Before revision:  In the constant-memory model, so, we improve time-complexity of previous works such that it just depends on n . Actually, we provide a linear-time , constant-space, strict in-place and 2-pass algorithm for computing visibility area of a point inside a simple polygon , set of non-crossed line-segments and set of non-intersected simple polygons .
After revision:  In the constant-memory model, so, we improve time-complexity of previous works such that it just depends on n . Actually, we provide a linear-time , constant-space, strict in-place and 2-pass algorithm for computing visibility area of a viewpoint inside a simple polygon , set of non-crossed line-segments and set of non-intersected simple polygons .