bool Plane::intersectLine(const Line3& line, Vector3* result) const
{
const Vector3 direction = line.delta();
float denominator = normal().dot( direction );
if ( denominator == 0 ) {
// line is coplanar, return origin
if ( distanceToPoint( line.start() ) == 0 ) {
if (result) {
result->copy( line.start() );
}
return true;
}
// Unsure if this is the correct method to handle this case.
return false;
}
float t = - ( line.start().dot( normal() ) + constant() ) / denominator;
if( (t < 0 || t > 1) ) {
return false;
}
if (result)
result->copy( direction ).multiplyScalar( t ).add( line.start() );
return true;
}
bool Plane::isIntersectionLine( const Line3& line ) const
{
// Note: this tests if a line intersects the plane, not whether it (or its end-points) are coplanar with it.
float startSign = distanceToPoint( line.start() );
float endSign = distanceToPoint( line.end() );
return ( startSign < 0 && endSign > 0 ) || ( endSign < 0 && startSign > 0 );
}