From 77b358049bc1ef38ea013175a485cecd71a173c9 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 20 Oct 2021 14:59:42 +0300
Subject: [PATCH] Refactor some parts of the Blender exporter to improve
 reusability

---
 blender/io_mspgl/export_object.py | 16 ++-----------
 blender/io_mspgl/export_scene.py  | 39 ++++++++++++++++++++-----------
 blender/io_mspgl/util.py          | 13 +++++++++++
 3 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/blender/io_mspgl/export_object.py b/blender/io_mspgl/export_object.py
index a8f55e92..b39307c8 100644
--- a/blender/io_mspgl/export_object.py
+++ b/blender/io_mspgl/export_object.py
@@ -2,19 +2,6 @@ import os
 import mathutils
 
 class ObjectExporter:
-	def compute_bounding_sphere(self, obj):
-		p1 = max(((v.co, v.co.length) for v in obj.data.vertices), key=lambda x:x[1])[0]
-		p2 = max(((v.co, (v.co-p1).length) for v in obj.data.vertices), key=lambda x:x[1])[0]
-		center = (p1+p2)/2
-		radius = (p1-p2).length/2
-		for v in obj.data.vertices:
-			d = v.co-center
-			if d.length>radius:
-				center += d*(1-radius/d.length)/2
-				radius = (radius+d.length)/2
-
-		return center, radius
-
 	def collect_object_lods(self, obj):
 		lods = [obj]
 		lods += sorted([c for c in obj.children if c.lod_for_parent], key=(lambda l: l.lod_index))
@@ -90,7 +77,8 @@ class ObjectExporter:
 		obj_res = Resource(obj.name+".object", "object")
 		statements = obj_res.statements
 
-		center, radius = self.compute_bounding_sphere(obj)
+		from .util import compute_bounding_sphere
+		center, radius = compute_bounding_sphere([v.co for v in obj.data.vertices])
 		statements.append(Statement("bounding_sphere_hint", *center, radius))
 
 		prev_mesh = None
diff --git a/blender/io_mspgl/export_scene.py b/blender/io_mspgl/export_scene.py
index 8666e98b..00f91c1a 100644
--- a/blender/io_mspgl/export_scene.py
+++ b/blender/io_mspgl/export_scene.py
@@ -122,10 +122,7 @@ class SceneExporter:
 		if scene.use_hdr:
 			seq_res.statements.append(Statement("hdr", True))
 
-		ss = Statement("clear")
-		ss.sub.append(Statement("color", 0.0, 0.0, 0.0, 0.0))
-		ss.sub.append(Statement("depth", 1.0))
-		seq_res.statements.append(ss)
+		self.add_clear(seq_res.statements, (0.0, 0.0, 0.0, 0.0), 1.0)
 
 		scene_res = resources[scene.name+".scene"]
 		seq_res.statements.append(seq_res.create_reference_statement("renderable", "content", scene_res))
@@ -142,17 +139,13 @@ class SceneExporter:
 				any_blended = True
 			s = s.background_set
 
-		if any_opaque:
-			ss = Statement("step", "", "content")
-			ss.sub.append(Statement("depth_test", Token("LEQUAL")))
-			ss.sub.append(seq_res.create_reference_statement("lighting", lighting_res))
-			seq_res.statements.append(ss)
 
+		main_tags = []
+		if any_opaque:
+			main_tags.append("")
 		if any_blended:
-			ss = Statement("step", "blended", "content")
-			ss.sub.append(Statement("depth_test", Token("LEQUAL")))
-			ss.sub.append(seq_res.create_reference_statement("lighting", lighting_res))
-			seq_res.statements.append(ss)
+
+		self.add_content_steps(seq_res, "content", lighting_res, main_tags)
 
 		if scene.use_ao:
 			ss = Statement("postprocessor")
@@ -180,3 +173,23 @@ class SceneExporter:
 			seq_res.statements.append(ss)
 
 		return seq_res
+
+	def add_clear(self, statements, color, depth):
+		from .datafile import Statement
+
+		st = Statement("clear")
+		if color is not None:
+			st.sub.append(Statement("color", *color))
+		if depth is not None:
+			st.sub.append(Statement("depth", depth))
+		statements.append(st)
+
+	def add_content_steps(self, seq_res, renderable, lighting, tags):
+		from .datafile import Statement, Token
+
+		for t in tags:
+			st = Statement("step", t, renderable)
+			st.sub.append(Statement("depth_test", Token("LEQUAL")))
+			if lighting:
+				st.sub.append(seq_res.create_reference_statement("lighting", lighting))
+			seq_res.statements.append(st)
diff --git a/blender/io_mspgl/util.py b/blender/io_mspgl/util.py
index e77e5447..4141e9f7 100644
--- a/blender/io_mspgl/util.py
+++ b/blender/io_mspgl/util.py
@@ -85,3 +85,16 @@ def get_linked_node_and_socket(node_tree, socket):
 		elif socket==l.from_socket:
 			return (l.to_node, l.to_socket)
 	return (None, None)
+
+def compute_bounding_sphere(points):
+	p1 = max(((p, p.length) for p in points), key=lambda x:x[1])[0]
+	p2 = max(((p, (p-p1).length) for p in points), key=lambda x:x[1])[0]
+	center = (p1+p2)/2
+	radius = (p1-p2).length/2
+	for p in points:
+		d = p-center
+		if d.length>radius:
+			center += d*(1-radius/d.length)/2
+			radius = (radius+d.length)/2
+
+	return center, radius
-- 
2.43.0