From 4260be2445fb9ee93a9fab312c1f5c8fc5e9e281 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Sun, 5 Feb 2017 09:39:05 +0000
Subject: [PATCH] DXF: mark POLYLINE as 3d if any of the points have non-zero
 Z.

This commit follows 41365c5, which enabled export of Z coordinate
by using POLYLINE instead of LWPOLYLINE. After this commit, only
the AcDb2dPolyline/AcDb2dVertex are used when exporting flat views,
which may improve compatibility with 2d design packages.
---
 extlib/libdxfrw      | 2 +-
 src/exportvector.cpp | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/extlib/libdxfrw b/extlib/libdxfrw
index 8f958955..3475a9bf 160000
--- a/extlib/libdxfrw
+++ b/extlib/libdxfrw
@@ -1 +1 @@
-Subproject commit 8f958955f54668c142ded760dc951ffd16d9c71b
+Subproject commit 3475a9bf811afddde7d0638fbcc2b0200d542b07
diff --git a/src/exportvector.cpp b/src/exportvector.cpp
index aa8fed13..5ab335d0 100644
--- a/src/exportvector.cpp
+++ b/src/exportvector.cpp
@@ -129,6 +129,10 @@ public:
             hStyle hs = { e->kind };
             polyline = {};
             assignEntityDefaults(&polyline, hs);
+
+            if(!(EXACT(start->pos.z == 0.0) && EXACT(next->pos.z == 0.0))) {
+                polyline.flags |= 8 /* 3d polyline */;
+            }
             polyline.vertlist.push_back(
                 new DRW_Vertex(start->pos.x, start->pos.y, start->pos.z, 0.0));
             polyline.vertlist.push_back(
@@ -136,6 +140,9 @@ public:
         };
 
         auto nextFunc = [&](PolylineBuilder::Vertex *next, PolylineBuilder::Edge *e) {
+            if(!EXACT(next->pos.z == 0.0)) {
+                polyline.flags |= 8 /* 3d polyline */;
+            }
             polyline.vertlist.push_back(
                 new DRW_Vertex(next->pos.x, next->pos.y, next->pos.z, 0.0));
         };