From 3d6f8d2781beb692e11488c34871ec62174e58df Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 13 Aug 2022 22:44:58 +0300
Subject: [PATCH] Refactor creation of batches in the Blender exporter

---
 blender/io_mspgl/export_mesh.py | 20 +++------------
 blender/io_mspgl/mesh.py        | 43 ++++++++++++++++++++++++++++-----
 2 files changed, 41 insertions(+), 22 deletions(-)

diff --git a/blender/io_mspgl/export_mesh.py b/blender/io_mspgl/export_mesh.py
index 01238618..3f5acf9e 100644
--- a/blender/io_mspgl/export_mesh.py
+++ b/blender/io_mspgl/export_mesh.py
@@ -90,22 +90,10 @@ class MeshExporter:
 
 		statements.append(st)
 
-		if mesh.use_strips:
-			for s in mesh.vertex_sequence:
-				st = Statement("batch", Token("TRIANGLE_STRIP"))
-				for i in range(0, len(s), 32):
-					st.sub.append(Statement("indices", *(v.index for v in s[i:i+32])))
-				statements.append(st)
-		else:
-			st = Statement("batch", Token('TRIANGLES'))
-			for f in mesh.faces:
-				st.sub.append(Statement("indices", *(v.index for v in f.vertices)))
-			statements.append(st)
-
-		if mesh.lines:
-			st = Statement("batch", Token('LINES'))
-			for l in mesh.lines:
-				st.sub.append(Statement("indices", *(v.index for v in l.vertices)))
+		for b in mesh.batches:
+			st = Statement("batch", Token(b.primitive_type))
+			for i in range(0, len(b.vertices), 32):
+				st.sub.append(Statement("indices", *(v.index for v in b.vertices[i:i+32])))
 			statements.append(st)
 
 		task.set_progress(1.0)
diff --git a/blender/io_mspgl/mesh.py b/blender/io_mspgl/mesh.py
index bf5d108b..ba9db802 100644
--- a/blender/io_mspgl/mesh.py
+++ b/blender/io_mspgl/mesh.py
@@ -75,6 +75,12 @@ class VertexGroup:
 			self.weight = 0.0
 
 
+class Batch:
+	def __init__(self, pt):
+		self.primitive_type = pt
+		self.vertices = []
+
+
 class Face:
 	def __init__(self, face):
 		self.index = face.index
@@ -158,6 +164,7 @@ class Mesh:
 		self.use_uv = mesh.use_uv
 		self.tangent_uvtex = mesh.tangent_uvtex
 		self.use_strips = mesh.use_strips
+		self.use_lines = mesh.use_lines
 		self.vertex_groups = mesh.vertex_groups
 
 		# Clone basic data
@@ -242,7 +249,7 @@ class Mesh:
 					if normal_prop and normal_prop.texture:
 						self.tangent_vecs = True
 
-		self.vertex_sequence = []
+		self.batches = []
 
 	def transform(self, matrix):
 		for v in self.vertices:
@@ -634,6 +641,17 @@ class Mesh:
 		self.reorder_faces(subtask)
 
 		subtask = task.task("Building sequence", 1.0)
+		if self.use_strips:
+			self.build_tristrip_sequence(subtask)
+		else:
+			self.build_triangle_sequence(subtask)
+
+		if self.use_lines:
+			self.build_line_sequence()
+
+		self.reorder_vertices()
+
+	def build_tristrip_sequence(self, task):
 		sequence = None
 		for i, f in enumerate(self.faces):
 			if sequence:
@@ -657,10 +675,23 @@ class Mesh:
 					sequence += to_add
 
 			if not sequence:
-				sequence = f.vertices[:]
-				self.vertex_sequence.append(sequence)
+				self.batches.append(Batch("TRIANGLE_STRIP"))
+				sequence = self.batches[-1].vertices
+				sequence += f.vertices
+
+			task.set_progress(i/len(self.faces))
+
+	def build_triangle_sequence(self, task):
+		batch = Batch("TRIANGLES")
+		for f in self.faces:
+			batch.vertices += f.vertices
+		self.batches.append(batch)
 
-			subtask.set_progress(i/len(self.faces))
+	def build_line_sequence(self):
+		batch = Batch("LINES")
+		for l in self.lines:
+			batch.vertices += l.vertices
+		self.batches.append(batch)
 
 		self.reorder_vertices()
 
@@ -752,8 +783,8 @@ class Mesh:
 			v.index = -1
 
 		reordered_vertices = []
-		for s in self.vertex_sequence:
-			for v in s:
+		for b in self.batches:
+			for v in b.vertices:
 				if v.index<0:
 					v.index = len(reordered_vertices)
 					reordered_vertices.append(v)
-- 
2.45.2