How to find where to cast a ray to avoid collision in Bullet?

Question

Say we have an object at point A. It wants to find out if it can move to point B. It has limited velocity so it can only move step by step. It casts a ray at direction it is

Answer 1

I have made this image to tell my idea for reaching the object to point B. Objects in the image :- The dark blue dot represents the object. The red lines are obstacles. The grey dot and line are the area which can be reached. The purple arrow is the direction of the point B. The grey line of the object is the field of visibility. Understanding the image :- The object will have a certain field of visibility. This is a 2d situation so i have assumed the field of visibility to be 180deg. (for human field of visibility refer http://en.wikipedia.org/wiki/Human_eye#Field_of_view ) The object will measure distance by using the idea of SONAR. With the help of SONAR the object can find out the area where it can reach. Using BACKTRACKING, the object can find out the way to the object. If there is no way to go, the object must change its field of visibility