[i])
                    tMin = startToMax * dirRecip;
                if (startToMin > tMax * ray.dir[i])
                    tMax = startToMin * dirRecip;
            }
            else
            {
                float startToMin = aabb.min[i] - ray.start[i];
                float startToMax = aabb.max[i] - ray.start[i];
                float dirRecip = 1.f / ray.dir[i];
                if (startToMin > tMin * ray.dir[i])
                    tMin = startToMin * dirRecip;
                if (startToMax < tMax * ray.dir[i])
                    tMax = startToMax * dirRecip;
            }
        }
    }

    return tMin <= tMax ? 2 : 0;
}

u32 RayAABoxIntersection(const zeus::CMRay& ray, const zeus::CAABox& aabb,
                         zeus::CVector3f& norm, float& d)
{
    int sign[] = {2, 2, 2};
    bool bad = true;
    zeus::CVector3f rayStart = ray.start;
    zeus::CVector3f rayDelta = ray.delta;
    zeus::CVector3f aabbMin = aabb.min;
    zeus::CVector3f aabbMax = aabb.max;

    zeus::CVector3f vec0 = {-1.f, -1.f, -1.f};
    zeus::CVector3f vec1;

    if (rayDelta.x != 0.f && rayDelta.y != 0.f && rayDelta.z != 0.f)
    {
        for (int i=0 ; i<3 ; ++i)
        {
            if (rayStart[i] < aabbMin[i])
            {
                sign[i] = 1;
                bad = false;
                vec0[i] = (aabbMin[i] - rayStart[i]) / rayDelta[i];
            }
            else if (rayStart[i] > aabbMax[i])
            {
                sign[i] = 0;
                bad = false;
                vec0[i] = (aabbMax[i] - rayStart[i]) / rayDelta[i];
            }
        }

        if (bad)
        {
            d = 0.f;
            return 1;
        }
    }
    else
    {
        zeus::CVector3f end;
        for (int i=0 ; i<3 ; ++i)
        {
            if (rayStart[i] < aabbMin[i])
            {
                sign[i] = 1;
                bad = false;
                end[i] = aabbMin[i];
            }
            else if (rayStart[i] > aabbMax[i])
            {
                sign[i] = 0;
                bad = false;
                end[i] = aabbMax[i];
            }
        }

        if (bad)
        {
            d = 0.f;
            return 1;
        }

        for (int i=0 ; i<3 ; ++i)
            if (sign[i] != 2 && rayDelta[i] != 0.f)
                vec0[i] = (end[i] - rayStart[i]) / rayDelta[i];
    }

    float maxComp = vec0.x;
    int maxCompIdx = 0;
    if (maxComp < vec0.y)
    {
        maxComp = vec0.y;
        maxCompIdx = 1;
    }
    if (maxComp < vec0.z)
    {
        maxComp = vec0.z;
        maxCompIdx = 2;
    }

    if (maxComp < 0.f || maxComp > 1.f)
        return 0;

    for (int i=0 ; i<3 ; ++i)
    {
        if (maxCompIdx != i)
        {
            vec1[i] = maxComp * rayDelta[i] + rayStart[i];
            if (vec1[i] > aabbMax[i])
                return 0;
        }
    }

    d = maxComp;
    norm = zeus::CVector3f::skZero;
    norm[maxCompIdx] = (sign[maxCompIdx] == 1) ? -1.f : 1.f;
    return 2;
}

u32 RayAABoxIntersection_Double(const zeus::CMRay& ray, const zeus::CAABox& aabb,
                                zeus::CVector3f& norm, double& d)
{
    int sign[] = {2, 2, 2};
    bool bad = true;
    zeus::CVector3d rayStart = ray.start;
    zeus::CVector3d rayDelta = ray.delta;
    zeus::CVector3d aabbMin = aabb.min;
    zeus::CVector3d aabbMax = aabb.max;

    zeus::CVector3d vec0 = {-1.0, -1.0, -1.0};
    zeus::CVector3d vec1;

    if (rayDelta.x != 0.0 && rayDelta.y != 0.0 && rayDelta.z != 0.0)
    {
        for (int i=0 ; i<3 ; ++i)
        {
            if (rayStart[i] < aabbMin[i])
            {
                sign[i] = 1;
                bad = false;
                vec0[i] = (aabbMin[i] - rayStart[i]) / rayDelta[i];
            }
            else if (rayStart[i] > aabbMax[i])
            {
                sign[i] = 0;
                bad = false;
                vec0[i] = (aabbMax[i] - rayStart[i]) / rayDelta[i];
            }
        }

        if (bad)
        {
            d = 0.0;
            return 1;
        }
    }
    else
    {
        zeus::CVector3d end;
        for (int i=0 ; i<3 ; ++i)
        {
            if (rayStart[i] < aabbMin[i])
            {
                sign[i] = 1;
                bad = false;
                end[i] = aabbMin[i];
            }
            else if (rayStart[i] > aabbMax[i])
            {
                sign[i] = 0;
                bad = false;
                end[i] = aabbMax[i];
            }
        }

        if (bad)
        {
            d = 0.0;
            return 1;
        }

        for (int i=0 ; i<3 ; ++i)
            if (sign[i] != 2 && rayDelta[i] != 0.0)
                vec0[i] = (end[i] - rayStart[i]) / rayDelta[i];
    }

    double maxComp = vec0.x;
    int maxCompIdx = 0;
    if (maxComp < vec0.y)
    {
        maxComp = vec0.y;
        maxCompIdx = 1;
    }
    if (maxComp < vec0.z)
    {
        maxComp = vec0.z;
        maxCompIdx = 2;
    }

    if (maxComp < 0.0 || maxComp > 1.0)
        return 0;

    for (int i=0 ; i<3 ; ++i)
    {
        if (maxCompIdx != i)
        {
            vec1[i] = maxComp * rayDelta[i] + rayStart[i];
            if (vec1[i] > aabbMax[i])
                return 0;
        }
    }

    d = maxComp;
    norm = zeus::CVector3f::skZero;
    norm[maxCompIdx] = (sign[maxCompIdx] == 1) ? -1.0 : 1.0;
    return 2;
}

bool RaySphereIntersection_Double(const zeus::CSphere& sphere, const zeus::CVector3f& pos,
                                  const zeus::CVector3f& dir, double& T)
{
    zeus::CVector3d sPosD = sphere.position;
    zeus::CVector3d posD = pos;
    zeus::CVector3d sphereToPos = posD - sPosD;
    double f30 = sphereToPos.dot(zeus::CVector3d(dir)) * 2.0;
    double f1 = f30 * f30 - 4.0 * (sphereToPos.magSquared() - sphere.radius * sphere.radius);
    if (f1 >= 0.0)
    {
        double intersectT = 0.5 * (-f30 - std::sqrt(f1));
        if (T == 0 || intersectT < T)
        {
            T = intersectT;
            return true;
        }
    }
    return false;
}

bool RaySphereIntersection(const zeus::CSphere& sphere, const zeus::CVector3f& pos, const zeus::CVector3f& dir,
                           float mag, float& T, zeus::CVector3f& point)
{
    zeus::CVector3f rayToSphere = sphere.position - pos;
    float magSq = rayToSphere.magSquared();
    float dirDot = rayToSphere.dot(dir);
    float radSq = sphere.radius * sphere.radius;
    if (dirDot < 0.f && magSq > radSq)
        return false;
    float intersectSq = radSq - (magSq - dirDot * dirDot);
    if (intersectSq < 0.f)
        return false;
    T = magSq > radSq ? dirDot - std::sqrt(intersectSq) : dirDot + std::sqrt(intersectSq);
    if (T < mag || mag == 0.f)
    {
        point = pos + T * dir;
        return true;
    }
    return false;
}

bool RayTriangleIntersection_Double(const zeus::CVector3f& point, const zeus::CVector3f& dir,
                                    const zeus::CVector3f* verts, double& d)
{
    zeus::CVector3d v0tov1 = verts[1] - verts[0];
    zeus::CVector3d v0tov2 = verts[2] - verts[0];
    zeus::CVector3d cross0 = zeus::CVector3d(dir).cross(v0tov2);
    double dot0 = v0tov1.dot(cross0);
    if (dot0 < DBL_EPSILON)
        return false;
    zeus::CVector3d v0toPoint = point - verts[0];
    double dot1 = v0toPoint.dot(cross0);
    if (dot1 < 0.0 || dot1 > dot0)
        return false;
    zeus::CVector3d cross1 = v0toPoint.cross(v0tov1);
    double dot2 = cross1.dot(dir);
    if (dot2 < 0.0 || dot1 + dot2 > dot0)
        return false;
    double final = 1.0 / dot0 * cross1.dot(v0tov2);
    if (final < 0.0 || final >= d)
        return false;
    d = final;
    return true;
}

bool RayTriangleIntersection(const zeus::CVector3f& point, const zeus::CVector3f& dir,
                             const zeus::CVector3f* verts, float& d)
{
    zeus::CVector3f v0tov1 = verts[1] - verts[0];
    zeus::CVector3f v0tov2 = verts[2] - verts[0];
    zeus::CVector3f cross0 = dir.cross(v0tov2);
    float dot0 = v0tov1.dot(cross0);
    if (dot0 < DBL_EPSILON)
        return false;
    zeus::CVector3f v0toPoint = point - verts[0];
    float dot1 = v0toPoint.dot(cross0);
    if (dot1 < 0.f || dot1 > dot0)
        return false;
    zeus::CVector3f cross1 = v0toPoint.cross(v0tov1);
    float dot2 = cross1.dot(dir);
    if (dot2 < 0.f || dot1 + dot2 > dot0)
        return false;
    float final = 1.f / dot0 * cross1.dot(v0tov2);
    if (final < 0.f || final >= d)
        return false;
    d = final;
    return true;
}

void FilterOutBackfaces(const zeus::CVector3f& vec, const CCollisionInfoList& in, CCollisionInfoList& out)
{
    if (vec.canBeNormalized())
    {
        zeus::CVector3f norm = vec.normalized();
        for (const CCollisionInfo& info : in)
        {
            if (info.GetNormalLeft().dot(norm) < 0.001f)
                out.Add(info, false);
        }
    }
    else
    {
        out = in;
    }
}

void FilterByClosestNormal(const zeus::CVector3f& norm, const CCollisionInfoList& in, CCollisionInfoList& out)
{
    float maxDot = -1.1f;
    int idx = -1;
    int i=0;
    for (const CCollisionInfo& info : in)
    {
        float dot = info.GetNormalLeft().dot(norm);
        if (dot > maxDot)
        {
            maxDot = dot;
            idx = i;
        }
        ++i;
    }

    if (idx != -1)
        out.Add(in.GetItem(i), false);
}

static const zeus::CVector3f AABBNormalTable[] =
{
    {-1.f, 0.f, 0.f},
    {1.f, 0.f, 0.f},
    {0.f, -1.f, 0.f},
    {0.f, 1.f, 0.f},
    {0.f, 0.f, -1.f},
    {0.f, 0.f, 1.f}
};

bool AABoxAABoxIntersection(const zeus::CAABox& aabb0, const CMaterialList& list0,
                            const zeus::CAABox& aabb1, const CMaterialList& list1,
                            CCollisionInfoList& infoList)
{
    zeus::CVector3f maxOfMin(std::max(aabb0.min.x, aabb1.min.x),
                             std::max(aabb0.min.y, aabb1.min.y),
                             std::max(aabb0.min.z, aabb1.min.z));
    zeus::CVector3f minOfMax(std::min(aabb0.max.x, aabb1.max.x),
                             std::min(aabb0.max.y, aabb1.max.y),
                             std::min(aabb0.max.z, aabb1.max.z));

    if (maxOfMin.x >= minOfMax.x || maxOfMin.y >= minOfMax.y || maxOfMin.z >= minOfMax.z)
        return false;

    zeus::CAABox boolAABB(maxOfMin, minOfMax);

    int ineqFlags[] =
    {
        (aabb0.min.x <= aabb1.min.x ? 1 << 0 : 0) |
        (aabb0.min.x <= aabb1.max.x ? 1 << 1 : 0) |
        (aabb0.max.x <= aabb1.min.x ? 1 << 2 : 0) |
        (aabb0.max.x <= aabb1.max.x ? 1 << 3 : 0),
        (aabb0.min.y <= aabb1.min.y ? 1 << 0 : 0) |
        (aabb0.min.y <= aabb1.max.y ? 1 << 1 : 0) |
        (aabb0.max.y <= aabb1.min.y ? 1 << 2 : 0) |
        (aabb0.max.y <= aabb1.max.y ? 1 << 3 : 0),
        (aabb0.min.z <= aabb1.min.z ? 1 << 0 : 0) |
        (aabb0.min.z <= aabb1.max.z ? 1 << 1 : 0) |
        (aabb0.max.z <= aabb1.min.z ? 1 << 2 : 0) |
        (aabb0.max.z <= aabb1.max.z ? 1 << 3 : 0),
    };

    for (int i=0 ; i<3 ; ++i)
    {
        switch (ineqFlags[i])
        {
        case 0x2: // aabb0.min <= aabb1.max
        {
            CCollisionInfo info(boolAABB, list0, list1, AABBNormalTable[i*2+1], -AABBNormalTable[i*2+1]);
            infoList.Add(info, false);
            break;
        }
        case 0xB: // aabb0.min <= aabb1.min && aabb0.max <= aabb1.min && aabb0.max <= aabb1.max
        {
            CCollisionInfo info(boolAABB, list0, list1, AABBNormalTable[i*2], -AABBNormalTable[i*2]);
            infoList.Add(info, false);
            break;
        }
        default: break;
        }
    }

    if (infoList.GetCount())
        return true;

    {
        CCollisionInfo info(boolAABB, list0, list1, AABBNormalTable[4], -AABBNormalTable[4]);
        infoList.Add(info, false);
    }

    {
        CCollisionInfo info(boolAABB, list0, list1, AABBNormalTable[5], -AABBNormalTable[5]);
        infoList.Add(info, false);
    }

    return true;
}

bool AABoxAABoxIntersection(const zeus::CAABox& aabb0, const zeus::CAABox& aabb1)
{
    return aabb0.intersects(aabb1);
}

/* http://fileadmin.cs.lth.se/cs/Personal/Tomas_Akenine-Moller/code/tribox2.txt */
/********************************************************/
/* AABB-triangle overlap test code                      */
/* by Tomas Akenine-Möller                              */
/* Function: int triBoxOverlap(float boxcenter[3],      */
/*          float boxhalfsize[3],float triverts[3][3]); */
/* History:                                             */
/*   2001-03-05: released the code in its first version */
/*   2001-06-18: changed the order of the tests, faster */
/*                                                      */
/* Acknowledgement: Many thanks to Pierre Terdiman for  */
/* suggestions and discussions on how to optimize code. */
/* Thanks to David Hunt for finding a ">="-bug!         */
/********************************************************/

#define FINDMINMAX(x0,x1,x2,min,max) \
    min = max = x0;   \
    if (x1<min) min = x1;\
    if (x1>max) max = x1;\
    if (x2<min) min = x2;\
    if (x2>max) max = x2;

static bool planeBoxOverlap(const zeus::CVector3f& normal, float d, const zeus::CVector3f& maxbox)
{
    zeus::CVector3f vmin, vmax;
    for (int q=0 ; q<=2 ; q++)
    {
        if (normal[q] > 0.0f)
        {
            vmin[q] = -maxbox[q];
            vmax[q] = maxbox[q];
        }
        else
        {
            vmin[q] = maxbox[q];
            vmax[q] = -maxbox[q];
        }
    }
    if (normal.dot(vmin) + d > 0.0f) return false;
    if (normal.dot(vmax) + d >= 0.0f) return true;

    return false;
}


/*======================== X-tests ========================*/
#define AXISTEST_X01(a, b, fa, fb)             \
    p0 = a*v0.y - b*v0.z;                    \
    p2 = a*v2.y - b*v2.z;                    \
    if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;} \
    rad = fa * boxhalfsize.y + fb * boxhalfsize.z;   \
    if(min>rad || max<-rad) return false;

#define AXISTEST_X2(a, b, fa, fb)              \
    p0 = a*v0.y - b*v0.z;                    \
    p1 = a*v1.y - b*v1.z;                    \
    if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
    rad = fa * boxhalfsize.y + fb * boxhalfsize.z;   \
    if(min>rad || max<-rad) return false;

/*======================== Y-tests ========================*/
#define AXISTEST_Y02(a, b, fa, fb)             \
    p0 = -a*v0.x + b*v0.z;                   \
    p2 = -a*v2.x + b*v2.z;                       \
    if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;} \
    rad = fa * boxhalfsize.x + fb * boxhalfsize.z;   \
    if(min>rad || max<-rad) return false;

#define AXISTEST_Y1(a, b, fa, fb)              \
    p0 = -a*v0.x + b*v0.z;                   \
    p1 = -a*v1.x + b*v1.z;                       \
    if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
    rad = fa * boxhalfsize.x + fb * boxhalfsize.z;   \
    if(min>rad || max<-rad) return false;

/*======================== Z-tests ========================*/

#define AXISTEST_Z12(a, b, fa, fb)             \
    p1 = a*v1.x - b*v1.y;                    \
    p2 = a*v2.x - b*v2.y;                    \
    if(p2<p1) {min=p2; max=p1;} else {min=p1; max=p2;} \
    rad = fa * boxhalfsize.x + fb * boxhalfsize.y;   \
    if(min>rad || max<-rad) return false;

#define AXISTEST_Z0(a, b, fa, fb)              \
    p0 = a*v0.x - b*v0.y;                \
    p1 = a*v1.x - b*v1.y;                    \
    if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;} \
    rad = fa * boxhalfsize.x + fb * boxhalfsize.y;   \
    if(min>rad || max<-rad) return false;

bool TriBoxOverlap(const zeus::CVector3f& boxcenter, const zeus::CVector3f& boxhalfsize,
                   const zeus::CVector3f& trivert0, const zeus::CVector3f& trivert1,
                   const zeus::CVector3f& trivert2)
{

    /*    use separating axis theorem to test overlap between triangle and box */
    /*    need to test for overlap in these directions: */
    /*    1) the {x,y,z}-directions (actually, since we use the AABB of the triangle */
    /*       we do not even need to test these) */
    /*    2) normal of the triangle */
    /*    3) crossproduct(edge from tri, {x,y,z}-directin) */
    /*       this gives 3x3=9 more tests */
    zeus::CVector3f v0, v1, v2;
    float min, max, d, p0, p1, p2, rad, fex, fey, fez;
    zeus::CVector3f normal, e0, e1, e2;

    /* This is the fastest branch on Sun */
    /* move everything so that the boxcenter is in (0,0,0) */
    v0 = trivert0 - boxcenter;
    v1 = trivert1 - boxcenter;
    v2 = trivert2 - boxcenter;

    /* compute triangle edges */
    e0 = v1 - v0;      /* tri edge 0 */
    e1 = v2 - v1;      /* tri edge 1 */
    e2 = v0 - v2;      /* tri edge 2 */

    /* Bullet 3:  */
    /*  test the 9 tests first (this was faster) */
    fex = std::fabs(e0.x);
    fey = std::fabs(e0.y);
    fez = std::fabs(e0.z);
    AXISTEST_X01(e0.z, e0.y, fez, fey);
    AXISTEST_Y02(e0.z, e0.x, fez, fex);
    AXISTEST_Z12(e0.y, e0.x, fey, fex);

    fex = std::fabs(e1.x);
    fey = std::fabs(e1.y);
    fez = std::fabs(e1.z);
    AXISTEST_X01(e1.z, e1.y, fez, fey);
    AXISTEST_Y02(e1.z, e1.x, fez, fex);
    AXISTEST_Z0(e1.y, e1.x, fey, fex);

    fex = std::fabs(e2.x);
    fey = std::fabs(e2.y);
    fez = std::fabs(e2.z);
    AXISTEST_X2(e2.z, e2.y, fez, fey);
    AXISTEST_Y1(e2.z, e2.x, fez, fex);
    AXISTEST_Z12(e2.y, e2.x, fey, fex);

    /* Bullet 1: */
    /*  first test overlap in the {x,y,z}-directions */
    /*  find min, max of the triangle each direction, and test for overlap in */
    /*  that direction -- this is equivalent to testing a minimal AABB around */
    /*  the triangle against the AABB */

    /* test in X-direction */
    FINDMINMAX(v0.x, v1.x, v2.x, min, max);
    if (min>boxhalfsize.x || max<-boxhalfsize.x) return false;

    /* test in Y-direction */
    FINDMINMAX(v0.y, v1.y, v2.y, min, max);
    if (min>boxhalfsize.y || max<-boxhalfsize.y) return false;

    /* test in Z-direction */
    FINDMINMAX(v0.z, v1.z, v2.z, min, max);
    if (min>boxhalfsize.z || max<-boxhalfsize.z) return false;

    /* Bullet 2: */
    /*  test if the box intersects the plane of the triangle */
    /*  compute plane equation of triangle: normal*x+d=0 */
    normal = e0.cross(e1);
    d = -normal.dot(v0);  /* plane eq: normal.x+d=0 */
    if (!planeBoxOverlap(normal, d, boxhalfsize)) return false;

    return true;   /* box and triangle overlaps */
}

double TriPointSqrDist(const zeus::CVector3f& point,
                       const zeus::CVector3f& trivert0, const zeus::CVector3f& trivert1,
                       const zeus::CVector3f& trivert2, float* baryX, float* baryY)
{
    zeus::CVector3d A = trivert0 - point;
    zeus::CVector3d B = trivert1 - trivert0;
    zeus::CVector3d C = trivert2 - trivert0;

    double bMag = B.magSquared();
    double cMag = C.magSquared();
    double bDotC = B.dot(C);
    double aDotB = A.dot(B);
    double aDotC = A.dot(C);
    double ret = A.magSquared();

    double rej = std::fabs(bMag * cMag - bDotC * bDotC);
    double retB = bDotC * aDotC - cMag * aDotB;
    double retA = bDotC * aDotB - bMag * aDotC;

    if (retB + retA <= rej)
    {
        if (retB < 0.0)
        {
            if (retA < 0.0)
            {
                if (aDotB < 0.0)
                {
                    retA = 0.0;
                    if (-aDotB >= bMag)
                    {
                        retB = 1.0;
                        ret += 2.0 * aDotB + bMag;
                    }
                    else
                    {
                        retB = -aDotB / bMag;
                        ret += aDotB * retB;
                    }
                }
                else
                {
                    retB = 0.0;
                    if (aDotC >= 0.0)
                    {
                        retA = 0.0;
                    }
                    else if (-aDotC >= cMag)
                    {
                        retA = 1.0;
                        ret += 2.0 * aDotC + cMag;
                    }
                    else
                    {
                        retA = -aDotC / cMag;
                        ret += aDotC * retA;
                    }
                }
            }
            else
            {
                retB = 0.0;
                if (aDotC >= 0.0)
                {
                    retA = 0.0;
                }
                else if (-aDotC >= cMag)
                {
                    retA = 1.0;
                    ret += 2.0 * aDotC + cMag;
                }
                else
                {
                    retA = -aDotC / cMag;
                    ret += aDotC * retA;
                }
            }
        }
        else if (retA < 0.0)
        {
            retA = 0.0;
            if (aDotB >= 0.0)
            {
                retB = 0.0;
            }
            else if (-aDotB >= bMag)
            {
                retB = 1.0;
                ret += 2.0 * aDotB + bMag;
            }
            else
            {
                retB = -aDotB / bMag;
                ret += aDotB * retB;
            }
        }
        else
        {
            float f3 = 1.0 / rej;
            retA *= f3;
            retB *= f3;
            ret += retB * (2.0 * aDotB + (bMag * retB + bDotC * retA)) +
                   retA * (2.0 * aDotC + (bDotC * retB + cMag * retA));
        }
    }
    else if (retB < 0.0)
    {
        retB = bDotC + aDotB;
        retA = cMag + aDotC;
        if (retA > retB)
        {
            retA -= retB;
            retB = bMag - 2.0 * bDotC;
            retB += cMag;
            if (retA >= retB)
            {
                retB = 1.0;
                retA = 0.0;
                ret += 2.0 * aDotB + bMag;
            }
            else
            {
                retB = retA / retB;
                retA = 1.0 - retB;
                ret += retB * (2.0 * aDotB + (bMag * retB + bDotC * retA)) +
                       retA * (2.0 * aDotC + (bDotC * retB + cMag * retA));
            }
        }
        else
        {
            retB = 0.0;
            if (retA <= 0.0)
            {
                retA = 1.0;
                ret += 2.0 * aDotC + cMag;
            }
            else if (aDotC >= 0.0)
            {
                retA = 0.0;
            }
            else
            {
                retA = -aDotC / cMag;
                ret += aDotC * retA;
            }
        }
    }
    else
    {
        if (retA < 0.0)
        {
            retB = bDotC + aDotC;
            retA = bMag + aDotB;
            if (retA > retB)
            {
                retA -= retB;
                retB = bMag - 2.0 * bDotC;
                retB += cMag;
                if (retA >= retB)
                {
                    retA = 1.0;
                    retB = 0.0;
                    ret += 2.0 * aDotC + cMag;
                }
                else
                {
                    retA /= retB;
                    retB = 1.0 - retA;
                    ret += retB * (2.0 * aDotB + (bMag * retB + bDotC * retA)) +
                           retA * (2.0 * aDotC + (bDotC * retB + cMag * retA));
                }
            }
            else
            {
                retA = 0.0;
                if (retA <= 0.0)
                {
                    retB = 1.0;
                    ret += 2.0 * aDotB + bMag;
                }
                else if (aDotB >= 0.0)
                {
                    retB = 0.0;
                }
                else
                {
                    retB = -aDotB / bMag;
                    ret += aDotB * retB;
                }
            }
        }
        else
        {
            retB = cMag + aDotC;
            retB -= bDotC;
            retA = retB - aDotB;
            if (retA <= 0.0)
            {
                retB = 0.0;
                retA = 1.0;
                ret += 2.0 * aDotC + cMag;
            }
            else
            {
                retB = bMag - 2.0 * bDotC;
                retB += cMag;
                if (retA >= retB)
                {
                    retB = 1.0;
                    retA = 0.0;
                    ret += 2.0 * aDotB + bMag;
                }
                else
                {
                    retB = retA / retB;
                    retA = 1.0 - retB;
                    ret += retB * (2.0 * aDotB + (bMag * retB + bDotC * retA)) +
                           retA * (2.0 * aDotC + (bDotC * retB + cMag * retA));
                }
            }
        }
    }

    if (baryX)
        *baryX = retA;
    if (baryY)
        *baryY = retB;

    return ret;
}

bool TriSphereOverlap(const zeus::CSphere& sphere,
                      const zeus::CVector3f& trivert0, const zeus::CVector3f& trivert1,
                      const zeus::CVector3f& trivert2)
{
    return TriPointSqrDist(sphere.position, trivert0, trivert1, trivert2, nullptr, nullptr) <=
           sphere.radius * sphere.radius;
}

bool TriSphereIntersection(const zeus::CSphere& sphere,
                           const zeus::CVector3f& trivert0, const zeus::CVector3f& trivert1,
                           const zeus::CVector3f& trivert2, zeus::CVector3f& point, zeus::CVector3f& normal)
{
    float baryX, baryY;
    if (TriPointSqrDist(sphere.position, trivert0, trivert1, trivert2, &baryX, &baryY) >
        sphere.radius * sphere.radius)
        return false;

    zeus::CVector3f barys(baryX, baryY, 1.f - (baryX + baryY));
    point = zeus::baryToWorld(trivert2, trivert1, trivert0, barys);

    if (baryX == 0.f || baryX == 1.f || baryY == 0.f || baryY == 1.f ||
        barys.z == 0.f || barys.z == 1.f)
        normal = -sphere.getSurfaceNormal(point);
    else
        normal = (trivert1 - trivert0).cross(trivert2 - trivert0).normalized();

    return true;
}

bool BoxLineTest(const zeus::CAABox& aabb, const zeus::CVector3f& point, const zeus::CVector3f& dir,
                 float& tMin, float& tMax, int& axis, bool& sign)
{
    tMin = -999999.f;
    tMax = 999999.f;

    for (int i=0 ; i<3 ; ++i)
    {
        if (dir[i] == 0.f)
            if (point[i] < aabb.min[i] || point[i] > aabb.max[i])
                return false;

        float dirRecip = 1.f / dir[i];
        float tmpMin, tmpMax;
        if (dir[i] < 0.f)
        {
            tmpMin = (aabb.max[i] - point[i]) * dirRecip;
            tmpMax = (aabb.min[i] - point[i]) * dirRecip;
        }
        else
        {
            tmpMin = (aabb.min[i] - point[i]) * dirRecip;
            tmpMax = (aabb.max[i] - point[i]) * dirRecip;
        }

        if (tmpMin > tMin)
        {
            sign = dir[i] < 0.f;
            axis = i;
            tMin = tmpMin;
        }

        if (tmpMax < tMax)
            tMax = tmpMax;
    }

    return tMin <= tMax;
}

bool LineCircleIntersection2d(const zeus::CVector3f& point, const zeus::CVector3f& dir, const zeus::CSphere& sphere,
                              int axis1, int axis2, float& d)
{
    zeus::CVector3f delta = sphere.position - point;
    zeus::CVector2f deltaVec(delta[axis1], delta[axis2]);
    zeus::CVector2f dirVec(dir[axis1], dir[axis2]);

    float dirVecMag = dirVec.magnitude();
    if (dirVecMag < FLT_EPSILON)
        return false;

    float deltaVecDot = deltaVec.dot(dirVec / dirVecMag);
    float deltaVecMagSq = deltaVec.magSquared();

    float sphereRadSq = sphere.radius * sphere.radius;
    if (deltaVecDot < 0.f && deltaVecMagSq > sphereRadSq)
        return false;

    float tSq = sphereRadSq - (deltaVecMagSq - deltaVecDot * deltaVecDot);
    if (tSq < 0.f)
        return false;

    float t = std::sqrt(tSq);

    d = (deltaVecMagSq > sphereRadSq) ? deltaVecDot - t : deltaVecDot + t;
    d /= dirVecMag;

    return true;
}

bool MovingSphereAABox(const zeus::CSphere& sphere, const zeus::CAABox& aabb, const zeus::CVector3f& dir,
                       double& dOut, zeus::CVector3f& point, zeus::CVector3f& normal)
{
    zeus::CAABox expAABB(aabb.min - sphere.radius, aabb.max + sphere.radius);
    float tMin, tMax;
    int axis;
    bool sign;
    if (!BoxLineTest(expAABB, sphere.position, dir, tMin, tMax, axis, sign))
        return false;

    point = sphere.position + tMin * dir;

    int nextAxis1 = (axis+1) % 3; // r0
    int nextAxis2 = (axis+2) % 3; // r5

    bool inMin1 = point[nextAxis1] >= aabb.min[nextAxis1]; // r6
    bool inMax1 = point[nextAxis1] <= aabb.max[nextAxis1]; // r8
    bool inBounds1 = inMin1 && inMax1; // r9
    bool inMin2 = point[nextAxis2] >= aabb.min[nextAxis2]; // r7
    bool inMax2 = point[nextAxis2] <= aabb.max[nextAxis2]; // r4
    bool inBounds2 = inMin2 && inMax2; // r8

    if (inBounds1 && inBounds2)
    {
        if (tMin < 0.f || tMin > dOut)
            return false;
        normal[axis] = sign ? 1.f : -1.f;
        dOut = tMin;
        point -= normal * sphere.radius;
        return true;
    }
    else if (!inBounds1 && !inBounds2)
    {
        int pointFlags = (1 << axis) * sign | (1 << nextAxis1) * inMin1 | (1 << nextAxis2) * inMin2;
        zeus::CVector3f aabbPoint = aabb.getPoint(pointFlags);
        float d;
        if (CollisionUtil::RaySphereIntersection(zeus::CSphere(aabbPoint, sphere.radius),
                                                 sphere.position, dir, dOut, d, point))
        {
            int useAxis = -1;
            for (int i=0 ; i<3 ; ++i)
            {
                if ((pointFlags & (1 << i)) ? aabbPoint[i] > point[i] : aabbPoint[i] < point[i])
                {
                    useAxis = i;
                    break;
                }
            }

            if (useAxis == -1)
            {
                normal = (point - aabbPoint).normalized();
                point -= sphere.radius * normal;
                return true;
            }

            int useAxisNext1 = (useAxis+1) % 3;
            int useAxisNext2 = (useAxis+2) % 3;

            float d;
            if (CollisionUtil::LineCircleIntersection2d(sphere.position, dir, zeus::CSphere(aabbPoint, sphere.radius),
                                                        useAxisNext1, useAxisNext2, d) && d > 0.f && d < dOut)
            {
                if (point[useAxis] > aabb.max[useAxis])
                {
                    int useAxisBit = 1 << useAxis;
                    if (pointFlags & useAxisBit)
                        return false;

                    zeus::CVector3f aabbPoint1 = aabb.getPoint(pointFlags | useAxisBit);
                    if (CollisionUtil::RaySphereIntersection(zeus::CSphere(aabbPoint1, sphere.radius),
                                                             sphere.position, dir, dOut, d, point))
                    {
                        dOut = d;
                        normal = (point - aabbPoint1).normalized();
                        point -= normal * sphere.radius;
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                else if (point[useAxis] < aabb.min[useAxis])
                {
                    int useAxisBit = 1 << useAxis;
                    if (!(pointFlags & useAxisBit))
                        return false;

                    zeus::CVector3f aabbPoint1 = aabb.getPoint(pointFlags ^ useAxisBit);
                    if (CollisionUtil::RaySphereIntersection(zeus::CSphere(aabbPoint1, sphere.radius),
                                                             sphere.position, dir, dOut, d, point))
                    {
                        dOut = d;
                        normal = (point - aabbPoint1).normalized();
                        point -= normal * sphere.radius;
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                else
                {
                    normal = point - aabbPoint;
                    normal.normalize();
                    point -= normal * sphere.radius;
                    return true;
                }
            }
        }
        else
        {
            int reverseCount = 0;
            float dMin = 1.0e10f;
            int minAxis = 0;
            for (int i=0 ; i<3 ; ++i)
            {
                if (std::fabs(dir[i]) > FLT_EPSILON)
                {
                    bool pointMax = pointFlags & (1 << i);
                    if (pointMax != dir[i] > 0.f)
                    {
                        ++reverseCount;
                        float d = 1.f / dir[i] * ((pointMax ? aabb.max[i] : aabb.min[i]) - sphere.position[i]);
                        if (d < 0.f)
                            return false;
                        if (d < dMin)
                        {
                            dMin = d;
                            minAxis = i;
                        }
                    }
                }
            }

            if (reverseCount < 2)
                return false;

            int useAxisNext1 = (minAxis+1) % 3;
            int useAxisNext2 = (minAxis+2) % 3;
            float d;
            if (CollisionUtil::LineCircleIntersection2d(sphere.position, dir, zeus::CSphere(aabbPoint, sphere.radius),
                                                        useAxisNext1, useAxisNext2, d) && d > 0.f && d < dOut)
            {
                point = sphere.position + d * dir;
                if (point[minAxis] > aabb.max[minAxis])
                    return false;
                if (point[minAxis] < aabb.min[minAxis])
                    return false;

                dOut = d;
                normal = point - aabbPoint;
                normal.normalize();
                point -= sphere.radius * normal;
                return true;
            }
            else
            {
                return false;
            }
        }
    }

    bool useNextAxis1 = inBounds1 ? nextAxis2 : nextAxis1;
    bool useNextAxis2 = inBounds1 ? nextAxis1 : nextAxis2;

    int pointFlags = ((1 << int(useNextAxis1)) * (inBounds1 ? inMin2 : inMin1)) | ((1 << axis) * sign);
    zeus::CVector3f aabbPoint2 = aabb.getPoint(pointFlags);
    float d;
    if (LineCircleIntersection2d(sphere.position, dir, zeus::CSphere(aabbPoint2, sphere.radius),
                                 axis, useNextAxis1, d) && d > 0.f && d < dOut)
    {
        point = sphere.position + d * dir;
        if (point[useNextAxis2] > aabb.max[useNextAxis2])
        {
            zeus::CVector3f aabbPoint3 = aabb.getPoint(pointFlags | (1 << int(useNextAxis2)));
            if (point[useNextAxis2] < expAABB.max[useNextAxis2])
            {
                if (RaySphereIntersection(zeus::CSphere(aabbPoint3, sphere.radius),
                                          sphere.position, dir, dOut, d, point))
                {
                    dOut = d;
                    normal = (point - aabbPoint3).normalized();
                    point -= sphere.radius * normal;
                    return true;
                }
            }
            return false;
        }
        else if (point[useNextAxis2] < aabb.min[useNextAxis2])
        {
            if (point[useNextAxis2] > expAABB.min[useNextAxis2])
            {
                if (RaySphereIntersection(zeus::CSphere(aabbPoint2, sphere.radius),
                                          sphere.position, dir, dOut, d, point))
                {
                    dOut = d;
                    normal = (point - aabbPoint2).normalized();
                    point -= sphere.radius * normal;
                    return true;
                }
            }
            return false;
        }
        else
        {
            dOut = d;
            normal = point - aabbPoint2;
            normal.normalize();
            point -= sphere.radius * normal;
            return true;
        }
    }

    return false;
}

bool AABox_AABox_Moving(const zeus::CAABox& aabb0, const zeus::CAABox& aabb1, const zeus::CVector3f& dir,
                        double& d, zeus::CVector3f& point, zeus::CVector3f& normal)
{
    zeus::CVector3d vecMin(DBL_MIN);
    zeus::CVector3d vecMax(DBL_MAX);

    for (int i=0 ; i<3 ; ++i)
    {
        if (std::fabs(dir[i]) < FLT_EPSILON)
        {
            if (aabb0.min[i] >= aabb1.min[i] && aabb0.min[i] <= aabb1.max[i])
                continue;
            if (aabb0.max[i] >= aabb1.min[i] && aabb0.max[i] <= aabb1.max[i])
                continue;
            if (aabb0.min[i] < aabb1.min[i] && aabb0.max[i] > aabb1.max[i])
                continue;
            return false;
        }
        else
        {
            if (aabb0.max[i] < aabb1.min[i] && dir[i] > 0.f)
                vecMin[i] = (aabb1.min[i] - aabb0.max[i]) / dir[i];
            else if (aabb1.max[i] < aabb0.min[i] && dir[i] < 0.f)
                vecMin[i] = (aabb1.max[i] - aabb0.min[i]) / dir[i];
            else if (aabb1.max[i] > aabb0.min[i] && dir[i] < 0.f)
                vecMin[i] = (aabb1.max[i] - aabb0.min[i]) / dir[i];
            else if (aabb0.max[i] > aabb1.min[i] && dir[i] > 0.f)
                vecMin[i] = (aabb1.min[i] - aabb0.max[i]) / dir[i];

            if (aabb1.max[i] > aabb0.min[i] && dir[i] > 0.f)
                vecMax[i] = (aabb1.max[i] - aabb0.min[i]) / dir[i];
            else if (aabb0.max[i] > aabb1.min[i] && dir[i] < 0.f)
                vecMax[i] = (aabb1.min[i] - aabb0.max[i]) / dir[i];
            else if (aabb0.max[i] < aabb1.min[i] && dir[i] < 0.f)
                vecMax[i] = (aabb1.min[i] - aabb0.max[i]) / dir[i];
            else if (aabb1.max[i] < aabb0.min[i] && dir[i] > 0.f)
                vecMax[i] = (aabb1.max[i] - aabb0.min[i]) / dir[i];
        }
    }

    int maxAxis = 0;
    if (vecMin[1] > vecMin[0])
        maxAxis = 1;
    if (vecMin[2] > vecMin[maxAxis])
        maxAxis = 2;

    float minMax = std::min(std::min(vecMax[2], vecMax[1]), vecMax[0]);
    if (vecMin[maxAxis] > minMax)
        return false;
    d = minMax;

    normal = zeus::CVector3f::skZero;
    normal[maxAxis] = dir[maxAxis] > 0.f ? -1.f : 1.f;

    for (int i=0 ; i<3 ; ++i)
        point[i] = dir[i] > 0.f ? aabb0.max[i] : aabb0.min[i];

    point += float(d) * dir;
    return true;
}

}