public function distance(Image_3D_Line $line)
{
// Calculate parameters for plane
$normale = $this->getNormale();
$A = $normale->getX();
$B = $normale->getY();
$C = $normale->getZ();
$D = -($normale->getX() * $this->_points[0]->getX() + $normale->getY() * $this->_points[0]->getY() + $normale->getZ() * $this->_points[0]->getZ());
// Calculate wheather and where line cuts the polygons plane
$lineDirection = $line->getDirection();
$denominator = -($A * $line->getX() + $B * $line->getY() + $C * $line->getZ() + $D);
$numerator = $A * $lineDirection->getX() + $B * $lineDirection->getY() + $C * $lineDirection->getZ();
// Nu cut, when denomintor equals 0 (parallel plane)
if ((int) ($denominator * 100000) === 0) {
return false;
}
if ((int) ($numerator * 100000) === 0) {
return false;
}
$t = $denominator / $numerator;
// No cut, when $t < 0 (plane is behind the camera)
if ($t <= 0) {
return false;
}
// TODO: Perhaps add max distance check with unified normale vector
// Calculate cutting point between line an plane
$cuttingPoint = $line->calcPoint($t);
// Perform fast check for point in bounding cube;
if ($cuttingPoint->getX() < $this->_boundingRect[0] || $cuttingPoint->getY() < $this->_boundingRect[1] || $cuttingPoint->getZ() < $this->_boundingRect[2] || $cuttingPoint->getX() > $this->_boundingRect[3] || $cuttingPoint->getY() > $this->_boundingRect[4] || $cuttingPoint->getZ() > $this->_boundingRect[5]) {
return false;
}
// perform exact check for point in polygon
$lastScalar = 0;
foreach ($this->_points as $nr => $point) {
$nextPoint = $this->_points[($nr + 1) % count($this->_points)];
$edge = new Image_3D_Vector($nextPoint->getX() - $point->getX(), $nextPoint->getY() - $point->getY(), $nextPoint->getZ() - $point->getZ());
$v = new Image_3D_Vector($cuttingPoint->getX() - $point->getX(), $cuttingPoint->getY() - $point->getY(), $cuttingPoint->getZ() - $point->getZ());
$scalar = $edge->crossProduct($v)->scalar($normale);
if ($scalar * $lastScalar >= 0) {
$lastScalar = $scalar;
} else {
return false;
}
}
// Point is in polygon, return distance to polygon
return $t;
}
