From 87ce3d5626a55cadda1df875a02a6b3420a52fba Mon Sep 17 00:00:00 2001
From: Joseph Eagar <joeedh@gmail.com>
Date: Sat, 23 May 2009 16:53:03 +0000
Subject: [PATCH] ngons are tesselated properly again, using scanfill, though
 need to get it to update on transform step still.  also made normals for
 ngons sortof work, but it's still buggy and not looking right :-/

---
 .../blenkernel/intern/editderivedbmesh.c      | 69 +++++++++++++++----
 source/blender/bmesh/intern/bmesh_polygon.c   | 10 +++
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/source/blender/blenkernel/intern/editderivedbmesh.c b/source/blender/blenkernel/intern/editderivedbmesh.c
index c51375b3417..55f43733ba6 100644
--- a/source/blender/blenkernel/intern/editderivedbmesh.c
+++ b/source/blender/blenkernel/intern/editderivedbmesh.c
@@ -58,6 +58,7 @@
 #include "BLI_edgehash.h"
 #include "BLI_linklist.h"
 #include "BLI_memarena.h"
+#include "BLI_scanfill.h"
 
 #include "BKE_cdderivedmesh.h"
 #include "BKE_customdata.h"
@@ -112,7 +113,9 @@ BMEditMesh *TM_Copy(BMEditMesh *tm)
 	tm2->bm = BM_Copy_Mesh(tm->bm);
 	TM_RecalcTesselation(tm2);
 
-	tm2->vert_index = tm2->edge_index = tm2->face_index = NULL;
+	tm2->vert_index = NULL;
+	tm2->edge_index = NULL;
+	tm2->face_index = NULL;
 
 	return tm2;
 }
@@ -134,21 +137,59 @@ void TM_RecalcTesselation(BMEditMesh *tm)
 		/*don't consider two-edged faces*/
 		if (f->len < 3) continue;
 		
-		/*for now, just do a triangle fan, in the future,
-		  use scanfill*/
-		l = BMIter_New(&liter, bm, BM_LOOPS_OF_FACE, f);
-		for (; l; l=BMIter_Step(&liter)) {
-			if (l == f->loopbase) continue;
-			if ((BMLoop*)l->head.next == f->loopbase) continue;
+		if (f->len <= 4) {
+			/*triangle fan for quads.  should be recoded to
+			  just add one tri for tris, and two for quads,
+			  but this code works for now too.*/
+			l = BMIter_New(&liter, bm, BM_LOOPS_OF_FACE, f);
+			for (; l; l=BMIter_Step(&liter)) {
+				if (l == f->loopbase) continue;
+				if ((BMLoop*)l->head.next == f->loopbase) continue;
 
-			V_GROW(looptris);
-			V_GROW(looptris);
-			V_GROW(looptris);
+				V_GROW(looptris);
+				V_GROW(looptris);
+				V_GROW(looptris);
 
-			looptris[i*3] = l;
-			looptris[i*3+1] = (BMLoop*)l->head.next;
-			looptris[i*3+2] = f->loopbase;
-			i += 1;
+				looptris[i*3] = l;
+				looptris[i*3+1] = (BMLoop*)l->head.next;
+				looptris[i*3+2] = f->loopbase;
+				i += 1;
+			}
+		} else {
+			/*scanfill time*/
+			EditVert *v, *lastv=NULL, *firstv=NULL;
+			EditEdge *e;
+			EditFace *efa;
+
+			l = BMIter_New(&liter, bm, BM_LOOPS_OF_FACE, f);
+			for (; l; l=BMIter_Step(&liter)) {
+				v = BLI_addfillvert(l->v->co);
+				v->tmp.p = l;
+				
+				if (lastv) {
+					e = BLI_addfilledge(lastv, v);
+				}
+
+				lastv = v;
+				if (firstv==NULL) firstv = v;
+			}
+
+			/*complete the loop*/
+			BLI_addfilledge(firstv, v);
+
+			BLI_edgefill(0, 0);
+			
+			for (efa = fillfacebase.first; efa; efa=efa->next) {
+				V_GROW(looptris);
+				V_GROW(looptris);
+				V_GROW(looptris);
+
+				looptris[i*3] = efa->v1->tmp.p;
+				looptris[i*3+1] = efa->v2->tmp.p;
+				looptris[i*3+2] = efa->v3->tmp.p;
+				i += 1;
+			}
+			BLI_end_edgefill();
 		}
 	}
 
diff --git a/source/blender/bmesh/intern/bmesh_polygon.c b/source/blender/bmesh/intern/bmesh_polygon.c
index 54144cbebcd..c013952a622 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.c
+++ b/source/blender/bmesh/intern/bmesh_polygon.c
@@ -117,6 +117,15 @@ static void compute_poly_normal(float normal[3], float (*verts)[3], int nverts)
 	}
 	
 	l = sqrt(n[0]*n[0]+n[1]*n[1]+n[2]*n[2]);
+
+	if (l == 0.0) {
+		normal[0] = 0.0f;
+		normal[1] = 0.0f;
+		normal[2] = 1.0f;
+
+		return;
+	}
+
 	n[0] /= l;
 	n[1] /= l;
 	n[2] /= l;
@@ -396,6 +405,7 @@ void bmesh_update_face_normal(BMesh *bm, BMFace *f, float (*projectverts)[3])
 		do{
 			VECCOPY(projectverts[i], l->v->co);
 			l = (BMLoop*)(l->head.next);
+			i += 1;
 		}while(l!=f->loopbase);
 
 		compute_poly_plane(projectverts, f->len);