From d8233a3fe32bb3fd7d88b673b2c0d2f6dd10fd87 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 4 Sep 2007 14:16:17 +0000
Subject: [PATCH] Blender export: Create triangle strips (incomplete)

---
 mesh_export.py | 119 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 104 insertions(+), 15 deletions(-)

diff --git a/mesh_export.py b/mesh_export.py
index 93243336..016db5bf 100644
--- a/mesh_export.py
+++ b/mesh_export.py
@@ -55,13 +55,29 @@ class Face:
 		self.smooth_group=None
 		self.edges=[]
 		self.verts=[v for v in mf.verts]
+		self.flag=False
 	
 	def __getattr__(self, attr):
 		return getattr(self._mface, attr)
 
+	def get_following_vertex(self, *vt):
+		seen=False
+		indices=[v.index for v in vt]
+		for v in self.verts:
+			if v.index in indices:
+				seen=True
+			elif seen:
+				return v
+
+		if seen:
+			return self.verts[0]
+
+		return None
+
 
 class SmoothGroup:
-	def __init__(self):
+	def __init__(self, index):
+		self.index=index
 		self.faces=[]
 		self.verts=[]
 
@@ -94,14 +110,60 @@ class Exporter:
 		sg.faces.append(face)
 		queue=[face]
 		while queue:
-			f=queue.pop(0)
-			for e in f.edges:
+			cur=queue.pop(0)
+			for e in cur.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)
+					other=e.other_face(cur)
+					if other and not other.smooth_group:
+						other.smooth_group=sg
+						sg.faces.append(other)
+						queue.append(other)
+
+	def create_strip(self, face):
+		edge=None
+		for e in face.edges:
+			other=e.other_face(face)
+			if other and other.smooth_group.index==face.smooth_group.index and not other.flag:
+				edge=e
+				break
+
+		if not edge:
+			return None
+
+		v1=face.get_following_vertex(edge.v1, edge.v2)
+		v2=face.get_following_vertex(v1)
+		if len(face.verts)==4:
+			result=[v2, v1]
+		else:
+			result=[v1, v2]
+			
+		print edge.key
+		print [v.index for v in result]
+
+		while 1:
+			face.flag=True
+			print "face =",[v.index for v in face.verts]
+			print [e.key for e in face.edges]
+			for i in range(2, len(face.verts)):
+				v=face.get_following_vertex(result[-2], result[-1])
+				print v.index
+				result.append(v)
+			print [v.index for v in result]
+
+			i1=result[-2].index
+			i2=result[-1].index
+			ekey=(min(i1, i2), max(i1, i2))
+			for e in face.edges:
+				if e.key==ekey:
+					edge=e
+					break
+
+			next=edge.other_face(face)
+			if next.smooth_group.index!=face.smooth_group.index or next.flag:
+				break
+			face=next
+
+		return result
 
 	def export(self):
 		scene=Blender.Scene.GetCurrent()
@@ -127,10 +189,24 @@ class Exporter:
 		smooth_groups=[]
 		for f in faces:
 			if not f.smooth_group:
-				sg=SmoothGroup()
+				sg=SmoothGroup(len(smooth_groups))
 				smooth_groups.append(sg)
 				self.find_smooth_group(f, sg)
 
+		strips=[]
+		"""XXX Stripping and smoothing are currently imcompatible
+		for sg in smooth_groups:
+			for f in sg.faces:
+				if not f.flag:
+					strip=self.create_strip(f)
+					if strip:
+						strips.append(strip)"""
+
+		for i in mesh.verts:
+			print i.co
+
+		#print [v.index for v in strips[0]]
+
 		verts=[]
 		for sg in smooth_groups:
 			sg.find_vertices()
@@ -138,16 +214,29 @@ class Exporter:
 				v.index=len(verts)
 				verts.append(v)
 
+		#print [v.index for v in strips[0]]
+
 		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("\tnormal3 %f %f %f;\n"%tuple(v.no))
+			self.out_file.write("\tvertex3 %f %f %f;\n"%tuple(v.co))
 		self.out_file.write("};\n")
-		self.out_file.write("batch TRIANGLES\n{\n")
+		for s in strips:
+			self.out_file.write("batch TRIANGLE_STRIP\n{\n\tindices")
+			for v in s:
+				self.out_file.write(" %u"%v.index)
+			self.out_file.write(";\n};\n")
+
+		first=True
 		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")
+			if not f.flag:
+				if first:
+					self.out_file.write("batch TRIANGLES\n{\n")
+					first=False
+				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))
+		if not first:
+			self.out_file.write("};\n")
 
 
 class FrontEnd:
-- 
2.43.0