star-cpr

commit 7cd0a118a05c25332792fcb754c006f5e7fafa86
parent 188a299ab4625cf5306af94f2c2d156623f0acd7
Author: Christophe Coustet <christophe.coustet@meso-star.com>
Date:   Tue, 21 Feb 2023 18:20:24 +0100

Allow callbacks to be NULL when checking for intersections

Diffstat:
M
src/scpr.h
 | 
10
+++++++---
M
src/scpr_intersector.c
 | 
21
+++++++++++++++------
M
src/test_scpr_intersector.c
 | 
31
++++++++++++++++++++-----------

3 files changed, 42 insertions(+), 20 deletions(-)
diff --git a/src/scpr.h b/src/scpr.h
@@ -84,13 +84,17 @@ struct scpr_callback_segment {
 };
 
 /* A struct holding callbacks that are called when carying an intersection check
- * on a bunch of segments. */
+ * on a bunch of segments.
+ * If a callbacks is NULL, the corresponding events are unreported, but at least
+ * 1 callback must be non NULL.
+ * If a callback call returns non-zero, the whole scpr_intersector_check call
+ * exits whith a RES_BAD_ARG error status without further processing. */
 struct scpr_intersector_check_callbacks {
-  void(*simple_intersection)
+  int(*simple_intersection)
     (struct scpr_callback_segment* segment1,
      struct scpr_callback_segment* segment2,
      void* ctx);
-  void(*colinear_segments)
+  int(*collinear_segments)
     (struct scpr_callback_segment* segment1,
      struct scpr_callback_segment* segment2,
      void* ctx);
diff --git a/src/scpr_intersector.c b/src/scpr_intersector.c
@@ -531,7 +531,7 @@ check_two_segments_intersection
     /* No intersection at all */
   }
   else if(ccw1 == 0 && ccw2 == 0 && ccw3 == 0 && ccw4 == 0) {
-    /* Colinear segments */
+    /* collinear segments */
     struct scpr_callback_segment arg1, arg2;
     arg1.polygon = polygon1;
     arg1.component = comp_idx1;
@@ -541,7 +541,12 @@ check_two_segments_intersection
     arg2.component = comp_idx2;
     arg2.first_vertex = r21;
     arg2.last_vertex = r22;
-    callbacks->colinear_segments(&arg1, &arg2, data);
+    if(callbacks->collinear_segments
+        && callbacks->collinear_segments(&arg1, &arg2, data))
+    {
+      res = RES_BAD_ARG;
+      goto error;
+    }
   }
   else if(ccw1 * ccw2 < 0 && ccw3 * ccw4 < 0) {
     /* Basic segment intersection */
@@ -554,8 +559,13 @@ check_two_segments_intersection
     arg2.component = comp_idx2;
     arg2.first_vertex = r21;
     arg2.last_vertex = r22;
-    callbacks->simple_intersection(&arg1, &arg2, data);
-  }
+    if(callbacks->simple_intersection
+        && callbacks->simple_intersection(&arg1, &arg2, data))
+    {
+      res = RES_BAD_ARG;
+      goto error;
+    }
+}
 
 exit:
   return res;
@@ -769,8 +779,7 @@ scpr_intersector_check
   res_T res = RES_OK;
 
   if(!intersector || !callbacks
-      || !callbacks->simple_intersection
-      || !callbacks->colinear_segments)
+      || (!callbacks->simple_intersection && !callbacks->collinear_segments))
   {
     res = RES_BAD_ARG;
     goto error;
diff --git a/src/test_scpr_intersector.c b/src/test_scpr_intersector.c
@@ -23,11 +23,11 @@
 #include <memory.h>
 
 struct cpt {
-  size_t basic, colinear;
+  size_t simple, collinear;
 };
 
-static void
-basic_intersection
+static int
+simple_intersection
   (struct scpr_callback_segment* segment1,
    struct scpr_callback_segment* segment2,
    void* data)
@@ -35,11 +35,12 @@ basic_intersection
   struct cpt* cpt = (struct cpt*)data;
   (void)segment1; (void)segment2;
   ASSERT(cpt);
-  cpt->basic++;
+  cpt->simple++;
+  return 0;
 }
 
-static void
-colinear_segments
+static int
+collinear_segments
   (struct scpr_callback_segment* segment1,
    struct scpr_callback_segment* segment2,
    void* data)
@@ -47,7 +48,8 @@ colinear_segments
   struct cpt* cpt = (struct cpt*)data;
   (void)segment1; (void)segment2;
   ASSERT(cpt);
-  cpt->colinear++;
+  cpt->collinear++;
+  return 0;
 }
 
 int
@@ -173,11 +175,18 @@ main(int argc, char** argv)
   BAD(scpr_intersector_check(NULL, &cb, NULL));
   BAD(scpr_intersector_check(inter, NULL, NULL));
   BAD(scpr_intersector_check(inter, &cb, NULL));
-  cb.simple_intersection = basic_intersection;
-  cb.colinear_segments = colinear_segments;
+  BAD(scpr_intersector_check(inter, &cb, &cpt)); /* Callbacks are all NULL */
+  /* Report only intersections */
+  cb.simple_intersection = simple_intersection;
+  OK(scpr_intersector_check(inter, &cb, &cpt));
+  CHK(cpt.simple == 2);
+  CHK(cpt.collinear == 0);
+  /* Report intersections and collinearity */
+  cb.collinear_segments = collinear_segments;
+  cpt.simple = cpt.collinear = 0;
   OK(scpr_intersector_check(inter, &cb, &cpt));
-  CHK(cpt.basic == 2);
-  CHK(cpt.colinear == 2);
+  CHK(cpt.simple == 2);
+  CHK(cpt.collinear == 2);
 
   OK(scpr_polygon_ref_put(p01));
   OK(scpr_polygon_ref_put(p23));