calculate diagonal size of the scene

Author: einarf

demosys/scene/scene.py

@@ -4,7 +4,7 @@
 from .shaders import MeshShader, ColorShader, TextureShader, FallbackShader
 from demosys.opengl import geometry
 from demosys.resources import shaders
-from pyrr import matrix44
+from pyrr import matrix44, vector3
 
 
 class Scene:
@@ -27,6 +27,8 @@ def __init__(self, name, loader=None, mesh_shaders=None, **kwargs):
 
         self.bbox_min = None
         self.bbox_max = None
+        self.diagonal_size = 1.0
+
         self.bbox_vao = geometry.bbox()
         self.bbox_shader = shaders.get('scene_default/bbox.glsl', create=True)
 
@@ -79,6 +81,8 @@ def calc_scene_bbox(self):
         self.bbox_min = bbox_min
         self.bbox_max = bbox_max
 
+        self.diagonal_size = vector3.length(self.bbox_max - self.bbox_min)
+
     def load(self, path):
         """Deferred loading if a loader is specified"""
         if not hasattr(self, 'loader'):