ovis: add Ogre3D based visualizer module

modules/ovis/samples/ovis_demo.py

@@ -0,0 +1,28 @@
+import cv2
+import numpy as np
+
+# add some external resources
+cv2.ovis.addResourceLocation("packs/Sinbad.zip")
+
+# camera intrinsics
+imsize = (800, 600)
+K = np.diag([800, 800, 1])
+K[:2, 2] = (400, 100) # offset pp
+
+# observer scene
+owin = cv2.ovis.createWindow("VR", imsize)
+cv2.ovis.createGridMesh("ground", (10, 10), (10, 10))
+owin.createEntity("ground", "ground", rot=(1.57, 0, 0))
+owin.createCameraEntity("cam", K, imsize, 5)
+owin.createEntity("figure", "Sinbad.mesh", (0, -5, 0))  # externally defined mesh
+owin.createLightEntity("sun", (0, 0, -100))
+
+# interaction scene
+iwin = cv2.ovis.createWindow("AR", imsize, cv2.ovis.SCENE_SEPERATE | cv2.ovis.SCENE_INTERACTIVE)
+iwin.createEntity("figure", "Sinbad.mesh", (0, -5, 0))
+iwin.createLightEntity("sun", (0, 0, -100))
+iwin.setCameraIntrinsics(K, imsize)
+
+while cv2.ovis.renderOneFrame():
+    R, t = iwin.getCameraPose()
+    owin.setEntityPose("cam", t, R)