libix2: fix depth maintenance precedence

*depth-- should be (*depth)-- etc.

surprisingly this went unnoticed for some time but I haven't
really been using libix[23] in anything other than sars which
didn't get much play/testing etc.  But a quick ASAN run
immediately uncovered this one.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/ix2.c b/src/ix2.c
index e87cf2c..da02f07 100644
--- a/src/ix2.c
+++ b/src/ix2.c
@@ -368,7 +368,7 @@ static ix2_object_t * add_object(ix2_t *ix2, unsigned *depth, ix2_node_t *node,
 		bb2f_t	quadrants[4];
 		int	i;
 
-		*depth++;
+		(*depth)++;
 		init_quadrants(quadrants, node_aabb, &node->center);
 		for (i = 0; i < 4; i++) {
 			if (!aabb_overlap(NULL, NULL, &quadrants[i], &object->position, &object->origin, &object->aabb))
@@ -377,7 +377,7 @@ static ix2_object_t * add_object(ix2_t *ix2, unsigned *depth, ix2_node_t *node,
 			if (!add_object(ix2, depth, &node->children[i], &quadrants[i], object, reference_cache))
 				goto _fail;
 		}
-		*depth--;
+		(*depth)--;
 
 		return object;
 	}
@@ -388,10 +388,10 @@ static ix2_object_t * add_object(ix2_t *ix2, unsigned *depth, ix2_node_t *node,
 
 	/* If the node is overflowing, split it */
 	if (node->n_objects > ix2->max_per_node && *depth < ix2->max_depth) {
-		*depth++;
+		(*depth)++;
 		if (!split_node(ix2, depth, node, node_aabb))
 			goto _fail;
-		*depth--;
+		(*depth)--;
 	}
 
 	return object;