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godot/thirdparty/bullet/BulletCollision/NarrowPhaseCollision/btMprPenetration.h

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/***
* ---------------------------------
* Copyright (c)2012 Daniel Fiser <danfis@danfis.cz>
*
* This file was ported from mpr.c file, part of libccd.
* The Minkoski Portal Refinement implementation was ported
* to OpenCL by Erwin Coumans for the Bullet 3 Physics library.
* The original MPR idea and implementation is by Gary Snethen
* in XenoCollide, see http://github.com/erwincoumans/xenocollide
*
* Distributed under the OSI-approved BSD License (the "License");
* see <http://www.opensource.org/licenses/bsd-license.php>.
* This software is distributed WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the License for more information.
*/
///2014 Oct, Erwin Coumans, Use templates to avoid void* casts
#ifndef BT_MPR_PENETRATION_H
#define BT_MPR_PENETRATION_H
#define BT_DEBUG_MPR1
#include "LinearMath/btTransform.h"
#include "LinearMath/btAlignedObjectArray.h"
//#define MPR_AVERAGE_CONTACT_POSITIONS
struct btMprCollisionDescription
{
btVector3 m_firstDir;
int m_maxGjkIterations;
btScalar m_maximumDistanceSquared;
btScalar m_gjkRelError2;
btMprCollisionDescription()
: m_firstDir(0, 1, 0),
m_maxGjkIterations(1000),
m_maximumDistanceSquared(1e30f),
m_gjkRelError2(1.0e-6)
{
}
virtual ~btMprCollisionDescription()
{
}
};
struct btMprDistanceInfo
{
btVector3 m_pointOnA;
btVector3 m_pointOnB;
btVector3 m_normalBtoA;
btScalar m_distance;
};
#ifdef __cplusplus
#define BT_MPR_SQRT sqrtf
#else
#define BT_MPR_SQRT sqrt
#endif
#define BT_MPR_FMIN(x, y) ((x) < (y) ? (x) : (y))
#define BT_MPR_FABS fabs
#define BT_MPR_TOLERANCE 1E-6f
#define BT_MPR_MAX_ITERATIONS 1000
struct _btMprSupport_t
{
btVector3 v; //!< Support point in minkowski sum
btVector3 v1; //!< Support point in obj1
btVector3 v2; //!< Support point in obj2
};
typedef struct _btMprSupport_t btMprSupport_t;
struct _btMprSimplex_t
{
btMprSupport_t ps[4];
int last; //!< index of last added point
};
typedef struct _btMprSimplex_t btMprSimplex_t;
inline btMprSupport_t *btMprSimplexPointW(btMprSimplex_t *s, int idx)
{
return &s->ps[idx];
}
inline void btMprSimplexSetSize(btMprSimplex_t *s, int size)
{
s->last = size - 1;
}
#ifdef DEBUG_MPR
inline void btPrintPortalVertex(_btMprSimplex_t *portal, int index)
{
printf("portal[%d].v = %f,%f,%f, v1=%f,%f,%f, v2=%f,%f,%f\n", index, portal->ps[index].v.x(), portal->ps[index].v.y(), portal->ps[index].v.z(),
portal->ps[index].v1.x(), portal->ps[index].v1.y(), portal->ps[index].v1.z(),
portal->ps[index].v2.x(), portal->ps[index].v2.y(), portal->ps[index].v2.z());
}
#endif //DEBUG_MPR
inline int btMprSimplexSize(const btMprSimplex_t *s)
{
return s->last + 1;
}
inline const btMprSupport_t *btMprSimplexPoint(const btMprSimplex_t *s, int idx)
{
// here is no check on boundaries
return &s->ps[idx];
}
inline void btMprSupportCopy(btMprSupport_t *d, const btMprSupport_t *s)
{
*d = *s;
}
inline void btMprSimplexSet(btMprSimplex_t *s, size_t pos, const btMprSupport_t *a)
{
btMprSupportCopy(s->ps + pos, a);
}
inline void btMprSimplexSwap(btMprSimplex_t *s, size_t pos1, size_t pos2)
{
btMprSupport_t supp;
btMprSupportCopy(&supp, &s->ps[pos1]);
btMprSupportCopy(&s->ps[pos1], &s->ps[pos2]);
btMprSupportCopy(&s->ps[pos2], &supp);
}
inline int btMprIsZero(float val)
{
return BT_MPR_FABS(val) < FLT_EPSILON;
}
inline int btMprEq(float _a, float _b)
{
float ab;
float a, b;
ab = BT_MPR_FABS(_a - _b);
if (BT_MPR_FABS(ab) < FLT_EPSILON)
return 1;
a = BT_MPR_FABS(_a);
b = BT_MPR_FABS(_b);
if (b > a)
{
return ab < FLT_EPSILON * b;
}
else
{
return ab < FLT_EPSILON * a;
}
}
inline int btMprVec3Eq(const btVector3 *a, const btVector3 *b)
{
return btMprEq((*a).x(), (*b).x()) && btMprEq((*a).y(), (*b).y()) && btMprEq((*a).z(), (*b).z());
}
template <typename btConvexTemplate>
inline void btFindOrigin(const btConvexTemplate &a, const btConvexTemplate &b, const btMprCollisionDescription &colDesc, btMprSupport_t *center)
{
center->v1 = a.getObjectCenterInWorld();
center->v2 = b.getObjectCenterInWorld();
center->v = center->v1 - center->v2;
}
inline void btMprVec3Set(btVector3 *v, float x, float y, float z)
{
v->setValue(x, y, z);
}
inline void btMprVec3Add(btVector3 *v, const btVector3 *w)
{
*v += *w;
}
inline void btMprVec3Copy(btVector3 *v, const btVector3 *w)
{
*v = *w;
}
inline void btMprVec3Scale(btVector3 *d, float k)
{
*d *= k;
}
inline float btMprVec3Dot(const btVector3 *a, const btVector3 *b)
{
float dot;
dot = btDot(*a, *b);
return dot;
}
inline float btMprVec3Len2(const btVector3 *v)
{
return btMprVec3Dot(v, v);
}
inline void btMprVec3Normalize(btVector3 *d)
{
float k = 1.f / BT_MPR_SQRT(btMprVec3Len2(d));
btMprVec3Scale(d, k);
}
inline void btMprVec3Cross(btVector3 *d, const btVector3 *a, const btVector3 *b)
{
*d = btCross(*a, *b);
}
inline void btMprVec3Sub2(btVector3 *d, const btVector3 *v, const btVector3 *w)
{
*d = *v - *w;
}
inline void btPortalDir(const btMprSimplex_t *portal, btVector3 *dir)
{
btVector3 v2v1, v3v1;
btMprVec3Sub2(&v2v1, &btMprSimplexPoint(portal, 2)->v,
&btMprSimplexPoint(portal, 1)->v);
btMprVec3Sub2(&v3v1, &btMprSimplexPoint(portal, 3)->v,
&btMprSimplexPoint(portal, 1)->v);
btMprVec3Cross(dir, &v2v1, &v3v1);
btMprVec3Normalize(dir);
}
inline int portalEncapsulesOrigin(const btMprSimplex_t *portal,
const btVector3 *dir)
{
float dot;
dot = btMprVec3Dot(dir, &btMprSimplexPoint(portal, 1)->v);
return btMprIsZero(dot) || dot > 0.f;
}
inline int portalReachTolerance(const btMprSimplex_t *portal,
const btMprSupport_t *v4,
const btVector3 *dir)
{
float dv1, dv2, dv3, dv4;
float dot1, dot2, dot3;
// find the smallest dot product of dir and {v1-v4, v2-v4, v3-v4}
dv1 = btMprVec3Dot(&btMprSimplexPoint(portal, 1)->v, dir);
dv2 = btMprVec3Dot(&btMprSimplexPoint(portal, 2)->v, dir);
dv3 = btMprVec3Dot(&btMprSimplexPoint(portal, 3)->v, dir);
dv4 = btMprVec3Dot(&v4->v, dir);
dot1 = dv4 - dv1;
dot2 = dv4 - dv2;
dot3 = dv4 - dv3;
dot1 = BT_MPR_FMIN(dot1, dot2);
dot1 = BT_MPR_FMIN(dot1, dot3);
return btMprEq(dot1, BT_MPR_TOLERANCE) || dot1 < BT_MPR_TOLERANCE;
}
inline int portalCanEncapsuleOrigin(const btMprSimplex_t *portal,
const btMprSupport_t *v4,
const btVector3 *dir)
{
float dot;
dot = btMprVec3Dot(&v4->v, dir);
return btMprIsZero(dot) || dot > 0.f;
}
inline void btExpandPortal(btMprSimplex_t *portal,
const btMprSupport_t *v4)
{
float dot;
btVector3 v4v0;
btMprVec3Cross(&v4v0, &v4->v, &btMprSimplexPoint(portal, 0)->v);
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 1)->v, &v4v0);
if (dot > 0.f)
{
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 2)->v, &v4v0);
if (dot > 0.f)
{
btMprSimplexSet(portal, 1, v4);
}
else
{
btMprSimplexSet(portal, 3, v4);
}
}
else
{
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 3)->v, &v4v0);
if (dot > 0.f)
{
btMprSimplexSet(portal, 2, v4);
}
else
{
btMprSimplexSet(portal, 1, v4);
}
}
}
template <typename btConvexTemplate>
inline void btMprSupport(const btConvexTemplate &a, const btConvexTemplate &b,
const btMprCollisionDescription &colDesc,
const btVector3 &dir, btMprSupport_t *supp)
{
btVector3 separatingAxisInA = dir * a.getWorldTransform().getBasis();
btVector3 separatingAxisInB = -dir * b.getWorldTransform().getBasis();
btVector3 pInA = a.getLocalSupportWithMargin(separatingAxisInA);
btVector3 qInB = b.getLocalSupportWithMargin(separatingAxisInB);
supp->v1 = a.getWorldTransform()(pInA);
supp->v2 = b.getWorldTransform()(qInB);
supp->v = supp->v1 - supp->v2;
}
template <typename btConvexTemplate>
static int btDiscoverPortal(const btConvexTemplate &a, const btConvexTemplate &b,
const btMprCollisionDescription &colDesc,
btMprSimplex_t *portal)
{
btVector3 dir, va, vb;
float dot;
int cont;
// vertex 0 is center of portal
btFindOrigin(a, b, colDesc, btMprSimplexPointW(portal, 0));
// vertex 0 is center of portal
btMprSimplexSetSize(portal, 1);
btVector3 zero = btVector3(0, 0, 0);
btVector3 *org = &zero;
if (btMprVec3Eq(&btMprSimplexPoint(portal, 0)->v, org))
{
// Portal's center lies on origin (0,0,0) => we know that objects
// intersect but we would need to know penetration info.
// So move center little bit...
btMprVec3Set(&va, FLT_EPSILON * 10.f, 0.f, 0.f);
btMprVec3Add(&btMprSimplexPointW(portal, 0)->v, &va);
}
// vertex 1 = support in direction of origin
btMprVec3Copy(&dir, &btMprSimplexPoint(portal, 0)->v);
btMprVec3Scale(&dir, -1.f);
btMprVec3Normalize(&dir);
btMprSupport(a, b, colDesc, dir, btMprSimplexPointW(portal, 1));
btMprSimplexSetSize(portal, 2);
// test if origin isn't outside of v1
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 1)->v, &dir);
if (btMprIsZero(dot) || dot < 0.f)
return -1;
// vertex 2
btMprVec3Cross(&dir, &btMprSimplexPoint(portal, 0)->v,
&btMprSimplexPoint(portal, 1)->v);
if (btMprIsZero(btMprVec3Len2(&dir)))
{
if (btMprVec3Eq(&btMprSimplexPoint(portal, 1)->v, org))
{
// origin lies on v1
return 1;
}
else
{
// origin lies on v0-v1 segment
return 2;
}
}
btMprVec3Normalize(&dir);
btMprSupport(a, b, colDesc, dir, btMprSimplexPointW(portal, 2));
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 2)->v, &dir);
if (btMprIsZero(dot) || dot < 0.f)
return -1;
btMprSimplexSetSize(portal, 3);
// vertex 3 direction
btMprVec3Sub2(&va, &btMprSimplexPoint(portal, 1)->v,
&btMprSimplexPoint(portal, 0)->v);
btMprVec3Sub2(&vb, &btMprSimplexPoint(portal, 2)->v,
&btMprSimplexPoint(portal, 0)->v);
btMprVec3Cross(&dir, &va, &vb);
btMprVec3Normalize(&dir);
// it is better to form portal faces to be oriented "outside" origin
dot = btMprVec3Dot(&dir, &btMprSimplexPoint(portal, 0)->v);
if (dot > 0.f)
{
btMprSimplexSwap(portal, 1, 2);
btMprVec3Scale(&dir, -1.f);
}
while (btMprSimplexSize(portal) < 4)
{
btMprSupport(a, b, colDesc, dir, btMprSimplexPointW(portal, 3));
dot = btMprVec3Dot(&btMprSimplexPoint(portal, 3)->v, &dir);
if (btMprIsZero(dot) || dot < 0.f)
return -1;
cont = 0;
// test if origin is outside (v1, v0, v3) - set v2 as v3 and
// continue
btMprVec3Cross(&va, &btMprSimplexPoint(portal, 1)->v,
&btMprSimplexPoint(portal, 3)->v);
dot = btMprVec3Dot(&va, &btMprSimplexPoint(portal, 0)->v);
if (dot < 0.f && !btMprIsZero(dot))
{
btMprSimplexSet(portal, 2, btMprSimplexPoint(portal, 3));
cont = 1;
}
if (!cont)
{
// test if origin is outside (v3, v0, v2) - set v1 as v3 and
// continue
btMprVec3Cross(&va, &btMprSimplexPoint(portal, 3)->v,
&btMprSimplexPoint(portal, 2)->v);
dot = btMprVec3Dot(&va, &btMprSimplexPoint(portal, 0)->v);
if (dot < 0.f && !btMprIsZero(dot))
{
btMprSimplexSet(portal, 1, btMprSimplexPoint(portal, 3));
cont = 1;
}
}
if (cont)
{
btMprVec3Sub2(&va, &btMprSimplexPoint(portal, 1)->v,
&btMprSimplexPoint(portal, 0)->v);
btMprVec3Sub2(&vb, &btMprSimplexPoint(portal, 2)->v,
&btMprSimplexPoint(portal, 0)->v);
btMprVec3Cross(&dir, &va, &vb);
btMprVec3Normalize(&dir);
}
else
{
btMprSimplexSetSize(portal, 4);
}
}
return 0;
}
template <typename btConvexTemplate>
static int btRefinePortal(const btConvexTemplate &a, const btConvexTemplate &b, const btMprCollisionDescription &colDesc,
btMprSimplex_t *portal)
{
btVector3 dir;
btMprSupport_t v4;
for (int i = 0; i < BT_MPR_MAX_ITERATIONS; i++)
//while (1)
{
// compute direction outside the portal (from v0 through v1,v2,v3
// face)
btPortalDir(portal, &dir);
// test if origin is inside the portal
if (portalEncapsulesOrigin(portal, &dir))
return 0;
// get next support point
btMprSupport(a, b, colDesc, dir, &v4);
// test if v4 can expand portal to contain origin and if portal
// expanding doesn't reach given tolerance
if (!portalCanEncapsuleOrigin(portal, &v4, &dir) || portalReachTolerance(portal, &v4, &dir))
{
return -1;
}
// v1-v2-v3 triangle must be rearranged to face outside Minkowski
// difference (direction from v0).
btExpandPortal(portal, &v4);
}
return -1;
}
static void btFindPos(const btMprSimplex_t *portal, btVector3 *pos)
{
btVector3 zero = btVector3(0, 0, 0);
btVector3 *origin = &zero;
btVector3 dir;
size_t i;
float b[4], sum, inv;
btVector3 vec, p1, p2;
btPortalDir(portal, &dir);
// use barycentric coordinates of tetrahedron to find origin
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 1)->v,
&btMprSimplexPoint(portal, 2)->v);
b[0] = btMprVec3Dot(&vec, &btMprSimplexPoint(portal, 3)->v);
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 3)->v,
&btMprSimplexPoint(portal, 2)->v);
b[1] = btMprVec3Dot(&vec, &btMprSimplexPoint(portal, 0)->v);
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 0)->v,
&btMprSimplexPoint(portal, 1)->v);
b[2] = btMprVec3Dot(&vec, &btMprSimplexPoint(portal, 3)->v);
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 2)->v,
&btMprSimplexPoint(portal, 1)->v);
b[3] = btMprVec3Dot(&vec, &btMprSimplexPoint(portal, 0)->v);
sum = b[0] + b[1] + b[2] + b[3];
if (btMprIsZero(sum) || sum < 0.f)
{
b[0] = 0.f;
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 2)->v,
&btMprSimplexPoint(portal, 3)->v);
b[1] = btMprVec3Dot(&vec, &dir);
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 3)->v,
&btMprSimplexPoint(portal, 1)->v);
b[2] = btMprVec3Dot(&vec, &dir);
btMprVec3Cross(&vec, &btMprSimplexPoint(portal, 1)->v,
&btMprSimplexPoint(portal, 2)->v);
b[3] = btMprVec3Dot(&vec, &dir);
sum = b[1] + b[2] + b[3];
}
inv = 1.f / sum;
btMprVec3Copy(&p1, origin);
btMprVec3Copy(&p2, origin);
for (i = 0; i < 4; i++)
{
btMprVec3Copy(&vec, &btMprSimplexPoint(portal, i)->v1);
btMprVec3Scale(&vec, b[i]);
btMprVec3Add(&p1, &vec);
btMprVec3Copy(&vec, &btMprSimplexPoint(portal, i)->v2);
btMprVec3Scale(&vec, b[i]);
btMprVec3Add(&p2, &vec);
}
btMprVec3Scale(&p1, inv);
btMprVec3Scale(&p2, inv);
#ifdef MPR_AVERAGE_CONTACT_POSITIONS
btMprVec3Copy(pos, &p1);
btMprVec3Add(pos, &p2);
btMprVec3Scale(pos, 0.5);
#else
btMprVec3Copy(pos, &p2);
#endif //MPR_AVERAGE_CONTACT_POSITIONS
}
inline float btMprVec3Dist2(const btVector3 *a, const btVector3 *b)
{
btVector3 ab;
btMprVec3Sub2(&ab, a, b);
return btMprVec3Len2(&ab);
}
inline float _btMprVec3PointSegmentDist2(const btVector3 *P,
const btVector3 *x0,
const btVector3 *b,
btVector3 *witness)
{
// The computation comes from solving equation of segment:
// S(t) = x0 + t.d
// where - x0 is initial point of segment
// - d is direction of segment from x0 (|d| > 0)
// - t belongs to <0, 1> interval
//
// Than, distance from a segment to some point P can be expressed:
// D(t) = |x0 + t.d - P|^2
// which is distance from any point on segment. Minimization
// of this function brings distance from P to segment.
// Minimization of D(t) leads to simple quadratic equation that's
// solving is straightforward.
//
// Bonus of this method is witness point for free.
float dist, t;
btVector3 d, a;
// direction of segment
btMprVec3Sub2(&d, b, x0);
// precompute vector from P to x0
btMprVec3Sub2(&a, x0, P);
t = -1.f * btMprVec3Dot(&a, &d);
t /= btMprVec3Len2(&d);
if (t < 0.f || btMprIsZero(t))
{
dist = btMprVec3Dist2(x0, P);
if (witness)
btMprVec3Copy(witness, x0);
}
else if (t > 1.f || btMprEq(t, 1.f))
{
dist = btMprVec3Dist2(b, P);
if (witness)
btMprVec3Copy(witness, b);
}
else
{
if (witness)
{
btMprVec3Copy(witness, &d);
btMprVec3Scale(witness, t);
btMprVec3Add(witness, x0);
dist = btMprVec3Dist2(witness, P);
}
else
{
// recycling variables
btMprVec3Scale(&d, t);
btMprVec3Add(&d, &a);
dist = btMprVec3Len2(&d);
}
}
return dist;
}
inline float btMprVec3PointTriDist2(const btVector3 *P,
const btVector3 *x0, const btVector3 *B,
const btVector3 *C,
btVector3 *witness)
{
// Computation comes from analytic expression for triangle (x0, B, C)
// T(s, t) = x0 + s.d1 + t.d2, where d1 = B - x0 and d2 = C - x0 and
// Then equation for distance is:
// D(s, t) = | T(s, t) - P |^2
// This leads to minimization of quadratic function of two variables.
// The solution from is taken only if s is between 0 and 1, t is
// between 0 and 1 and t + s < 1, otherwise distance from segment is
// computed.
btVector3 d1, d2, a;
float u, v, w, p, q, r;
float s, t, dist, dist2;
btVector3 witness2;
btMprVec3Sub2(&d1, B, x0);
btMprVec3Sub2(&d2, C, x0);
btMprVec3Sub2(&a, x0, P);
u = btMprVec3Dot(&a, &a);
v = btMprVec3Dot(&d1, &d1);
w = btMprVec3Dot(&d2, &d2);
p = btMprVec3Dot(&a, &d1);
q = btMprVec3Dot(&a, &d2);
r = btMprVec3Dot(&d1, &d2);
btScalar div = (w * v - r * r);
if (btMprIsZero(div))
{
s = -1;
}
else
{
s = (q * r - w * p) / div;
t = (-s * r - q) / w;
}
if ((btMprIsZero(s) || s > 0.f) && (btMprEq(s, 1.f) || s < 1.f) && (btMprIsZero(t) || t > 0.f) && (btMprEq(t, 1.f) || t < 1.f) && (btMprEq(t + s, 1.f) || t + s < 1.f))
{
if (witness)
{
btMprVec3Scale(&d1, s);
btMprVec3Scale(&d2, t);
btMprVec3Copy(witness, x0);
btMprVec3Add(witness, &d1);
btMprVec3Add(witness, &d2);
dist = btMprVec3Dist2(witness, P);
}
else
{
dist = s * s * v;
dist += t * t * w;
dist += 2.f * s * t * r;
dist += 2.f * s * p;
dist += 2.f * t * q;
dist += u;
}
}
else
{
dist = _btMprVec3PointSegmentDist2(P, x0, B, witness);
dist2 = _btMprVec3PointSegmentDist2(P, x0, C, &witness2);
if (dist2 < dist)
{
dist = dist2;
if (witness)
btMprVec3Copy(witness, &witness2);
}
dist2 = _btMprVec3PointSegmentDist2(P, B, C, &witness2);
if (dist2 < dist)
{
dist = dist2;
if (witness)
btMprVec3Copy(witness, &witness2);
}
}
return dist;
}
template <typename btConvexTemplate>
static void btFindPenetr(const btConvexTemplate &a, const btConvexTemplate &b,
const btMprCollisionDescription &colDesc,
btMprSimplex_t *portal,
float *depth, btVector3 *pdir, btVector3 *pos)
{
btVector3 dir;
btMprSupport_t v4;
unsigned long iterations;
btVector3 zero = btVector3(0, 0, 0);
btVector3 *origin = &zero;
iterations = 1UL;
for (int i = 0; i < BT_MPR_MAX_ITERATIONS; i++)
//while (1)
{
// compute portal direction and obtain next support point
btPortalDir(portal, &dir);
btMprSupport(a, b, colDesc, dir, &v4);
// reached tolerance -> find penetration info
if (portalReachTolerance(portal, &v4, &dir) || iterations == BT_MPR_MAX_ITERATIONS)
{
*depth = btMprVec3PointTriDist2(origin, &btMprSimplexPoint(portal, 1)->v, &btMprSimplexPoint(portal, 2)->v, &btMprSimplexPoint(portal, 3)->v, pdir);
*depth = BT_MPR_SQRT(*depth);
if (btMprIsZero((*pdir).x()) && btMprIsZero((*pdir).y()) && btMprIsZero((*pdir).z()))
{
*pdir = dir;
}
btMprVec3Normalize(pdir);
// barycentric coordinates:
btFindPos(portal, pos);
return;
}
btExpandPortal(portal, &v4);
iterations++;
}
}
static void btFindPenetrTouch(btMprSimplex_t *portal, float *depth, btVector3 *dir, btVector3 *pos)
{
// Touching contact on portal's v1 - so depth is zero and direction
// is unimportant and pos can be guessed
*depth = 0.f;
btVector3 zero = btVector3(0, 0, 0);
btVector3 *origin = &zero;
btMprVec3Copy(dir, origin);
#ifdef MPR_AVERAGE_CONTACT_POSITIONS
btMprVec3Copy(pos, &btMprSimplexPoint(portal, 1)->v1);
btMprVec3Add(pos, &btMprSimplexPoint(portal, 1)->v2);
btMprVec3Scale(pos, 0.5);
#else
btMprVec3Copy(pos, &btMprSimplexPoint(portal, 1)->v2);
#endif
}
static void btFindPenetrSegment(btMprSimplex_t *portal,
float *depth, btVector3 *dir, btVector3 *pos)
{
// Origin lies on v0-v1 segment.
// Depth is distance to v1, direction also and position must be
// computed
#ifdef MPR_AVERAGE_CONTACT_POSITIONS
btMprVec3Copy(pos, &btMprSimplexPoint(portal, 1)->v1);
btMprVec3Add(pos, &btMprSimplexPoint(portal, 1)->v2);
btMprVec3Scale(pos, 0.5f);
#else
btMprVec3Copy(pos, &btMprSimplexPoint(portal, 1)->v2);
#endif //MPR_AVERAGE_CONTACT_POSITIONS
btMprVec3Copy(dir, &btMprSimplexPoint(portal, 1)->v);
*depth = BT_MPR_SQRT(btMprVec3Len2(dir));
btMprVec3Normalize(dir);
}
template <typename btConvexTemplate>
inline int btMprPenetration(const btConvexTemplate &a, const btConvexTemplate &b,
const btMprCollisionDescription &colDesc,
float *depthOut, btVector3 *dirOut, btVector3 *posOut)
{
btMprSimplex_t portal;
// Phase 1: Portal discovery
int result = btDiscoverPortal(a, b, colDesc, &portal);
//sepAxis[pairIndex] = *pdir;//or -dir?
switch (result)
{
case 0:
{
// Phase 2: Portal refinement
result = btRefinePortal(a, b, colDesc, &portal);
if (result < 0)
return -1;
// Phase 3. Penetration info
btFindPenetr(a, b, colDesc, &portal, depthOut, dirOut, posOut);
break;
}
case 1:
{
// Touching contact on portal's v1.
btFindPenetrTouch(&portal, depthOut, dirOut, posOut);
result = 0;
break;
}
case 2:
{
btFindPenetrSegment(&portal, depthOut, dirOut, posOut);
result = 0;
break;
}
default:
{
//if (res < 0)
//{
// Origin isn't inside portal - no collision.
result = -1;
//}
}
};
return result;
};
template <typename btConvexTemplate, typename btMprDistanceTemplate>
inline int btComputeMprPenetration(const btConvexTemplate &a, const btConvexTemplate &b, const btMprCollisionDescription &colDesc, btMprDistanceTemplate *distInfo)
{
btVector3 dir, pos;
float depth;
int res = btMprPenetration(a, b, colDesc, &depth, &dir, &pos);
if (res == 0)
{
distInfo->m_distance = -depth;
distInfo->m_pointOnB = pos;
distInfo->m_normalBtoA = -dir;
distInfo->m_pointOnA = pos - distInfo->m_distance * dir;
return 0;
}
return -1;
}
#endif //BT_MPR_PENETRATION_H
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