fixed combine() resulting in incorrect normals because of not conside…

…ring rotation and scale.

ursina/scripts/combine.py

@@ -67,8 +67,13 @@ def combine(combine_parent, analyze=False, auto_destroy=True, ignore=[], ignore_
                 cols.extend((e.color, ) * len(e.model.vertices))
 
             if include_normals:
+                rotation_scale_matrix = vertex_to_world_matrix.getUpper3()  # get the rotation and scaling part of the matrix
+                normal_to_world_matrix = rotation_scale_matrix
+                normal_to_world_matrix.invertInPlace()
+                normal_to_world_matrix.transposeInPlace()
+
                 if e.model.normals: # if has normals
-                    norms.extend(e.model.normals)
+                    norms.extend([Vec3(*normal_to_world_matrix.xform(Vec3(*n)))for n in e.model.normals])
                 else:
                     norms.extend((Vec3.up, ) * len(e.model.vertices))
 
@@ -96,11 +101,12 @@ def combine(combine_parent, analyze=False, auto_destroy=True, ignore=[], ignore_
     from ursina import *
     app = Ursina()
 
-    from ursina.shaders import lit_with_shadows_shader
+    from ursina.shaders import lit_with_shadows_shader, normals_shader
     Entity.default_shader = lit_with_shadows_shader
+    # Entity.default_shader = normals_shader
 
     p = Entity(texture='brick')
-    e1 = Entity(parent=p, model='sphere', y=1.5, color=color.pink)
+    e1 = Entity(parent=p, model='sphere', y=1.5, color=color.pink, rotation_y=90)
     e2 = Entity(parent=p, model='cube', color=color.yellow, x=1, origin_y=-.5, texture='brick')
     e3 = Entity(parent=e2, model='cube', color=color.yellow, y=2, scale=.5, texture='brick', texture_scale=Vec2(3,3), texture_offset=(.1,.1))
     e4 = Entity(parent=p, model='plane', color=color.lime, scale=10, texture='brick', texture_scale=Vec2(5,5))
@@ -110,10 +116,9 @@ def input(key):
             from time import perf_counter
             t = perf_counter()
             p.combine(include_normals=True)
-            # p.model.generate_normals(smooth=False)
             p.shader = lit_with_shadows_shader
+            # p.shader = normals_shader
             p.texture='brick'
-            print(p.model.normals)
             print('combined in:', perf_counter() - t)