Panda3d Robotics
I would suggest you to go for ROS(gazebo) and write your nodes in C++ or python. You can follow Lentin Joseph's book on Learning Robotics Using Python. It helps you in building autonomous bots with ROS and OpenCV.
The title makes it obvious, is this a good idea? I've been looking for a robotics simulator in languages i know (i know ruby best, then c++, then python -- want to strengthen here--, forget about javascript, but i know it). 

i found something called pyro, but it probably doesn't fit my needs (listed below). 

In my last university term i learned c++, then they took me to RobotC (which was only about 2 months of the term). Pyro seems similar but now i want something different.

I need something that allows to import graphics, allows 3d environments, allows to easily modify actions robot can perform. Also provides other things necessary for robot programming, like a sensor.