Difference between revisions of "Field of Vision"

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* Light whole room. This is the approach used by the original [[Rogue]]. You just make the whole room in which the player character is visible, and all other parts of map not visible. When the character is in a corridor, it can only see one square from where he stands, this doesn't require any sophisticated calculations.
* Light whole room. This is the approach used by the original [[Rogue]]. You just make the whole room in which the player character is visible, and all other parts of map not visible. When the character is in a corridor, it can only see one square from where he stands, this doesn't require any sophisticated calculations.
* [[Extremely fast simplified LOS]] -- Take advantage of the way most roguelike maps are drawn (square rooms connected with corridors).
* [[Extremely fast simplified LOS]] -- Take advantage of the way most roguelike maps are drawn (square rooms connected with corridors).
* [[FastFOV]] -- precalculated approximate FOV using a bitwise AND.
* [[Ray casting]]
* [[Ray casting]]
* [[Shadow casting]]
* [[Shadow casting]]

Revision as of 01:34, 10 November 2009

Some of the most important features on roguelikes, including the presentation of the area that surrounds the player character, require to check the visibility of an object from a given point on the map. For example, it may be necessary to know which parts of map are visible from the place the player character is standing to draw those parts of map on the screen.

There are basically two ways to achieve this; by using Line of Sight to check all the map squares in range, which is a slow method as it repeats most of the calculations multiple times, or by calculating the Field of Vision as a whole.

Approaches

Some of the most common approaches to field of vision are:

Refinements

There are other refinements that can be applied to any approach:

Studies

Available Libraries

  • libfov is a C++ library made by Blue Puyo, which supports both circular FoV and Beams using Shadow casting
  • permissive-fov is a library for both C and C++ written by Jonathon Duerig. It uses Permissive Field of View, and supports arbitrary shaping of FoV using visitation masks. It does not support Beams.
  • libtcod is a C/C++/python library which, while not dedicated to fov, contains implementations of basic raycasting, los_rays (a.k.a. diamond raycasting), recursive shadowcasting and precise permissive fov.