ovis: add ENTITY_AABB_WORLD property and implement getEntityProperty

Author: paroj

modules/ovis/include/opencv2/ovis.hpp

@@ -45,6 +45,7 @@ enum EntityProperty
 {
     ENTITY_MATERIAL,
     ENTITY_SCALE,
+    ENTITY_AABB_WORLD
 };
 
 /**
@@ -106,6 +107,14 @@ class CV_EXPORTS_W WindowScene {
     /// @overload
     CV_WRAP virtual void setEntityProperty(const String& name, int prop, const String& value) = 0;
 
+    /**
+     * get the property of an entity
+     * @param name entity name
+     * @param prop @ref EntityProperty
+     * @param value the value
+     */
+    CV_WRAP virtual void getEntityProperty(const String& name, int prop, OutputArray value) = 0;
+
     /**
      * convenience method to visualize a camera position
      *

modules/ovis/src/ovis.cpp

@@ -563,6 +563,35 @@ class WindowSceneImpl : public WindowScene
         node.setScale(value[0], value[1], value[2]);
     }
 
+    void getEntityProperty(const String& name, int prop, OutputArray value)
+    {
+        SceneNode& node = _getSceneNode(sceneMgr, name);
+        switch(prop)
+        {
+        case ENTITY_SCALE:
+        {
+            Vector3 s = node.getScale();
+            Mat_<Real>(1, 3, s.ptr()).copyTo(value);
+            return;
+        }
+        case ENTITY_AABB_WORLD:
+        {
+            Entity* ent = dynamic_cast<Entity*>(node.getAttachedObject(name));
+            CV_Assert(ent && "invalid entity");
+            AxisAlignedBox aabb = ent->getWorldBoundingBox(true);
+            Vector3 mn = aabb.getMinimum();
+            Vector3 mx = aabb.getMaximum();
+            Mat_<Real> ret(2, 3);
+            Mat_<Real>(1, 3, mn.ptr()).copyTo(ret.row(0));
+            Mat_<Real>(1, 3, mx.ptr()).copyTo(ret.row(1));
+            ret.copyTo(value);
+            return;
+        }
+        default:
+            CV_Error(Error::StsBadArg, "unsupported property");
+        }
+    }
+
     void _createBackground()
     {
         String name = "_" + sceneMgr->getName() + "_DefaultBackground";