mirror_php/moodle
1
0
Fork 0
mirror of https://github.com/moodle/moodle.git synced 2025-03-14 04:30:15 +01:00
Code Issues Projects Releases Wiki Activity

MDL-51914 qtype_ddmarker: fix checking points on the boundary

Browse Source 
All points on the boundary are now considered in the shape, on the
grounds that it is better to grade someone right for an edge case.
This commit is contained in:
Tim Hunt 2015-10-30 16:52:26 +00:00
parent 2d391d1b10
commit 0b4b0a7eea
3 changed files with 88 additions and 148 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

192
question/type/ddmarker/shapes.php
View File

@ -82,13 +82,13 @@ abstract class qtype_ddmarker_shape {
* @return bool
*/
protected function is_point_in_bounding_box($pointxy, $xleftytop, $xrightybottom) {
if ($pointxy[0] <= $xleftytop[0]) {
if ($pointxy[0] < $xleftytop[0]) {
return false;
} else if ($pointxy[0] >= $xrightybottom[0]) {
} else if ($pointxy[0] > $xrightybottom[0]) {
return false;
} else if ($pointxy[1] <= $xleftytop[1]) {
} else if ($pointxy[1] < $xleftytop[1]) {
return false;
} else if ($pointxy[1] >= $xrightybottom[1]) {
} else if ($pointxy[1] > $xrightybottom[1]) {
return false;
}
return true;
@ -300,7 +300,7 @@ class qtype_ddmarker_shape_circle extends qtype_ddmarker_shape {
public function is_point_in_shape($xy) {
$distancefromcentre = sqrt(pow(($xy[0] - $this->xcentre), 2) + pow(($xy[1] - $this->ycentre), 2));
return $distancefromcentre < $this->radius;
return $distancefromcentre <= $this->radius;
}
public function center_point() {
@ -380,84 +380,69 @@ class qtype_ddmarker_shape_polygon extends qtype_ddmarker_shape {
}
public function is_point_in_shape($xy) {
$pointatinfinity = new qtype_ddmarker_point(-1000000, $xy[1] + 1);
$pointtotest = new qtype_ddmarker_point($xy[0], $xy[1]);
$testsegment = new qtype_ddmarker_segment($pointatinfinity, $pointtotest);
// This code is based on the winding number algorithm from
// http://geomalgorithms.com/a03-_inclusion.html
// which comes with the following copyright notice:
// Copyright 2000 softSurfer, 2012 Dan Sunday
// This code may be freely used, distributed and modified for any purpose
// providing that this copyright notice is included with it.
// SoftSurfer makes no warranty for this code, and cannot be held
// liable for any real or imagined damage resulting from its use.
// Users of this code must verify correctness for their application.
$point = new qtype_ddmarker_point($xy[0], $xy[1]);
$windingnumber = 0;
foreach ($this->coords as $index => $coord) {
if ($index != 0) {
$a = new qtype_ddmarker_point($this->coords[$index - 1][0],
$this->coords[$index - 1][1]);
$start = new qtype_ddmarker_point($this->coords[$index][0], $this->coords[$index][1]);
if ($index < count($this->coords) - 1) {
$endindex = $index + 1;
} else {
$a = new qtype_ddmarker_point($this->coords[count($this->coords) - 1][0],
$this->coords[count($this->coords) - 1][1]);
$endindex = 0;
}
$b = new qtype_ddmarker_point($this->coords[$index][0],
$this->coords[$index][1]);
$segment = new qtype_ddmarker_segment($a, $b);
$intersects = $segment->intersects($testsegment);
if ($intersects === null) {
list($perturbedsegment, $testsegment) = $this->perturb($segment, $testsegment);
if ($index !== 0) {
$this->coords[$index - 1][0] = $perturbedsegment->a->x;
$this->coords[$index - 1][1] = $perturbedsegment->a->y;
} else {
$this->coords[count($this->coords) - 1][0] = $perturbedsegment->a->x;
$this->coords[count($this->coords) - 1][1] = $perturbedsegment->a->y;
$end = new qtype_ddmarker_point($this->coords[$endindex][0], $this->coords[$endindex][1]);
if ($start->y <= $point->y) {
if ($end->y >= $point->y) { // An upward crossing.
$isleft = $this->is_left($start, $end, $point);
if ($isleft == 0) {
return true; // The point is on the line.
} else if ($isleft > 0) {
// A valid up intersect.
$windingnumber += 1;
}
}
$this->coords[$index][0] = $perturbedsegment->b->x;
$this->coords[$index][1] = $perturbedsegment->b->y;
$intersects = $perturbedsegment->intersects($testsegment);
if ($intersects === null) {
throw new coding_exception('Polygon hit test code failed '.
'- Still touching end point after perturbation');
} else if ($intersects) {
$windingnumber++;
} else {
if ($end->y <= $point->y) { // A downward crossing.
$isleft = $this->is_left($start, $end, $point);
if ($isleft == 0) {
return true; // The point is on the line.
} else if ($this->is_left($start, $end, $point) < 0) {
// A valid down intersect.
$windingnumber -= 1;
}
}
} else if ($intersects) {
$windingnumber++;
}
}
return ($windingnumber % 2) ? true : false;
return $windingnumber != 0;
}
/**
* $v segment and this touch, move one of them slightly.
* @param qtype_ddmarker_segment $v
* @param int $ua
* @param int $ub
* Tests if a point is left / on / right of an infinite line.
*
* @param qtype_ddmarker_point $start first of two points on the infinite line.
* @param qtype_ddmarker_point $end second of two points on the infinite line.
* @param qtype_ddmarker_point $point the oint to test.
* @return number > 0 if the point is left of the line.
* = 0 if the point is on the line.
* < 0 if the point is right of the line.
*/
public function perturb($p, $q) {
list(, $ua, $ub) = $p->intersection_point($q);
$pt = 0.00001; // Perturbation factor.
$h = $p->a->dist($p->b);
if ($ua == 0) {
// ... q1, q2 intersects p1 exactly, move vertex p1 closer to p2.
$a = ($pt * $p->a->dist(new qtype_ddmarker_point($p->b->x, $p->a->y))) / $h;
$b = ($pt * $p->b->dist(new qtype_ddmarker_point($p->b->x, $p->a->y))) / $h;
$p->a->x = $p->a->x + $a;
$p->a->y = $p->a->y + $b;
} else if ($ua == 1) {
// ... q1, q2 intersects p2 exactly, move vertex p2 closer to p1.
$a = ($pt * $p->a->dist(new qtype_ddmarker_point($p->b->x, $p->a->y))) / $h;
$b = ($pt * $p->b->dist(new qtype_ddmarker_point($p->b->x, $p->a->y))) / $h;
$p->b->x = $p->b->x - $a;
$p->b->y = $p->b->y - $b;
} else if ($ub == 0) {
// ... p1, p2 intersects q1 exactly, move vertex q1 closer to q2.
$a = ($pt * $q->a->dist(new qtype_ddmarker_point($q->b->x, $q->a->y))) / $h;
$b = ($pt * $q->b->dist(new qtype_ddmarker_point($q->b->x, $q->a->y))) / $h;
$q->a->x = $q->a->x + $a;
$q->a->y = $q->a->y + $b;
} else if ($ub == 1) {
// ... p1, p2 intersects q2 exactly, move vertex q2 closer to q1.
$a = ($pt * $q->a->dist(new qtype_ddmarker_point($q->b->x, $q->a->y))) / $h;
$b = ($pt * $q->b->dist(new qtype_ddmarker_point($q->b->x, $q->a->y))) / $h;
$q->b->x = $q->b->x - $a;
$q->b->y = $q->b->y - $b;
}
return array($p, $q);
protected function is_left(qtype_ddmarker_point $start, qtype_ddmarker_point $end,
qtype_ddmarker_point $point) {
return ($end->x - $start->x) * ($point->y - $start->y)
- ($point->x - $start->x) * ($end->y - $start->y);
}
public function center_point() {
$center = array(round(($this->minxy[0] + $this->maxxy[0]) / 2),
round(($this->minxy[1] + $this->maxxy[1]) / 2));
@ -466,7 +451,6 @@ class qtype_ddmarker_shape_polygon extends qtype_ddmarker_shape {
} else {
return null;
}
}
}
@ -495,69 +479,3 @@ class qtype_ddmarker_point {
return sqrt(pow($this->x - $other->x, 2) + pow($this->y - $other->y, 2));
}
}
/**
* Defines a segment between two end points a and b.
*
* @copyright 2012 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class qtype_ddmarker_segment {
/** @var object First point */
public $a;
/** @var object Second point */
public $b;
public function __construct(qtype_ddmarker_point $a, qtype_ddmarker_point $b) {
$this->a = $a;
$this->b = $b;
}
/**
* Find if this segment intersects another segment $v.
* @param segment $v
* @return boolean does it intersect?
*/
public function intersects(qtype_ddmarker_segment $v) {
// Algorithm from: http://astronomy.swin.edu.au/~pbourke/geometry/lineline2d/
// $this is P1 to P2 and $v is P3 to P4.
list($d, $ua, $ub) = $this->intersection_point($v);
if ($d !== 0) { // The lines intersect at a point somewhere
// The values of $ua and $ub tell us where the intersection occurred.
if ( (($ua == 0 || $ua == 1 )&&($ub >= 0 && $ub <= 1))
|| (($ub == 0 || $ub == 1) && ($ua >= 0 && $ua <= 1))) {
// A value of exactly 0 or 1 means the intersection occurred right at the
// start or end of the line segment. For our purposes we will consider this
// NOT to be an intersection away from the intersecting line.
// Degenerate case - segment exactly touches a line.
return null;
} else if (($ua > 0 && $ua < 1) && ($ub > 0 && $ub < 1)) {
// A value between 0 and 1 means the intersection occurred within the
// line segment.
// Intersection occurs on both line segments.
return true;
} else {
// The lines do not intersect within the line segments.
return false;
}
} else { // The lines do not intersect.
return false;
}
}
public function intersection_point(qtype_ddmarker_segment $v) {
$d = (($v->b->y - $v->a->y) * ($this->b->x - $this->a->x)) -
(($v->b->x - $v->a->x) * ($this->b->y - $this->a->y));
if ($d != 0) { // The lines intersect at a point somewhere.
$ua = (($v->b->x - $v->a->x) * ($this->a->y - $v->a->y) -
($v->b->y - $v->a->y) * ($this->a->x - $v->a->x)) / $d;
$ub = (($this->b->x - $this->a->x) * ($this->a->y - $v->a->y) -
($this->b->y - $this->a->y) * ($this->a->x - $v->a->x)) / $d;
} else {
$ua = null;
$ub = null;
}
return array($d, $ua, $ub);
}
}

6
question/type/ddmarker/tests/question_test.php
View File

@ -130,11 +130,11 @@ class qtype_ddmarker_question_test extends basic_testcase {
// The second returned param in array is the max of correct choices or
// the actual number of items dragged.
$response1 = array('c1' => '50,50', 'c2' => '100,100', 'c3' => '100,100;200,200');
$response1 = array('c1' => '50,50', 'c2' => '110,110', 'c3' => '90,90;210,210');
$this->assertEquals(array(1, 4), $dd->get_num_parts_right($response1));
$response2 = array('c1' => '50,50;150,50;50,150',
'c2' => '100,100',
'c3' => '100,100;200,200');
'c2' => '110,110',
'c3' => '90,90;210,210');
$this->assertEquals(array(1, 6), $dd->get_num_parts_right($response2));
$response3 = array('c1' => '50,50;150,50;50,150',
'c2' => '',

38
question/type/ddmarker/tests/shapes_test.php
View File

@ -75,6 +75,16 @@ class qtype_ddmarker_shapes_test extends basic_testcase {
$this->assertTrue($shape->is_point_in_shape(array(11, 11)));
$this->assertTrue($shape->is_point_in_shape(array(19, 19)));
// Test points right on the edge are in.
$this->assertTrue($shape->is_point_in_shape(array(10, 10)));
$this->assertTrue($shape->is_point_in_shape(array(10, 20)));
$this->assertTrue($shape->is_point_in_shape(array(20, 20)));
$this->assertTrue($shape->is_point_in_shape(array(20, 10)));
$this->assertTrue($shape->is_point_in_shape(array(10, 15)));
$this->assertTrue($shape->is_point_in_shape(array(15, 10)));
$this->assertTrue($shape->is_point_in_shape(array(20, 15)));
$this->assertTrue($shape->is_point_in_shape(array(15, 20)));
// Should accept closed polygon coords or unclosed and it will model a closed polygon.
$shape = new qtype_ddmarker_shape_polygon('10, 10; 20, 10; 20, 20; 10, 20; 10, 10');
$this->assertTrue($shape->is_point_in_shape(array(15, 15)));
@ -114,8 +124,13 @@ class qtype_ddmarker_shapes_test extends basic_testcase {
public function test_circle_hit_test() {
$shape = new qtype_ddmarker_shape_circle('10, 10; 10');
$this->assertTrue($shape->is_point_in_shape(array(19, 10)));
$this->assertFalse($shape->is_point_in_shape(array(20, 10)));
$this->assertTrue($shape->is_point_in_shape(array(20, 10)));
$this->assertFalse($shape->is_point_in_shape(array(21, 10)));
$this->assertTrue($shape->is_point_in_shape(array(10, 1)));
$this->assertTrue($shape->is_point_in_shape(array(10, 0)));
$this->assertFalse($shape->is_point_in_shape(array(10, -1)));
$this->assertFalse($shape->is_point_in_shape(array(15, 25)));
$this->assertFalse($shape->is_point_in_shape(array(25, 15)));
$this->assertTrue($shape->is_point_in_shape(array(11, 11)));
@ -123,6 +138,9 @@ class qtype_ddmarker_shapes_test extends basic_testcase {
$this->assertTrue($shape->is_point_in_shape(array(17, 17)));
$this->assertTrue($shape->is_point_in_shape(array(3, 3)));
$this->assertFalse($shape->is_point_in_shape(array(2, 2)));
// Should be exactly on the boundary - 3, 4, 5 right-angled triangle.
$this->assertTrue($shape->is_point_in_shape(array(16, 18)));
}
public function test_rectangle_valdiation_test() {
@ -132,12 +150,16 @@ class qtype_ddmarker_shapes_test extends basic_testcase {
public function test_rectangle_hit_test() {
$shape = new qtype_ddmarker_shape_rectangle('1000, 4000; 500, 400');
$this->assertTrue($shape->is_point_in_shape(array(1001, 4001)));
$this->assertFalse($shape->is_point_in_shape(array(1000, 4000)));
$this->assertFalse($shape->is_point_in_shape(array(501, 3601)));
$this->assertTrue($shape->is_point_in_shape(array(1499, 4399)));
$this->assertFalse($shape->is_point_in_shape(array(25, 15)));
$this->assertTrue($shape->is_point_in_shape(array(1001, 4399)));
$this->assertTrue($shape->is_point_in_shape(array(1499, 4001)));
$this->assertFalse($shape->is_point_in_shape(array(999, 4200)));
$this->assertTrue($shape->is_point_in_shape(array(1000, 4200)));
$this->assertTrue($shape->is_point_in_shape(array(1001, 4200)));
$this->assertTrue($shape->is_point_in_shape(array(1499, 4200)));
$this->assertTrue($shape->is_point_in_shape(array(1500, 4200)));
$this->assertFalse($shape->is_point_in_shape(array(1501, 4200)));
$this->assertFalse($shape->is_point_in_shape(array(1250, 3999)));
$this->assertTrue($shape->is_point_in_shape(array(1250, 4000)));
$this->assertTrue($shape->is_point_in_shape(array(1250, 4400)));
$this->assertFalse($shape->is_point_in_shape(array(1250, 4401)));
}
}