From b31a5873556fe046488587568fe35236227e3606 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 4 Sep 2007 09:06:55 +0000
Subject: [PATCH] Blender export: Add support for smoothing

---
 mesh_export.py | 121 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 117 insertions(+), 4 deletions(-)

diff --git a/mesh_export.py b/mesh_export.py
index 0e63d336..93243336 100644
--- a/mesh_export.py
+++ b/mesh_export.py
@@ -8,8 +8,79 @@ Group: 'Export'
 """
 
 import sys
+import math
 import Blender
 
+class Edge:
+	def __init__(self, me):
+		self._medge=me
+		self.faces=[]
+		self.smooth=False
+
+	def __getattr__(self, attr):
+		return getattr(self._medge, attr)
+
+	def check_smooth(self, limit):
+		if len(self.faces)!=2:
+			return
+
+		d=Blender.Mathutils.DotVecs(self.faces[0].no, self.faces[1].no)
+		if (d>limit and self.faces[0].smooth and self.faces[1].smooth) or d>0.999:
+			self.smooth=1
+
+	def other_face(self, f):
+		if f.index==self.faces[0].index:
+			if len(self.faces)>=2:
+				return self.faces[1]
+			else:
+				return None
+		else:
+			return self.faces[0]
+
+
+class Vertex:
+	def __init__(self, mv):
+		if mv.__class__==Vertex:
+			self._mvert=mv._mvert
+		else:
+			self._mvert=mv
+
+	def __getattr__(self, attr):
+		return getattr(self._mvert, attr)
+
+
+class Face:
+	def __init__(self, mf):
+		self._mface=mf
+		self.smooth_group=None
+		self.edges=[]
+		self.verts=[v for v in mf.verts]
+	
+	def __getattr__(self, attr):
+		return getattr(self._mface, attr)
+
+
+class SmoothGroup:
+	def __init__(self):
+		self.faces=[]
+		self.verts=[]
+
+	def find_vertices(self):
+		vert_map={}
+		for f in self.faces:
+			for i in range(len(f.verts)):
+				v=f.verts[i]
+				if v.index not in vert_map:
+					vt=Vertex(v)
+					if not f.smooth:
+						vt.no=f.no
+					self.verts.append(vt)
+					vert_map[v.index]=vt
+					f.verts[i]=vt
+				else:
+					f.verts[i]=vert_map[v.index]
+
+
 class Exporter:
 	def __init__(self, fn):
 		self.filename=fn
@@ -18,6 +89,20 @@ class Exporter:
 		else:
 			self.out_file=file(fn, "w")
 
+	def find_smooth_group(self, face, sg):
+		face.smooth_group=sg
+		sg.faces.append(face)
+		queue=[face]
+		while queue:
+			f=queue.pop(0)
+			for e in f.edges:
+				if e.smooth:
+					f2=e.other_face(f)
+					if f2 and not f2.smooth_group:
+						f2.smooth_group=sg
+						sg.faces.append(f2)
+						queue.append(f2)
+
 	def export(self):
 		scene=Blender.Scene.GetCurrent()
 
@@ -27,26 +112,54 @@ class Exporter:
 
 		mesh=obj.getData(mesh=True)
 
-		self.out_file.write("vertices NORMAL3,VERTEX3\n{\n")
-		for v in mesh.verts:
+		faces=[Face(f) for f in mesh.faces]
+
+		edges=dict([(e.key, Edge(e)) for e in mesh.edges])
+		for f in faces:
+			for e in f.edge_keys:
+				edges[e].faces.append(f)
+				f.edges.append(edges[e])
+
+		smooth_limit=math.cos(mesh.degr*math.pi/180)
+		for e in edges.itervalues():
+			e.check_smooth(smooth_limit)
+
+		smooth_groups=[]
+		for f in faces:
+			if not f.smooth_group:
+				sg=SmoothGroup()
+				smooth_groups.append(sg)
+				self.find_smooth_group(f, sg)
+
+		verts=[]
+		for sg in smooth_groups:
+			sg.find_vertices()
+			for v in sg.verts:
+				v.index=len(verts)
+				verts.append(v)
+
+		self.out_file.write("vertices NORMAL3_VERTEX3\n{\n")
+		for v in verts:
 			self.out_file.write("\tnormal3 %g %g %g;\n"%tuple(v.no))
 			self.out_file.write("\tvertex3 %g %g %g;\n"%tuple(v.co))
 		self.out_file.write("};\n")
 		self.out_file.write("batch TRIANGLES\n{\n")
-		for f in mesh.faces:
+		for f in faces:
 			for i in range(2, len(f.verts)):
 				self.out_file.write("\tindices %u %u %u;\n"%(f.verts[0].index, f.verts[i-1].index, f.verts[i].index))
 		self.out_file.write("};\n")
 
+
 class FrontEnd:
 	def run(self):
 		#self.export(None)
 		Blender.Window.FileSelector(self.export, "Export MSP GL mesh", Blender.sys.makename(ext='.mesh'))
-	
+
 	def export(self, fn):
 		exp=Exporter(fn)
 		exp.export()
 
+
 if __name__=="__main__":
 	fe=FrontEnd()
 	fe.run()
-- 
2.43.0