This asset is now free and no more supported.
Build with and for GMS 1.4. This is a grid based shadow casting. Ideal for roguelikes and grid based games. It uses a ray casting method. It manages unseen cells(black) and already seen cells(semi-transparent). You must be familiar with the ds_grids functions and surfaces. Easy to implement in any other projects. As always, everything is well commented.
Cleaner code and added parentheses to statements and semicolon to all lines.