bool Utils::CalcTangent( const Vec2d& p1, const Vec2d& p2, const Vec2d& p3, Vec2d& tangent )
{
Vec2d mid1 = (p1 + p2) * 0.5;
Vec2d norm1 = VecNorm(p2 - p1);
Vec2d mid2 = (p2 + p3) * 0.5;
Vec2d norm2 = VecNorm(p3 - p2);
double t;
if( !LineCrossesLine(mid1, norm1, mid2, norm2, t) )
{
if( p1 != p3 )
{
tangent = VecUnit(p3 - p1);
return true;
}
return false;
}
Vec2d centre = mid1 + norm1 * t;
// tangent = p2 - centre;
// tangent = VecNorm(p2 - centre);
tangent = VecUnit(VecNorm(p2 - centre));
if( norm1 * (p3 - p1) < 0 )
tangent = -tangent;
return true;
}
//==========================================================================*
// Utility to find crossing point (Schnittpunkt zweier Geraden)
//--------------------------------------------------------------------------*
bool TUtils::LineCrossesLineXY(
const TVec3d& p0,
const TVec3d& v0,
const TVec3d& p1,
const TVec3d& v1,
double& t )
{
return LineCrossesLine(p0.x, p0.y, v0.x, v0.y, p1.x, p1.y, v1.x, v1.y, t);
}
double Utils::CalcCurvatureTan( const Vec2d& p1, const Vec2d& tangent, const Vec2d& p2 )
{
Vec2d v = VecUnit(VecNorm(tangent));
Vec2d u = VecNorm(p2 - p1);
Vec2d q = (p1 + p2) * 0.5;
double radius;
if( !LineCrossesLine(p1, v, q, u, radius) )
return 0;
else
return 1.0 / radius;
}
bool Utils::LineCrossesLine( const Vec2d& p0, const Vec2d& v0, const Vec2d& p1, const Vec2d& v1, double& t )
{
return LineCrossesLine(p0.x, p0.y, v0.x, v0.y, p1.x, p1.y, v1.x, v1.y, t);
}
