diff options
Diffstat (limited to 'extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp')
-rw-r--r-- | extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp b/extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp index f1682aaf65b..02a293e82ba 100644 --- a/extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp +++ b/extern/bullet2/src/BulletCollision/CollisionShapes/btConvexTriangleMeshShape.cpp @@ -204,3 +204,113 @@ const btVector3& btConvexTriangleMeshShape::getLocalScaling() const { return m_stridingMesh->getScaling(); } + +void btConvexTriangleMeshShape::calculatePrincipalAxisTransform(btTransform& principal, btVector3& inertia, btScalar& volume) const +{ + class CenterCallback: public btInternalTriangleIndexCallback + { + bool first; + btVector3 ref; + btVector3 sum; + btScalar volume; + + public: + + CenterCallback() : first(true), ref(0, 0, 0), sum(0, 0, 0), volume(0) + { + } + + virtual void internalProcessTriangleIndex(btVector3* triangle, int partId, int triangleIndex) + { + (void) triangleIndex; + (void) partId; + if (first) + { + ref = triangle[0]; + first = false; + } + else + { + btScalar vol = btFabs((triangle[0] - ref).triple(triangle[1] - ref, triangle[2] - ref)); + sum += (btScalar(0.25) * vol) * ((triangle[0] + triangle[1] + triangle[2] + ref)); + volume += vol; + } + } + + btVector3 getCenter() + { + return (volume > 0) ? sum / volume : ref; + } + + btScalar getVolume() + { + return volume * btScalar(1. / 6); + } + + }; + + class InertiaCallback: public btInternalTriangleIndexCallback + { + btMatrix3x3 sum; + btVector3 center; + + public: + + InertiaCallback(btVector3& center) : sum(0, 0, 0, 0, 0, 0, 0, 0, 0), center(center) + { + } + + virtual void internalProcessTriangleIndex(btVector3* triangle, int partId, int triangleIndex) + { + (void) triangleIndex; + (void) partId; + btMatrix3x3 i; + btVector3 a = triangle[0] - center; + btVector3 b = triangle[1] - center; + btVector3 c = triangle[2] - center; + btVector3 abc = a + b + c; + btScalar volNeg = -btFabs(a.triple(b, c)) * btScalar(1. / 6); + for (int j = 0; j < 3; j++) + { + for (int k = 0; k <= j; k++) + { + i[j][k] = i[k][j] = volNeg * (center[j] * center[k] + + btScalar(0.25) * (center[j] * abc[k] + center[k] * abc[j]) + + btScalar(0.1) * (a[j] * a[k] + b[j] * b[k] + c[j] * c[k]) + + btScalar(0.05) * (a[j] * b[k] + a[k] * b[j] + a[j] * c[k] + a[k] * c[j] + b[j] * c[k] + b[k] * c[j])); + } + } + btScalar i00 = -i[0][0]; + btScalar i11 = -i[1][1]; + btScalar i22 = -i[2][2]; + i[0][0] = i11 + i22; + i[1][1] = i22 + i00; + i[2][2] = i00 + i11; + sum[0] += i[0]; + sum[1] += i[1]; + sum[2] += i[2]; + } + + btMatrix3x3& getInertia() + { + return sum; + } + + }; + + CenterCallback centerCallback; + btVector3 aabbMax(btScalar(1e30),btScalar(1e30),btScalar(1e30)); + m_stridingMesh->InternalProcessAllTriangles(¢erCallback, -aabbMax, aabbMax); + btVector3 center = centerCallback.getCenter(); + principal.setOrigin(center); + volume = centerCallback.getVolume(); + + InertiaCallback inertiaCallback(center); + m_stridingMesh->InternalProcessAllTriangles(&inertiaCallback, -aabbMax, aabbMax); + + btMatrix3x3& i = inertiaCallback.getInertia(); + i.diagonalize(principal.getBasis(), btScalar(0.00001), 20); + inertia.setValue(i[0][0], i[1][1], i[2][2]); + inertia /= volume; +} + |