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CollisionHandler.cpp
775 lines (645 loc) · 23.6 KB
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CollisionHandler.cpp
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/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
#include "CollisionHandler.h"
#include "CollisionVolume.h"
#include "Map/ReadMap.h"
#include "Rendering/Models/3DModel.h"
#include "Sim/Units/Unit.h"
#include "Sim/Features/Feature.h"
#include "Sim/Misc/GroundBlockingObjectMap.h"
#include "Sim/Misc/GlobalConstants.h"
#include "System/FastMath.h"
#include "System/Matrix44f.h"
#include "System/Log/ILog.h"
unsigned int CCollisionHandler::numDiscTests = 0;
unsigned int CCollisionHandler::numContTests = 0;
void CCollisionHandler::PrintStats()
{
LOG("[CCollisionHandler] dis-/continuous tests: %i/%i", numDiscTests, numContTests);
}
bool CCollisionHandler::DetectHit(const CSolidObject* o, const float3 p0, const float3 p1, CollisionQuery* cq, bool forceTrace)
{
return (DetectHit(o->collisionVolume, o, p0, p1, cq, forceTrace));
}
bool CCollisionHandler::DetectHit(const CollisionVolume* v, const CSolidObject* o, const float3 p0, const float3 p1, CollisionQuery* cq, bool forceTrace)
{
bool hit = false;
if (cq != NULL)
cq->Reset();
if (o->IsInVoid())
return hit;
// test *only* for ray intersections with the piece tree
// (whether or not the unit's regular volume is disabled)
//
// overrides forceTrace, which itself overrides testType
// needs a unit because only units have a LocalModel atm
//
// NOTE:
// usePieceCollisionVolumes is parsed in SolidObjectDef
// so features *can* also set it, which will crash here
// (prevented by FeatureHandler)
if (v->DefaultToPieceTree())
return (CCollisionHandler::IntersectPieceTree(static_cast<const CUnit*>(o), p0, p1, cq));
if (v->IgnoreHits())
return hit;
if (forceTrace || v->UseContHitTest()) {
hit = CCollisionHandler::Intersect(v, o, p0, p1, cq);
} else {
// Collision() does not need p1 (no ray, no ray-endpoint)
hit = CCollisionHandler::Collision(v, o, p0, cq);
}
return hit;
}
bool CCollisionHandler::Collision(const CollisionVolume* v, const CSolidObject* o, const float3 p, CollisionQuery* cq)
{
bool hit = false;
// if <v> is a sphere, then the bounding radius is just its own radius -->
// we do not need to test the COLVOL_TYPE_SPHERE case again when this fails
if ((v->GetWorldSpacePos(o) - p).SqLength() > v->GetBoundingRadiusSq())
return hit;
if (v->DefaultToFootPrint()) {
hit = CCollisionHandler::CollisionFootPrint(o, p);
} else {
switch (v->GetVolumeType()) {
case CollisionVolume::COLVOL_TYPE_SPHERE: {
hit = true;
} break;
default: {
// NOTE: we have to translate by relMidPos to get to midPos
// (which is where the collision volume gets drawn) because
// GetTransformMatrix() only uses pos (UNITS AND FEATURES)
CMatrix44f m = o->GetTransformMatrix(true);
m.Translate(o->relMidPos * WORLD_TO_OBJECT_SPACE);
m.Translate(v->GetOffsets());
hit = CCollisionHandler::Collision(v, m, p);
}
}
}
if (cq != NULL && hit) {
// same as the special cases for the continuous tests
// (but here p is a valid coordinate and safe to use)
cq->b0 = CQ_POINT_IN_VOL; cq->t0 = 0.0f; cq->p0 = p;
}
return hit;
}
bool CCollisionHandler::CollisionFootPrint(const CSolidObject* o, const float3& p)
{
// If the object isn't marked on blocking map, or if it is flying,
// effecively only the early-out sphere check (in Collision(CUnit*)
// or Collision(CFeature*)) is performed (which we already passed).
if (!o->IsBlocking())
return false;
if (o->IsInAir())
return false;
// this is semi-equivalent to testing if <p> is inside the rectangular
// collision volume in the COLVOL_TYPE_BOX case, but takes non-blocking
// yardmap squares into account (even though this is a discrete test so
// projectile might have tunneled across blocking squares to get to <p>)
// note: if we get here <v> is always a box
const float invSquareSize = 1.0f / SQUARE_SIZE;
const int squareIdx = int(p.x * invSquareSize) + int(p.z * invSquareSize) * mapDims.mapx;
if (squareIdx < 0 || squareIdx >= mapDims.mapSquares)
return false;
const BlockingMapCell& cell = groundBlockingObjectMap->GetCell(squareIdx);
return (cell.find(o->GetBlockingMapID()) != cell.end());
}
bool CCollisionHandler::Collision(const CollisionVolume* v, const CMatrix44f& m, const float3& p)
{
numDiscTests += 1;
// get the inverse volume transformation matrix and
// apply it to the projectile's position, then test
// if the transformed position lies within the axis-
// aligned collision volume
CMatrix44f mInv = m.Invert();
float3 pi = mInv.Mul(p);
bool hit = false;
switch (v->GetVolumeType()) {
case CollisionVolume::COLVOL_TYPE_SPHERE: {
// normally, this code is never executed, because the higher level
// Collision(CFeature*) and Collision(CUnit*) already optimize via
// early-out tests
hit = (pi.dot(pi) <= v->GetHSqScales().x);
// test for arbitrary ellipsoids (no longer supported)
// const float f1 = (pi.x * pi.x) / v->GetHSqScales().x;
// const float f2 = (pi.y * pi.y) / v->GetHSqScales().y;
// const float f3 = (pi.z * pi.z) / v->GetHSqScales().z;
// hit = ((f1 + f2 + f3) <= 1.0f);
} break;
case CollisionVolume::COLVOL_TYPE_CYLINDER: {
switch (v->GetPrimaryAxis()) {
case CollisionVolume::COLVOL_AXIS_X: {
const bool xPass = (math::fabs(pi.x) < v->GetHScales().x);
const float yRat = (pi.y * pi.y) / v->GetHSqScales().y;
const float zRat = (pi.z * pi.z) / v->GetHSqScales().z;
hit = (xPass && (yRat + zRat <= 1.0f));
} break;
case CollisionVolume::COLVOL_AXIS_Y: {
const bool yPass = (math::fabs(pi.y) < v->GetHScales().y);
const float xRat = (pi.x * pi.x) / v->GetHSqScales().x;
const float zRat = (pi.z * pi.z) / v->GetHSqScales().z;
hit = (yPass && (xRat + zRat <= 1.0f));
} break;
case CollisionVolume::COLVOL_AXIS_Z: {
const bool zPass = (math::fabs(pi.z) < v->GetHScales().z);
const float xRat = (pi.x * pi.x) / v->GetHSqScales().x;
const float yRat = (pi.y * pi.y) / v->GetHSqScales().y;
hit = (zPass && (xRat + yRat <= 1.0f));
} break;
}
} break;
case CollisionVolume::COLVOL_TYPE_BOX: {
const bool b1 = (math::fabs(pi.x) < v->GetHScales().x);
const bool b2 = (math::fabs(pi.y) < v->GetHScales().y);
const bool b3 = (math::fabs(pi.z) < v->GetHScales().z);
hit = (b1 && b2 && b3);
} break;
}
return hit;
}
bool CCollisionHandler::MouseHit(const CUnit* u, const float3& p0, const float3& p1, const CollisionVolume* v, CollisionQuery* cq)
{
if (cq != NULL)
cq->Reset();
if (!u->IsInVoid()) {
if (v->DefaultToPieceTree()) {
return (CCollisionHandler::IntersectPieceTree(u, p0, p1, cq));
}
if (!v->IgnoreHits()) {
// note: should mouse-rays care about
// IgnoreHits if unit is not in void?
CMatrix44f m = u->GetTransformMatrix(false, true);
m.Translate(u->relMidPos * WORLD_TO_OBJECT_SPACE);
m.Translate(v->GetOffsets());
return (CCollisionHandler::Intersect(v, m, p0, p1, cq));
}
}
return false;
}
/*
bool CCollisionHandler::IntersectPieceTreeHelper(
LocalModelPiece* lmp,
const CMatrix44f& mat,
const float3& p0,
const float3& p1,
std::vector<CollisionQuery>* cqs
) {
bool ret = false;
CollisionVolume* lmpVol = lmp->GetCollisionVolume();
CMatrix44f volMat = lmp->GetModelSpaceMatrix() * mat;
if (lmp->scriptSetVisible && !lmpVol->IgnoreHits()) {
volMat.Translate(lmpVol->GetOffsets());
CollisionQuery cq;
if ((ret = CCollisionHandler::Intersect(lmpVol, volMat, p0, p1, &cq))) {
cq.SetHitPiece(lmp); cqs->push_back(cq);
}
volMat.Translate(-lmpVol->GetOffsets());
}
for (unsigned int i = 0; i < lmp->children.size(); i++) {
ret |= IntersectPieceTreeHelper(lmp->children[i], mat, p0, p1, cqs);
}
return ret;
}
*/
bool CCollisionHandler::IntersectPiecesHelper(
const CUnit* u,
const float3& p0,
const float3& p1,
CollisionQuery* cq
) {
CMatrix44f unitMat = u->GetTransformMatrix(true);
CMatrix44f volMat;
float minDistSq = std::numeric_limits<float>::max();
for (unsigned int n = 0; n < u->localModel->pieces.size(); n++) {
LocalModelPiece* lmp = u->localModel->GetPiece(n);
const CollisionVolume* lmpVol = lmp->GetCollisionVolume();
if (!lmp->scriptSetVisible || lmpVol->IgnoreHits())
continue;
volMat = unitMat * lmp->GetModelSpaceMatrix();
volMat.Translate(lmpVol->GetOffsets());
CollisionQuery cqn;
if (!CCollisionHandler::Intersect(lmpVol, volMat, p0, p1, &cqn))
continue;
// skip if neither an ingress nor an egress hit
if (!cqn.AnyHit())
continue;
// save the closest intersection (others are not needed)
if (cqn.GetHitPos().SqDistance(p0) >= minDistSq)
continue;
minDistSq = cqn.GetHitPos().SqDistance(p0);
if (cq != nullptr) {
*cq = cqn;
cq->SetHitPiece(lmp);
} else {
return true;
}
}
// true iff at least one piece was intersected
// (query must have been reset by calling code)
return (cq != nullptr) ? (cq->GetHitPiece() != nullptr) : false;
}
bool CCollisionHandler::IntersectPieceTree(const CUnit* u, const float3& p0, const float3& p1, CollisionQuery* cq)
{
// TODO:
// needs an early-out test, but gets complicated because
// pieces can move --> no clearly defined bounding volume
return (IntersectPiecesHelper(u, p0, p1, cq));
}
inline bool CCollisionHandler::Intersect(const CollisionVolume* v, const CSolidObject* o, const float3 p0, const float3 p1, CollisionQuery* cq)
{
CMatrix44f m = o->GetTransformMatrix(true);
m.Translate(o->relMidPos * WORLD_TO_OBJECT_SPACE);
m.Translate(v->GetOffsets());
return (CCollisionHandler::Intersect(v, m, p0, p1, cq));
}
/*
bool CCollisionHandler::IntersectAlt(const collisionVolume* d, const CMatrix44f& m, const float3& p0, const float3& p1, CollisionQuery*)
{
// alternative numerical integration method (unused)
const float delta = 1.0f;
const float length = (p1 - p0).Length();
const float3 dir = (p1 - p0).Normalize();
for (float t = 0.0f; t <= length; t += delta) {
if (::Collision(d, m, p0 + dir * t)) return true;
}
return false;
}
*/
bool CCollisionHandler::Intersect(const CollisionVolume* v, const CMatrix44f& m, const float3& p0, const float3& p1, CollisionQuery* q)
{
numContTests += 1;
CMatrix44f mInv = m.Invert();
const float3 pi0 = mInv.Mul(p0);
const float3 pi1 = mInv.Mul(p1);
bool intersect = false;
// minimum and maximum (x, y, z) coordinates of transformed ray
const float rminx = std::min(pi0.x, pi1.x), rminy = std::min(pi0.y, pi1.y), rminz = std::min(pi0.z, pi1.z);
const float rmaxx = std::max(pi0.x, pi1.x), rmaxy = std::max(pi0.y, pi1.y), rmaxz = std::max(pi0.z, pi1.z);
// minimum and maximum (x, y, z) coordinates of (bounding box around) volume
const float vminx = -v->GetHScales().x, vminy = -v->GetHScales().y, vminz = -v->GetHScales().z;
const float vmaxx = v->GetHScales().x, vmaxy = v->GetHScales().y, vmaxz = v->GetHScales().z;
// check if ray segment misses (bounding box around) volume
// (if so, then no further intersection tests are necessary)
if (rmaxx < vminx || rminx > vmaxx) { return false; }
if (rmaxy < vminy || rminy > vmaxy) { return false; }
if (rmaxz < vminz || rminz > vmaxz) { return false; }
switch (v->GetVolumeType()) {
case CollisionVolume::COLVOL_TYPE_SPHERE: {
// sphere is special case of ellipsoid, reuse code
intersect = CCollisionHandler::IntersectEllipsoid(v, pi0, pi1, q);
} break;
case CollisionVolume::COLVOL_TYPE_CYLINDER: {
intersect = CCollisionHandler::IntersectCylinder(v, pi0, pi1, q);
} break;
case CollisionVolume::COLVOL_TYPE_BOX: {
// also covers footprints, but without taking the blocking-map into account
// TODO: this would require stepping ray across non-blocking yardmap squares?
//
// intersect = CCollisionHandler::IntersectFootPrint(v, pi0, pi1, q);
intersect = CCollisionHandler::IntersectBox(v, pi0, pi1, q);
} break;
}
if (q != NULL) {
// transform intersection points (iff not a special
// case, otherwise calling code should not use them)
if (q->b0 == CQ_POINT_ON_RAY) { q->p0 = m.Mul(q->p0); }
if (q->b1 == CQ_POINT_ON_RAY) { q->p1 = m.Mul(q->p1); }
}
return intersect;
}
bool CCollisionHandler::IntersectEllipsoid(const CollisionVolume* v, const float3& pi0, const float3& pi1, CollisionQuery* q)
{
// transform the volume-space points into (unit) sphere-space (requires fewer
// float-ops than solving the surface equation for arbitrary ellipsoid volumes)
const float3 pii0 = float3(pi0.x * v->GetHIScales().x, pi0.y * v->GetHIScales().y, pi0.z * v->GetHIScales().z);
const float3 pii1 = float3(pi1.x * v->GetHIScales().x, pi1.y * v->GetHIScales().y, pi1.z * v->GetHIScales().z);
const float rSq = 1.0f;
if (pii0.dot(pii0) <= rSq) {
if (q != NULL) {
// terminate early in the special case
// that ray-segment originated *in* <v>
// (these points are NOT transformed!)
q->b0 = CQ_POINT_IN_VOL; q->p0 = ZeroVector;
q->b1 = CQ_POINT_IN_VOL; q->p1 = ZeroVector;
}
return true;
}
// get the ray direction in unit-sphere space
const float3 dir = (pii1 - pii0).SafeNormalize();
// solves [ x^2 + y^2 + z^2 == r^2 ] for t
// (<A> represents dir.dot(dir), equal to 1
// since ray direction already normalized)
const float A = 1.0f;
const float B = 2.0f * (pii0).dot(dir);
const float C = pii0.dot(pii0) - rSq;
const float D = (B * B) - (4.0f * A * C);
if (D < -COLLISION_VOLUME_EPS) {
return false;
} else {
// get the length of the ray segment in volume-space
const float segLenSq = (pi1 - pi0).SqLength();
if (D < COLLISION_VOLUME_EPS) {
// one solution for t
const float t0 = -B * 0.5f;
// const float t0 = -B / (2.0f * A);
// get the intersection point in sphere-space
const float3 pTmp = pii0 + (dir * t0);
// get the intersection point in volume-space
const float3 p0 = pTmp * v->GetHScales();
// get the distance from the start of the segment
// to the intersection point in volume-space
const float dSq0 = (p0 - pi0).SqLength();
// if the intersection point is closer to p0 than
// the end of the ray segment, the hit is valid
const int b0 = (t0 > 0.0f && dSq0 <= segLenSq) * CQ_POINT_ON_RAY;
if (q != NULL) {
q->b0 = b0; q->b1 = CQ_POINT_NO_INT;
q->t0 = t0; q->t1 = 0.0f;
q->p0 = p0; q->p1 = ZeroVector;
}
return (b0 == CQ_POINT_ON_RAY);
} else {
// two solutions for t
const float rD = fastmath::apxsqrt(D);
const float t0 = (-B - rD) * 0.5f;
const float t1 = (-B + rD) * 0.5f;
// const float t0 = (-B + rD) / (2.0f * A);
// const float t1 = (-B - rD) / (2.0f * A);
// get the intersection points in sphere-space
const float3 pTmp0 = pii0 + (dir * t0);
const float3 pTmp1 = pii0 + (dir * t1);
// get the intersection points in volume-space
const float3 p0 = pTmp0 * v->GetHScales();
const float3 p1 = pTmp1 * v->GetHScales();
// get the distances from the start of the ray
// to the intersection points in volume-space
const float dSq0 = (p0 - pi0).SqLength();
const float dSq1 = (p1 - pi0).SqLength();
// if one of the intersection points is closer to p0
// than the end of the ray segment, the hit is valid
const int b0 = (t0 > 0.0f && dSq0 <= segLenSq) * CQ_POINT_ON_RAY;
const int b1 = (t1 > 0.0f && dSq1 <= segLenSq) * CQ_POINT_ON_RAY;
if (q != NULL) {
q->b0 = b0; q->b1 = b1;
q->t0 = t0; q->t1 = t1;
q->p0 = p0; q->p1 = p1;
}
return (b0 == CQ_POINT_ON_RAY || b1 == CQ_POINT_ON_RAY);
}
}
return false;
}
bool CCollisionHandler::IntersectCylinder(const CollisionVolume* v, const float3& pi0, const float3& pi1, CollisionQuery* q)
{
const int pAx = v->GetPrimaryAxis();
const int sAx0 = v->GetSecondaryAxis(0);
const int sAx1 = v->GetSecondaryAxis(1);
const float3& ahs = v->GetHScales();
const float3& ahsq = v->GetHSqScales();
const float ratio =
((pi0[sAx0] * pi0[sAx0]) / ahsq[sAx0]) +
((pi0[sAx1] * pi0[sAx1]) / ahsq[sAx1]);
if ((math::fabs(pi0[pAx]) < ahs[pAx]) && (ratio <= 1.0f)) {
if (q != NULL) {
// terminate early in the special case
// that ray-segment originated within v
q->b0 = CQ_POINT_IN_VOL; q->p0 = ZeroVector;
q->b1 = CQ_POINT_IN_VOL; q->p1 = ZeroVector;
}
return true;
}
// ray direction in volume-space
const float3 dir = (pi1 - pi0).SafeNormalize();
// ray direction in (unit) cylinder-space
float3 diir = ZeroVector;
// ray terminals in (unit) cylinder-space
float3 pii0 = pi0;
float3 pii1 = pi1;
// end-cap plane normals in volume-space
float3 n0 = ZeroVector;
float3 n1 = ZeroVector;
// (unit) cylinder-space to volume-space transformation
float3 inv(1.0f, 1.0f, 1.0f);
// unit-cylinder surface equation params
float a = 0.0f;
float b = 0.0f;
float c = 0.0f;
switch (pAx) {
case CollisionVolume::COLVOL_AXIS_X: {
pii0.y = pi0.y * v->GetHIScales().y;
pii0.z = pi0.z * v->GetHIScales().z;
pii1.y = pi1.y * v->GetHIScales().y;
pii1.z = pi1.z * v->GetHIScales().z;
inv.y = v->GetHScales().y;
inv.z = v->GetHScales().z;
diir = (pii1 - pii0).SafeNormalize();
n0.x = -1.0f; // left
n1.x = 1.0f; // right
// yz-surface equation params
a = (diir.y * diir.y) + (diir.z * diir.z);
b = ((pii0.y * diir.y) + (pii0.z * diir.z)) * 2.0f;
c = (pii0.y * pii0.y) + (pii0.z * pii0.z) - 1.0f;
} break;
case CollisionVolume::COLVOL_AXIS_Y: {
pii0.x = pi0.x * v->GetHIScales().x;
pii0.z = pi0.z * v->GetHIScales().z;
pii1.x = pi1.x * v->GetHIScales().x;
pii1.z = pi1.z * v->GetHIScales().z;
inv.x = v->GetHScales().x;
inv.z = v->GetHScales().z;
diir = (pii1 - pii0).SafeNormalize();
n0.y = 1.0f; // top
n1.y = -1.0f; // bottom
// xz-surface equation params
a = (diir.x * diir.x) + (diir.z * diir.z);
b = ((pii0.x * diir.x) + (pii0.z * diir.z)) * 2.0f;
c = (pii0.x * pii0.x) + (pii0.z * pii0.z) - 1.0f;
} break;
case CollisionVolume::COLVOL_AXIS_Z: {
pii0.x = pi0.x * v->GetHIScales().x;
pii0.y = pi0.y * v->GetHIScales().y;
pii1.x = pi1.x * v->GetHIScales().x;
pii1.y = pi1.y * v->GetHIScales().y;
inv.x = v->GetHScales().x;
inv.y = v->GetHScales().y;
diir = (pii1 - pii0).SafeNormalize();
n0.z = 1.0f; // front
n1.z = -1.0f; // back
// xy-surface equation params
a = (diir.x * diir.x) + (diir.y * diir.y);
b = ((pii0.x * diir.x) + (pii0.y * diir.y)) * 2.0f;
c = (pii0.x * pii0.x) + (pii0.y * pii0.y) - 1.0f;
} break;
}
// volume-space intersection points
float3 p0 = ZeroVector;
float3 p1 = ZeroVector;
int b0 = CQ_POINT_NO_INT;
int b1 = CQ_POINT_NO_INT;
float
d = (b * b) - (4.0f * a * c),
rd = 0.0f, // math::sqrt(d) or 1/dp
dp = 0.0f, // dot(n{0, 1}, dir)
ra = 0.0f; // ellipsoid ratio of p{0, 1}
float s0 = 0.0f, t0 = 0.0f;
float s1 = 0.0f, t1 = 0.0f;
// get the length of the ray segment in volume-space
const float segLenSq = (pi1 - pi0).SqLength();
if (d >= -COLLISION_VOLUME_EPS) {
if (a != 0.0f) {
// quadratic eq.; one or two surface intersections
if (d < COLLISION_VOLUME_EPS) {
t0 = -b / (2.0f * a);
p0 = (pii0 + (diir * t0)) * inv;
s0 = (p0 - pi0).SqLength();
b0 = (s0 < segLenSq && math::fabs(p0[pAx]) < ahs[pAx]) * CQ_POINT_ON_RAY;
} else {
rd = fastmath::apxsqrt(d);
t0 = (-b - rd) / (2.0f * a);
t1 = (-b + rd) / (2.0f * a);
p0 = (pii0 + (diir * t0)) * inv;
p1 = (pii0 + (diir * t1)) * inv;
s0 = (p0 - pi0).SqLength();
s1 = (p1 - pi0).SqLength();
b0 = (s0 < segLenSq && math::fabs(p0[pAx]) < ahs[pAx]) * CQ_POINT_ON_RAY;
b1 = (s1 < segLenSq && math::fabs(p1[pAx]) < ahs[pAx]) * CQ_POINT_ON_RAY;
}
} else {
if (b != 0.0f) {
// linear eq.; one surface intersection
t0 = -c / b;
p0 = (pii0 + (diir * t0)) * inv;
s0 = (p0 - pi0).SqLength();
b0 = (s0 < segLenSq && math::fabs(p0[pAx]) < ahs[pAx]) * CQ_POINT_ON_RAY;
}
}
}
if (b0 == CQ_POINT_NO_INT) {
// p0 does not lie on ray segment, or does not fall
// between cylinder end-caps: check if segment goes
// through front cap (plane)
// NOTE: normal n0 and dir should not be orthogonal
dp = n0.dot(dir);
rd = (dp != 0.0f)? 1.0f / dp: 0.01f;
t0 = -(n0.dot(pi0) - ahs[pAx]) * rd;
p0 = pi0 + (dir * t0);
s0 = (p0 - pi0).SqLength();
ra =
(((p0[sAx0] * p0[sAx0]) / ahsq[sAx0]) +
((p0[sAx1] * p0[sAx1]) / ahsq[sAx1]));
b0 = (t0 >= 0.0f && ra <= 1.0f && s0 <= segLenSq) * CQ_POINT_ON_RAY;
}
if (b1 == CQ_POINT_NO_INT) {
// p1 does not lie on ray segment, or does not fall
// between cylinder end-caps: check if segment goes
// through rear cap (plane)
// NOTE: normal n1 and dir should not be orthogonal
dp = n1.dot(dir);
rd = (dp != 0.0f)? 1.0f / dp: 0.01f;
t1 = -(n1.dot(pi0) - ahs[pAx]) * rd;
p1 = pi0 + (dir * t1);
s1 = (p1 - pi0).SqLength();
ra =
(((p1[sAx0] * p1[sAx0]) / ahsq[sAx0]) +
((p1[sAx1] * p1[sAx1]) / ahsq[sAx1]));
b1 = (t1 >= 0.0f && ra <= 1.0f && s1 <= segLenSq) * CQ_POINT_ON_RAY;
}
if (q != NULL) {
q->b0 = b0; q->b1 = b1;
q->t0 = t0; q->t1 = t1;
q->p0 = p0; q->p1 = p1;
}
return (b0 == CQ_POINT_ON_RAY || b1 == CQ_POINT_ON_RAY);
}
bool CCollisionHandler::IntersectBox(const CollisionVolume* v, const float3& pi0, const float3& pi1, CollisionQuery* q)
{
const bool ba = (math::fabs(pi0.x) < v->GetHScales().x);
const bool bb = (math::fabs(pi0.y) < v->GetHScales().y);
const bool bc = (math::fabs(pi0.z) < v->GetHScales().z);
if (ba && bb && bc) {
// terminate early in the special case
// that ray-segment originated within v
if (q != NULL) {
q->b0 = CQ_POINT_IN_VOL; q->p0 = ZeroVector;
q->b1 = CQ_POINT_IN_VOL; q->p1 = ZeroVector;
}
return true;
}
float tn = -9999999.9f;
float tf = 9999999.9f;
float t0 = 0.0f;
float t1 = 0.0f;
float t2 = 0.0f;
const float3 dir = (pi1 - pi0).SafeNormalize();
if (math::fabs(dir.x) < COLLISION_VOLUME_EPS) {
if (math::fabs(pi0.x) > v->GetHScales().x) {
return false;
}
} else {
if (dir.x > 0.0f) {
t0 = (-v->GetHScales().x - pi0.x) / dir.x;
t1 = ( v->GetHScales().x - pi0.x) / dir.x;
} else {
t1 = (-v->GetHScales().x - pi0.x) / dir.x;
t0 = ( v->GetHScales().x - pi0.x) / dir.x;
}
if (t0 > t1) { t2 = t1; t1 = t0; t0 = t2; }
if (t0 > tn) { tn = t0; }
if (t1 < tf) { tf = t1; }
if (tn > tf) { return false; }
if (tf < 0.0f) { return false; }
}
if (math::fabs(dir.y) < COLLISION_VOLUME_EPS) {
if (math::fabs(pi0.y) > v->GetHScales().y) {
return false;
}
} else {
if (dir.y > 0.0f) {
t0 = (-v->GetHScales().y - pi0.y) / dir.y;
t1 = ( v->GetHScales().y - pi0.y) / dir.y;
} else {
t1 = (-v->GetHScales().y - pi0.y) / dir.y;
t0 = ( v->GetHScales().y - pi0.y) / dir.y;
}
if (t0 > t1) { t2 = t1; t1 = t0; t0 = t2; }
if (t0 > tn) { tn = t0; }
if (t1 < tf) { tf = t1; }
if (tn > tf) { return false; }
if (tf < 0.0f) { return false; }
}
if (math::fabs(dir.z) < COLLISION_VOLUME_EPS) {
if (math::fabs(pi0.z) > v->GetHScales().z) {
return false;
}
} else {
if (dir.z > 0.0f) {
t0 = (-v->GetHScales().z - pi0.z) / dir.z;
t1 = ( v->GetHScales().z - pi0.z) / dir.z;
} else {
t1 = (-v->GetHScales().z - pi0.z) / dir.z;
t0 = ( v->GetHScales().z - pi0.z) / dir.z;
}
if (t0 > t1) { t2 = t1; t1 = t0; t0 = t2; }
if (t0 > tn) { tn = t0; }
if (t1 < tf) { tf = t1; }
if (tn > tf) { return false; }
if (tf < 0.0f) { return false; }
}
// get the intersection points in volume-space
const float3 p0 = pi0 + (dir * tn);
const float3 p1 = pi0 + (dir * tf);
// get the length of the ray segment in volume-space
const float segLenSq = (pi1 - pi0).SqLength();
// get the distances from the start of the ray
// to the intersection points in volume-space
const float dSq0 = (p0 - pi0).SqLength();
const float dSq1 = (p1 - pi0).SqLength();
// if one of the intersection points is closer to p0
// than the end of the ray segment, the hit is valid
const int b0 = (dSq0 <= segLenSq) * CQ_POINT_ON_RAY;
const int b1 = (dSq1 <= segLenSq) * CQ_POINT_ON_RAY;
if (q != NULL) {
q->b0 = b0; q->b1 = b1;
q->t0 = tn; q->t1 = tf;
q->p0 = p0; q->p1 = p1;
}
return (b0 == CQ_POINT_ON_RAY || b1 == CQ_POINT_ON_RAY);
}