Ducts, Why Did it Have to be Ducts?

March 8, 2019

Throughout the development of Sleuthhounds: Cruise I’ve been constantly looking to incorporate novel scenarios. The game is fundamentally a traditional point-n-click adventure, but any time I can put a bit of a twist in I’ve been trying to take advantage of that. Back when adventure games were the AAA titles of the 80’s and 90’s, with bigger budgets and more staff, more interesting/different scenarios tended to get incorporated than in more modern adventure games. These older games are great for inspiration, and one such adventure led to the inclusion of a section where Pureluck Homes gets to sneak around the cruise ship in the air vents.

Only the corridors Indy can see are shown in Indiana Jones and the Last Crusade.

LucasArts’s adventure game adaptation of Indiana Jones and the Last Crusade had a number of rough edges to it. But it also did some interesting things that I haven’t really seen in any other adventure games. One of these sections involves Indy’s search of Castle Brunwald, where his father is being held prisoner. In the game, as Indy moves through the halls of the castle the viewpoint shifts from the traditional graphic adventure side on view to an overhead perspective. From this perspective, only those corridors that Indy himself has line of sight on are revealed. When it came time to include a section in Cruise where the player has to maneuver through various ventilation ducts, I thought this would be the perfect effect to pay homage to.

The rough pencil and paper drawing of part of the vents.

With this scene, I started by first whipping up a very rough pencil and paper drawing of the ducts. After scanning this in, I blacked out all the non-duct areas of the image. This created the background for the basic paths that Homes can maneuver through.

Line of sight darkness obscures the vents that Homes can't see.

The next step was to add the line of sight determination. Based on where Homes is standing, the hallways that are visible to him are determined. The non-visible hallways are then mostly covered with black. A bit of the entrance of each hall is revealed to indicate to the player that there is more to the ducts to explore in that direction.

The flashlight limits the view distance in longer sections of the vents.

As a final step, I then added the flashlight effect I previously used in the lounge. This limits how far Homes can see when he’s in some of the longer vents in the ship. The end result is a scene that has something of the claustrophobia that crawling through such ducts would really have.

Obviously the pencil and paper background is very much work in progress. Even if it wasn’t, there are still some details to attend to in the vents. The biggest such detail is the Homes sprite itself. For rough draft development purposes I just used Homes’s standard standing and walking sprites, scaled down to fit the vents. There are two issues with this:

• First, since this sprite is intended to be viewed more side on than top down, the perspective he’s drawn at is at odds with the perspective of the vents so that he doesn’t fit as comfortably into this space as I would like.
• Second, as Homes’s normal sprite scales down the speed at which he moves across the screen also scales down so that it takes longer than I’d like for him to traverse the vents.

The ultimate solution for both these issues will be to create a new homes sprite set for use in the vents. In addition to drawing Homes top-down to look like he’s crawling through the vents, a new sprite set will also allow for his movement rate to be adjusted so that he can crawl through the vents faster than is currently done. Taken together with the line of sight shading and the flashlight effect, it should make for a nice little “flavour” scene in the overall game.

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