Line of Sight
The requirement of an clear view from the agent doing an action to the target of the action.
Many of the actions done in games are done through avatars or units, and these may diegetically not be able to perceived the game state in the same way as the players controlling them. When the avatars and units can only act on things they themselves can perceive this is most often determined if they have a clear Line of Sight to that which they wish to interact with.
Contents
Examples
Most Miniature Games and tactical Wargames, e.g. Warhammer 40K, Advanced Squad Leader, and Memoir '44, require that firing units have clear Line of Sight to their targets. This is in many cases not only dependent on the absence of buildings, rubble, and blocking vegetation but also the ground itself when the battlefield has height differences. Units excepted from having to have Line of Sight include artillery and other units capable of indirect fire, but these may require having other units spotting for them.
In Frag avatars can only shoot at the other avatars which are not hidden behind walls.
Just Cause 2 lets players shoot with grappling hooks at anything they can aim at in order to move there, or draw items and people towards the players' avatars. Several mods to the Quake series include similar grappling hooks to make movement easier. The Legend of Zelda series also contains grappling hooks but only lets players hook onto specific parts of the game world with them. Portal lets players shoot portals to whatever part of a level they can see (except through some types of glass), and can then move there by entering the matching portals.
Using the pattern
A basic requirement for Line of Sight is that there are things can see, typically Agents such as Avatars or Units, so making use of the pattern requires choosing how each of these are affected by it. Typically all makes use of it in some sense but varying how it is applied, e.g. that some Units can ignore some Environmental Effects, is a way of providing Privileged Abilities to these.
Line of Sight is most often used to modulate Combat, but can also be used as a part of Movement (e.g. the use of grappling hooks in Just Cause 2 or the portals in Portal). For Combat, the use of Line of Sight opens up for the possibility of having indirect fire as Privileged Abilities, although they may still require Line of Sight from others. All these examples are also examples of modulating Aim & Shoot, but Line of Sight may also be used to trigger Automated Responses from Traps or waiting Agents and this can be used to create Stealth goals.
Line of Sight requires that there is something that can block it in the Levels or Game Worlds, and this is typically Environmental Effects, Game Items, or simply walls and other Obstacles.
Aim & Shoot instantiates Line of Sight (in addition to Line of Sight being able to modulate Aim & Shootsince being able to aim requires being able to have Line of Sight to what one is shooting at. In contrast, the presence of Line of Sight in a game can be used to create Alignment goals.
Diegetic Aspects
Although Line of Sight does not usually need to be visualized in Game Worlds since it represents seeing rather than something than can be seen, some Traps than make use of Line of Sight can be diegetically motivate, e.g. laser beams or even trip wires.
Consequences
When applied to Units or Avatars under players' control, Line of Sight changes their Focus Loci and thereby how they have to relate to Game Worlds and Levels, and what is in them. Since it requires players to consider spatial relations from specific point of view in the Game Worlds, Line of Sight can encourage Spatial Engrossment.
When Line of Sight is used to create Stealth goals, it leads to Stimulated Planning since players have to consider which Agents or Traps can detect them from all locations that need to be entered.
Relations
Can Instantiate
Alignment, Spatial Engrossment, Stealth
with Stealth
Can Modulate
Agents, Automated Responses, Avatars, Combat, Focus Loci, Game Worlds, Levels, Movement, Traps, Units
Can Be Instantiated By
Can Be Modulated By
Environmental Effects, Game Items, Obstacles, Privileged Abilities
Possible Closure Effects
Potentially Conflicting With
History
New pattern created in this wiki.
References
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Acknowledgements
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