CS 404/504 Games and Virtual Environments Homework #4

This first virtual environments assignment includes two tasks that may be done in parallel.

1. SecondLife

Read about LindenScript and how to create virtual objects in SL. Suppose we want to create a virtual chair that approximates a real chair, how do we do it?

2. Build a Very-Small-Scale CVE-compatible Model

Code-wise, you are to download and use the jeb1, jeb2, or jeb3 demos, probably start with jeb1.

Functionalitywise, you are to select and depict one of the following Treasure Island locations

Admiral Benbow Inn

The tavern where the story starts. You could go model a real local tavern, or design one from scratch. In Phase 1, you are looking for the basic room structure, the textures for the floor, walls, and ceiling, and "decorations": art objects such as (textures of) windows, fireplaces, carpets, etc.

The good ship Hispaniola

With a basic layout allowing key plot points to occur, Probably there is at least a "deck" and a "hold" with access between them.

The treasure island

The island in the book was fairly large. We probably need at least a beach, a hut, and a cave, if I recall correctly.

1. model your location; establish its basic position and dimensions
2. (for inn and ship) identify adjacencies and connect rooms and make them reachable from the rest of the model via door(s) or opening(s).
3. collect textures for your location. Class Rule: you may not use textures for which you do not have legal rights. Write games about pirates, but do not pirate anything yourself.
4. add virtual tables, chairs, plants, etc. as needed in your room. You will need to put your room into CVE's dat/uidaho model format in your local/standalone client (jeb1, jeb2, jeb3, or cve).

Some Guidelines

1. This assignment is largely inventing (or measuring), gathering and collecting data. Doing a good job may be difficult.
2. A rectangular area's basic dimensions are x,y,z,l,h,w where x2=x+l (l is length), y2=y+h (h is height), and z2=z+w (w is width). Please use units of meters. Given a floor plan or other 2D top-down birdseye view sketch, you can use the FHN program to get your x,z and the x2,z2 from which l and w are computed by subtraction.
3. . "y": you will have to decide how high the ceilings are, and how much space between floors.
4. You will need a lot of textures. One way to get them is to take a lot of digital camera photos. You can also find textures on the internet.
5. Digital camera images require image editing work before they are usable in a virtual environment. MS Paint is OK for low-end stuff; so is a X11 tool called "xv" if you can still find it. The Gimp turns out to be a quite splendid free image editor; Adobe Photoshop is a market leader among commercial tools. Photos that will eventually be used as textures need to (a) focus on a particular surface, (b) be taken "straight on", not at an angle, (c) minimize glare due to lighting, and (d) shoot at lower resolutions. Eventually all textures will have to be edited into nice clean small images whose length and width are powers of two. For this assignment we are not going to be picky (yet).

Example Room Model

North is upside down in this picture, which was drawn from the point of view of sitting in Jeffery's office chair.

Besides knowing which axes are which (i.e. that north is upside down), unless the room is the only location in the whole program, a localized room model like this would usually need world coordinates that determine its position in the world. You could skip this in a HW4 that wasn't tying all the locations together.

For the JEB example, the FHN program, applied to the JEB floor plan bounding points of JEB 230, gives (x,z) coordinates of (26.6, 11.3). Does this make sense? I guess so; due to the building's L shape, JEB 230's north-facing window does not imply a z value of 0. For a y value, Jeffery goes with 40.5 feet (13.5 feet per floor for Ground, 1st, up to 2nd) = 12.3 meters up. The room's height of 11.5 feet is = 3.5 meters.

Jeffery decides there are really 3 rectangular "Room" objects to model in order to reach the main corridor: the jeb230 (large almost-square), jeb228 (thinner, former secretary area, nearer the main corridor), and the mini-corridor the two doors open out into. It is probably useful to start with the first one, and then add rooms piece-by-piece.

Room {
name JEB230
x 26.6
y 12.3
z 11.3
w 3.15
h 3.5
l 3.93
}

Jeffery gets a $10 camera and snaps a few images from which he hopes to make textures. The resolution is incredibly low, but for videogame decoration purposes, the resolution cannot go very high anyhow.

From these he uses an image editor to cut out the parts least tainted by lighting irregularity, scales to dimensions that are powers of 2, and produces the following textures.

With textures like these, Jeffery can now fill in his room details (wall texture, floor texture, and wall decorations):

Room {
name JEB230
x 26.6
y 12.3
z 11.3
w 3.15
h 3.5
l 3.93
texture jeb230wall.gif
floor Wall {
texture jeb230carpet.gif
}
decorations [
   Wall { texture jeb230art.gif
          coords [29.7,13.3,13.3,
		  29.7,13.8,13.3,
		  29.7,13.8,13.6,
		  29.7,13.3,13.6]
      }
   Wall { texture jeb230calendar.gif
          coords [26.65,13.3,13.3,
		  26.65,13.8,13.3,
		  26.65,13.8,13.6,
		  26.65,13.3,13.6]
      }
]
}

Repeating this for his other rooms, the main remaining detail will be to add Doors or Openings. Here are a couple examples.

Opening{
x 26.6
y 12.3
z 15.23
w 2.2
height 3.5
collide_in 1.2
plane 3
rooms [JEB228, JEB230]
}

Door {
x 28.9
y 12.3
z 15.23
w 0.8
height 2.2
collide_in 1.2
plane 3
rooms [JEB230 , corridor 230]
}

Engine Design Comments

• Notice that the class Room is used in the model.dat format for rectangular spaces that may be part of a larger logical room, or a space that isn't really a room at all.
• Notice that the class Wall is used for all 2D surfaces rendered using DrawPolygon, not just walls. Under OpenGL at least, all vertices have to lie on a plane.
• I have strong reservations about how the current model.dat file format uses absolute coordinates in subobjects such as the decorations. It would probably better to use room-relative coordinates.
• The syntax would benefit from being further nested -- it makes good sense to go even further than the previous bullet and allow the attachment of decorations to specific subcomponents of the room, such as the wall that a poster is mounted on, so that if the wall were moved (if interactive model editing were allowed), the attached decorations would move automatically.
• Notice that the walls of the room object are implicit, which makes attaching decorations to them in the file format difficult, unless the rules for attaching decorations were also implicit...