From 677876e4294708784eceb47bfc73698673a6e910 Mon Sep 17 00:00:00 2001
From: Nicholas Bishop <nicholasbishop@gmail.com>
Date: Thu, 12 Jul 2012 05:55:07 +0000
Subject: Fix normals around root nodes of skin modifier output.

The direction for these are flipped from other end caps, so add a root
flag to indicate whether the cap polygon's vertex output order should be
reversed.

Fixes bug [#32079] Skin-modifier calculates root's normals wrong
projects.blender.org/tracker/index.php?func=detail&aid=32079&group_id=9&atid=498
---
 source/blender/modifiers/intern/MOD_skin.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/source/blender/modifiers/intern/MOD_skin.c b/source/blender/modifiers/intern/MOD_skin.c
index 46987f30205..f24898ccee2 100644
--- a/source/blender/modifiers/intern/MOD_skin.c
+++ b/source/blender/modifiers/intern/MOD_skin.c
@@ -91,6 +91,7 @@ typedef enum {
 	CAP_START = 1,
 	CAP_END = 2,
 	SEAM_FRAME = 4,
+	ROOT = 8
 } SkinNodeFlag;
 
 typedef struct Frame {
@@ -502,6 +503,9 @@ static void end_node_frames(int v, SkinNode *skin_nodes, const MVert *mvert,
 		/* End frame */
 		create_frame(&skin_nodes[v].frames[0], mvert[v].co, rad, mat, 0);
 	}
+
+	if (nodes[v].flag & MVERT_SKIN_ROOT)
+		skin_nodes[v].flag |= ROOT;
 }
 
 /* Returns 1 for seam, 0 otherwise */
@@ -1493,18 +1497,27 @@ static void skin_output_end_nodes(SkinOutput *so, SkinNode *skin_nodes,
 		}
 
 		if (sn->flag & CAP_START) {
-			add_poly(so,
-			         sn->frames[0].verts[3],
-			         sn->frames[0].verts[2],
-			         sn->frames[0].verts[1],
-			         sn->frames[0].verts[0]);
+			if (sn->flag & ROOT) {
+				add_poly(so,
+						 sn->frames[0].verts[0],
+						 sn->frames[0].verts[1],
+						 sn->frames[0].verts[2],
+						 sn->frames[0].verts[3]);
+			}
+			else {
+				add_poly(so,
+						 sn->frames[0].verts[3],
+						 sn->frames[0].verts[2],
+						 sn->frames[0].verts[1],
+						 sn->frames[0].verts[0]);
+			}
 		}
 		if (sn->flag & CAP_END) {
 			add_poly(so,
-			         sn->frames[1].verts[3],
-			         sn->frames[1].verts[2],
+			         sn->frames[1].verts[0],
 			         sn->frames[1].verts[1],
-			         sn->frames[1].verts[0]);
+			         sn->frames[1].verts[2],
+			         sn->frames[1].verts[3]);
 		}
 	}
 }
-- 
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