What is the Line of Sight (LoS)?
In many strategy games, there is a ’Fog of War (FoW)’ mechanic that defines the area visible to the player. FoW is implemented in different ways. The most common is a ‘visible radius’. Outside of this radius, you have no vision. This method is simplistic and does not simulate how hills, trees and other terrain can obstruct your view.
In Ultimate General: Gettysburg, we use a much more accurate FoW system that simulates actual Line of sight. Simply, units can spot only what they can directly see. For example, they cannot see what is behind a hill unless they climb the hill.
Red area shows what the unit can see. You can enable this "Individual LoS" for your units any time you want, which is especially useful for your artillery to understand its actual effective range.
Another example of how LoS works in Ultimate General: Gettysburg. If you want to see the LoS of a selected unit, you just use a keyboard shortcut, long mouse button press or finger gesture, depending on platform and its LoS is displayed in red for a short time, fading out gradually.
In practice
The map of Ultimate General: Gettysburg features accurate topographical information of the historical battlefield. Every hill, ridge, house and boulder will impact visibility in the game. Units have their spotting ranges adjusted according to their role, with generals, cavalry and artillery having higher view ranges than infantry. As you position them at strategic locations, your army’s visibility increases, while the units use their individual LoS to target local threats. Therefore, it is very important to secure multiple elevated positions to see further and cover more areas with your artillery firepower.
You must place artillery to strategic positions that provide continuous line of fire. In this image, the artillery unit "Hall" is protected by nearby houses from enemy cannon fire while it can shoot directly in front for a decent range.
"Cooper" however cannot participate actively in battle because he is located in flat ground and blocked by many trees and houses.
Tactics based on LoS
When the Confederates arrive at the battlefield with a lack of cavalry and many ridges ahead, they cannot see very far (as is true historically). On the contrary, the Union army controls the hills and has better visibility over the map with their Videttes searching for enemy movements. Cavalry is more mobile, so it can remain at the edges of the enemy’s forces, providing information for your army.
Another useful tactic is to place artillery batteries on ridges and hills to gain a wider view of the battlefield and be able to bombard the enemy from a distance. Losing the high ground can result in a decreased visibility of the battleground and reduced artillery effectiveness, as most of your cannons will not be able to aim directly at enemy forces.
LoS also gives you the ability to conceal your reserves behind hills, forested areas and houses. For instance, you can conceal part of your forces behind a ridge like Cemetery Ridge while fighting takes place on the other side. At the right moment, you can bring your fresh reserves to support your lines. You can even ambush your opponent because the LoS impacts the AI in the same way as you, so AI forces will not know exactly where your hidden forces are.
Hood's Division approaching Round Top, not able to see too much ahead because of the high ground and forested areas that obstruct the view.
Gradually from the fog of war appear AI Union sharpshooters that attempt to delay the advance of Hood's division. The battle of Devil's Den has just begun!
AI and LoS
As we have explained in our previous developer blog, our AI does not use any cheats or statistical bonuses, so it was extra challenging to make the AI respond properly when it has limited visibility. Despite the difficulties, we have successfully simulated the tactical evaluation of invisible areas. The AI will dispatch forces to unknown ground before player forces become visible in anticipation of the enemy. The most skilled AI personalities are able to execute these ’blind maneuvers’ more effectively, re-creating a real General’s expectations or instincts about the whereabouts of the enemy and the importance of strategic locations.
The Confederate army (Player) not able to find the exact Union's army whereabouts on Cemetery hill because of the many ridges that block visibility.
We see now the visibility of the Union army as player in the same battle.
LoS graphical appearance
As seen in the images, non-visible areas are covered by the FoW. It is vital to note that when enemy units become visible, they do not ’pop-up’ as in most strategy games, but are gradually revealed . As the enemy progressively comes into vision, its flag is slowly shown, so you see its size and name. When the enemy starts to leave LoS, we see the opposite fade out effect.
Confederate troops appearing gradually from fog of war.
If you want to see the LoS of a selected unit, you just use a keyboard shortcut, long mouse button press or finger gesture, depending on platform and its LoS is displayed in red for a short time, fading out gradually.
Union Videttes reveal concealed Confederate forces.
Additional information will follow soon with more videos. Good luck out there, generals!
Notes from the author:
- The article was first published in our official blog Ultimategeneral.com on 11/2/2014
- Ultimate General: Gettysburg has been greenlit by Steam on 19/2/2014 and will soon be available in Early Access version.
