Function isLineSegmentInTriangle

src/aliceVision/mvsData/geometry.cpp:348–378

}

bool isLineSegmentInTriangle(Point3d& lpi, const Point3d& A, const Point3d& B, const Point3d& C, const Point3d& linePoint1, const Point3d& linePoint2)
{
    Point3d v0 = C - A;
    Point3d v1 = B - A;

    Point3d n = cross(v0.normalize(), v1.normalize()).normalize();

    Point3d lineVect = linePoint2 - linePoint1;

    // linePlaneIntersect(&P, linePoint, lineVect, A, &n);
    const double k = (dot(A, n) - dot(n, linePoint1)) / dot(n, lineVect);
    lpi = linePoint1 + lineVect * k;

    // Compute vectors
    const Point3d v2 = lpi - A;

    // Compute dot products
    const double dot00 = dot(v0, v0);
    const double dot01 = dot(v0, v1);
    const double dot02 = dot(v0, v2);
    const double dot11 = dot(v1, v1);
    const double dot12 = dot(v1, v2);

    // Compute barycentric coordinates
    const double invDenom = 1.0 / (dot00 * dot11 - dot01 * dot01);
    const double u = (dot11 * dot02 - dot01 * dot12) * invDenom;
    const double v = (dot00 * dot12 - dot01 * dot02) * invDenom;

    // Check if point is in triangle
    return (k >= 0.0) && (k <= 1.0) && (u > 0.0) && (v > 0.0) && (u + v < 1.0);
}

// P = A + u * (C - A) + v * (B - A)
Point2d computeBarycentricCoordinates(const Point2d& A, const Point2d& B, const Point2d& C, const Point2d& P)