Bug: Produces zero length edges

[enduguXL]

Hello
Thanks for the lib!

jcvBounds min x -6.418 y -5.500 max x 3.140 y 0.009
jcvPoints[0] x -5.544 y -3.492
jcvPoints[1] x -5.010 y -4.586
jcvPoints[2] x 3.030 y -3.045
jcvPoints[3] x -5.279 y -5.474
edge[0] pos[0] x -1.318 y -2.105 pos[1] x -1.428 y 0.009
edge[1] pos[0] x -0.667 y -5.500 pos[1] x -1.318 y -2.105
edge[2] pos[0] x -0.762 y -5.500 pos[1] x -0.762 y -5.500
edge[3] pos[0] x -6.418 y -4.618 pos[1] x -6.418 y -4.618
edge[4] pos[0] x -6.418 y -4.596 pos[1] x -1.318 y -2.105
edge[5] pos[0] x -6.418 y -4.643 pos[1] x -3.598 y -5.500

Gray lines are XY axis
Green box is bounds
Green lines are valid edges
Green crosses are input points
Two magenta crosses are problematic edge2 and edge3

I'm using double
#define JC_VORONOI_IMPLEMENTATION
#define JCV_REAL_TYPE double
#define JCV_ATAN2 atan2
#define JCV_SQRT sqrt
#define JCV_FABS fabs
#include <jc_voronoi/jc_voronoi.h>

[david94133]

I found this too. Edges with zero length are detected on line 1060:

if( jcv_point_eq(&e->pos[0], &e->pos[1]) ) ...

The spurious edge could be removed at that point, but edges are stored in a singly-linked list, so removing it is expensive. In my own project I just discard zero-length edges as I process them.

There are no back-links (for example from half edges to edges) to check for, so just discarding is sufficient.

[JCash]

As @david94133 mentions, the edges are inside a singly linked list.

I don't want to add extra memory or operations for a doubly linked list, due to the fact that iterating over the edges isn't the main part of this library, and also since skipping the invalid edges is easily done when required.

Therefore I added an iterator function const jcv_edge* jcv_diagram_get_next_edge( const jcv_edge* edge ); to do this automatically. I've updated the examples, and added a test for this too.

Will close this issue once it's merged into master.

[JCash]

Fixed in #26 (v0.5.0)