void MeshMassPropertiesTests::testClosedTetrahedronMesh() {
// given a tetrahedron as a closed mesh of four tiangles
// verify MeshMassProperties computes the right nubers
// these numbers from the Tonon paper:
VectorOfPoints points;
points.push_back(btVector3(8.33220f, -11.86875f, 0.93355f));
points.push_back(btVector3(0.75523f, 5.00000f, 16.37072f));
points.push_back(btVector3(52.61236f, 5.00000f, -5.38580f));
points.push_back(btVector3(2.00000f, 5.00000f, 3.00000f));
btScalar expectedVolume = 1873.233236f;
btMatrix3x3 expectedInertia;
expectedInertia[0][0] = 43520.33257f;
expectedInertia[1][1] = 194711.28938f;
expectedInertia[2][2] = 191168.76173f;
expectedInertia[1][2] = -4417.66150f;
expectedInertia[2][1] = -4417.66150f;
expectedInertia[0][2] = 46343.16662f;
expectedInertia[2][0] = 46343.16662f;
expectedInertia[0][1] = -11996.20119f;
expectedInertia[1][0] = -11996.20119f;
btVector3 expectedCenterOfMass = 0.25f * (points[0] + points[1] + points[2] + points[3]);
VectorOfIndices triangles;
pushTriangle(triangles, 0, 2, 1);
pushTriangle(triangles, 0, 3, 2);
pushTriangle(triangles, 0, 1, 3);
pushTriangle(triangles, 1, 2, 3);
// compute mass properties
MeshMassProperties mesh(points, triangles);
// verify
QCOMPARE_WITH_ABS_ERROR(mesh._volume, expectedVolume, acceptableRelativeError * expectedVolume);
QCOMPARE_WITH_ABS_ERROR(mesh._centerOfMass, expectedCenterOfMass, acceptableAbsoluteError);
QCOMPARE_WITH_RELATIVE_ERROR(mesh._inertia, expectedInertia, acceptableRelativeError);
// test again, but this time shift the points so that the origin is definitely OUTSIDE the mesh
btVector3 shift = points[0] + expectedCenterOfMass;
for (int i = 0; i < (int)points.size(); ++i) {
points[i] += shift;
}
expectedCenterOfMass = 0.25f * (points[0] + points[1] + points[2] + points[3]);
// compute mass properties
mesh.computeMassProperties(points, triangles);
// verify
// QCOMPARE_WITH_ABS_ERROR(mesh._volume, expectedVolume, acceptableRelativeError * expectedVolume);
// QCOMPARE_WITH_ABS_ERROR(mesh._centerOfMass, expectedCenterOfMass, acceptableAbsoluteError);
// QCOMPARE_WITH_RELATIVE_ERROR(mesh._inertia, expectedInertia, acceptableRelativeError);
}
Mesh Mesh::fromPointcloud(const VectorOfPoints &pointcloud, bool centralizeLoadedMesh, bool calculateTriangles)
{
Mesh m;
int n = pointcloud.size();
m.pointsMat = Matrix(n, 3);
for (int i = 0; i < n; i++)
{
const cv::Point3d &p = pointcloud.at(i);
m.pointsMat(i, 0) = p.x;
m.pointsMat(i, 1) = p.y;
m.pointsMat(i, 2) = p.z;
}
if (calculateTriangles) m.calculateTriangles();
m.recalculateMinMax();
if (centralizeLoadedMesh) m.centralize();
return m;
}
