From: Barak Itkin <lightningismyname@gmail.com>
Date: Sat, 16 Jun 2012 15:24:08 +0000 (+0300)
Subject: 1. Points were accidentally given in CW order (instead of CCW) order to the in_circle... 
X-Git-Tag: p2tc-0.1.0~35
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d738df3f7ea6960d21f3abb71c9e68774d6ddf6d;p=poly2tri-c

1. Points were accidentally given in CW order (instead of CCW) order to the in_circle function. This caused lots of trouble!
2. Fix the implementation of Lawson's legalization
---

diff --git a/poly2tri-c/refine/cdt.c b/poly2tri-c/refine/cdt.c
index ebe3093..b53c3b1 100644
--- a/poly2tri-c/refine/cdt.c
+++ b/poly2tri-c/refine/cdt.c
@@ -555,8 +555,7 @@ p2tr_cdt_try_flip (P2trCDT   *self,
 
   /* Check if the quadriliteral ADBC is concave (because if it is, we
    * can't flip the edge) */
-  if (p2tr_edge_angle_between_positive (DB, BC) >= G_PI - CDT_180_EPS ||
-      p2tr_edge_angle_between_positive (CA, AD) >= G_PI - CDT_180_EPS)
+  if (p2tr_triangle_circumcircle_contains_point (AB->tri, &D->c) != P2TR_INCIRCLE_IN)
     return NULL;
 
   p2tr_edge_remove (AB);
@@ -604,18 +603,15 @@ p2tr_cdt_flip_fix (P2trCDT     *self,
           P2trPoint *A  = P2TR_EDGE_START(edge), *B = edge->end;
           P2trPoint *C1 = p2tr_triangle_get_opposite_point (edge->tri, edge, FALSE);
           P2trPoint *C2 = p2tr_triangle_get_opposite_point (edge->mirror->tri, edge->mirror, FALSE);
-          if (p2tr_triangle_circumcircle_contains_point (edge->tri, &C2->c) == P2TR_INCIRCLE_IN
-              || p2tr_triangle_circumcircle_contains_point (edge->mirror->tri, &C1->c) == P2TR_INCIRCLE_IN)
+
+          P2trEdge *flipped = p2tr_cdt_try_flip (self, edge);
+          if (flipped != NULL)
             {
-              P2trEdge *flipped = p2tr_cdt_try_flip (self, edge);
-              if (flipped != NULL)
-                {
-                  p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (A, C1, TRUE));
-                  p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (A, C2, TRUE));
-                  p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (B, C1, TRUE));
-                  p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (B, C2, TRUE));
-                  p2tr_edge_unref (flipped);
-                }
+              p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (A, C1, TRUE));
+              p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (A, C2, TRUE));
+              p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (B, C1, TRUE));
+              p2tr_cdt_add_edge (candidates, p2tr_point_get_edge_to (B, C2, TRUE));
+              p2tr_edge_unref (flipped);
             }
         }
 
diff --git a/poly2tri-c/refine/delaunay-terminator.c b/poly2tri-c/refine/delaunay-terminator.c
index 000e1d9..2b87cb0 100644
--- a/poly2tri-c/refine/delaunay-terminator.c
+++ b/poly2tri-c/refine/delaunay-terminator.c
@@ -294,7 +294,10 @@ p2tr_dt_refine (P2trDelaunayTerminator *self,
           /* If no edge is encroached, then this must be
            * inside the triangulation domain!!! */
           if (triContaining_c == NULL)
-            p2tr_exception_geometric ("Should not happen! (%f, %f) is outside the domain!", c->x, c->y);
+            p2tr_exception_geometric ("Should not happen! (%f, %f) (Center of (%f,%f)->(%f,%f)->(%f,%f)) is outside the domain!", c->x, c->y,
+            t->edges[2]->end->c.x, t->edges[2]->end->c.y,
+            t->edges[0]->end->c.x, t->edges[0]->end->c.y,
+            t->edges[1]->end->c.x, t->edges[1]->end->c.y);
 
           /* Now, check if this point would encroach any edge
            * of the triangulation */
diff --git a/poly2tri-c/refine/rmath.c b/poly2tri-c/refine/rmath.c
index e0491c2..f644eaf 100644
--- a/poly2tri-c/refine/rmath.c
+++ b/poly2tri-c/refine/rmath.c
@@ -226,6 +226,7 @@ P2trOrientation p2tr_math_orient2d (const P2trVector2 *A,
 
 #define INCIRCLE_EPSILON 1e-9
 
+/* Points must be given in CCW order!!!!! */
 P2trInCircle
 p2tr_math_incircle (const P2trVector2 *A,
                     const P2trVector2 *B,
diff --git a/poly2tri-c/refine/triangle.c b/poly2tri-c/refine/triangle.c
index 5e9d522..2bf9a7f 100644
--- a/poly2tri-c/refine/triangle.c
+++ b/poly2tri-c/refine/triangle.c
@@ -278,10 +278,11 @@ P2trInCircle
 p2tr_triangle_circumcircle_contains_point (P2trTriangle      *self,
                                            const P2trVector2  *pt)
 {
+  /* Points must be given in CCW order! */
   return p2tr_math_incircle (
-      &P2TR_TRIANGLE_GET_POINT(self,0)->c,
-      &P2TR_TRIANGLE_GET_POINT(self,1)->c,
       &P2TR_TRIANGLE_GET_POINT(self,2)->c,
+      &P2TR_TRIANGLE_GET_POINT(self,1)->c,
+      &P2TR_TRIANGLE_GET_POINT(self,0)->c,
       pt);
 }