From e04b19916ed2125097a96501f5f7bce9d2ed73a6 Mon Sep 17 00:00:00 2001
From: Erica Fischer <enf@felt.com>
Date: Fri, 8 Sep 2023 15:30:48 -0700
Subject: [PATCH] Self-intersections in the same feature don't count

---
 tile.cpp | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/tile.cpp b/tile.cpp
index 084c7232..d11a0e9a 100644
--- a/tile.cpp
+++ b/tile.cpp
@@ -1298,8 +1298,9 @@ struct joint {
 	draw p1;
 	draw mid;
 	draw p2;
+	size_t ring;
 
-	joint(draw one, draw hinge, draw two) {
+	joint(draw one, draw hinge, draw two, size_t r) {
 		if (one < two) {
 			p1 = one;
 			p2 = two;
@@ -1309,6 +1310,7 @@ struct joint {
 		}
 
 		mid = hinge;
+		ring = r;
 	}
 
 	bool operator<(const joint &o) const {
@@ -2284,10 +2286,20 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 
 									// j - 1 because we don't want the duplicate last point
 									for (size_t k = i; k < j - 1; k++) {
+										if (sf.geometry[k] == sf.geometry[(k + 1 - i) % (j - 1 - i) + i]) {
+											abort();
+										}
+
+										if (sf.geometry[(k + 1 - i) % (j - 1 - i) + i] ==
+										    sf.geometry[(k + 2 - i) % (j - 1 - i) + i]) {
+											abort();
+										}
+
 										shared_joints.emplace_back(
 											sf.geometry[k],
 											sf.geometry[(k + 1 - i) % (j - 1 - i) + i],
-											sf.geometry[(k + 2 - i) % (j - 1 - i) + i]);
+											sf.geometry[(k + 2 - i) % (j - 1 - i) + i],
+											seq);
 									}
 
 									printf("%lld,%lld ", sf.geometry[i].x, sf.geometry[i].y);
@@ -2441,9 +2453,13 @@ long long write_tile(decompressor *geoms, std::atomic<long long> *geompos_in, ch
 			for (size_t i = 0; i + 1 < shared_joints.size(); i++) {
 				if (shared_joints[i].mid == shared_joints[i + 1].mid) {
 					// printf("%lld,%lld: ", shared_joints[i].mid.x, shared_joints[i].mid.y);
-					if (shared_joints[i].p1 != shared_joints[i + 1].p1 ||
-					    shared_joints[i].p2 != shared_joints[i + 1].p2) {
+					if ((shared_joints[i].p1 != shared_joints[i + 1].p1 ||
+					     shared_joints[i].p2 != shared_joints[i + 1].p2) &&
+					    (shared_joints[i].ring != shared_joints[i + 1].ring)) {
 						shared_nodes.push_back(shared_joints[i].mid);
+						double lon, lat;
+						tile2lonlat(shared_joints[i].mid.x, shared_joints[i].mid.y, 32, &lon, &lat);
+						printf("{\"type\":\"Feature\",\"properties\":{},\"geometry\":{\"type\":\"Point\",\"coordinates\":[%f,%f]}}\n", lon, lat);
 						// printf("different\n");
 					} else {
 						// printf("same %lld,%lld to %lld,%lld\n", shared_joints[i].p1.x, shared_joints[i].p1.y, shared_joints[i].p2.x, shared_joints[i].p2.y);