fix line tessellation

-js: 7cf7ef763d
2015-04-28 18:14:34 -07:00
parent 32e00b5a03
commit 3e928f41c8
1 changed files with 2 additions and 1 deletions
--- a/src/mbgl/renderer/line_bucket.cpp
+++ b/src/mbgl/renderer/line_bucket.cpp
@@ -183,8 +183,9 @@ void LineBucket::addGeometry(const std::vector<Coordinate>& vertices) {
                // Almost parallel lines
                joinNormal = nextNormal;
            } else {
+                const float direction = prevNormal.x * nextNormal.y - prevNormal.y * nextNormal.x > 0 ? -1 : 1;
                const float bevelLength = miterLength * util::mag(prevNormal + nextNormal) /
-                                          util::mag(prevNormal - nextNormal);
+                                          util::mag(prevNormal - nextNormal * direction);
                joinNormal = util::perp(joinNormal) * bevelLength;
            }