WebGL Aquarium Notes

# The WebGL Aquarium

## Controls

- Use the mouse to change various settings.
- Click the * to bring up more settings.
- Press SPACE to change the view.
- Press L for sharks with frikken lasers. Looks best from an outside view.

## Running across multiple machines

The Aquarium demo can by run synchronized across multiple machines.

To run it across multiple machines each machine must be running a browser that supports WebGL and WebSockets. Chromium for example. Next, the clocks of the 5 machines must be in sync. Then start the server. See here for instructions. Finally run the Aquarium with a URL in the following format.

    http://address_of_server:port_of_server/aquarium/aquarium.html?settings={net:{sync:true,rotYMult:mult}}

Where address_of_server is the domain name or ip address of the server, port_of_server is the port of the server, and mult is 0 for the center machine, positive for machines to the right of the server and negative for machines to the left.

In other words, if the server is "myserver.com" and your running on port 8080 and you had 5 machines, A, B, C, D, E in that order left to right and you wanted machine C to be the master the URLs would for each machine would be:

    Machine A: http://myserver.com:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:false,slave:true,fovMult:1.0,rotYMult:-2}}
    Machine B: http://myserver.com:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:false,slave:true,fovMult:1.0,rotYMult:-1}}
    Machine C: http://myserver.com:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:true,slave:false,fovMult:1.0,rotYMult:0}}
    Machine D: http://myserver.com:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:false,slave:true,fovMult:1.0,rotYMult:-1}}
    Machine E: http://myserver.com:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:false,slave:true,fovMult:1.0,rotYMult:-2}}

At that point, settings changed on the master should be propagated to the slaves.

### Options:

ui: | boolean | Whether or not to display a user interface.
sync: | boolean | Whether or not to get settings from a server
slave: | boolean | Whether or not to send settings to the server. False = send
rotYMult: | number | The amount to multiply the field of view for each monitor. Assumes they are all the same size.
fovMult: | number | The amount to multiply the field of view offset for each monitor. The system computes the field of view for the monitor and multiplies by both rotYMult and fovMult to compute how much to rotate the view for each monitor. Think of rotYMult as a per machine setting and fovMult as a global setting. Adjust fovMult to specify the gap between monitors. For example on the Liquid Galaxy in the video above the fovMult is 1.12
fovFudge: | number | The amount to multiply the global field of view all monitors. This is to work around a large array of monitors as the field of view setting is currently for a single monitor. For example if you have 4 monitors across you probably want to set this to 0.25
offset: | array | The amount to offset the frustum. Used to make a large virtual monitor. Example: offset:[-1,0] would define a monitor 1 unit left of the center monitor.
offsetMult: | number | Amount to multiply the offset by. Think of offset as a per machine setting and offsetMult as a global setting.

### Terse Setup

These steps worked for me as of 2011/10/13

On Windows 7

1. download the source
2. download node.js binary for windows from http://nodejs.org/#download
   Mine was 0.5.9
3. cd to the root folder of the samples (ie, "cd webglsamples")
4. open a command prompt and type <path_to_node.js>/node.exe server\server.js
   On my system it was
   f:\Users\gman\Downloads\node.exe server\server.js
   You'll probably get firefall warning from windows. Allow it.
5. Start Chrome 14 or newer
   Note: it doesn't have to be Chrome 14 but it does have to be a browser that supports WebSockets draft-8, 9 or 10
6. Make the window horizontally about 1/2 the size of your monitor or less
7. Make a new tab. Pull it off the window so you now have 2 chrome windows and arrange the 2 windows (which would both be the same size now) side by side
8. In the right window use this URL
   http://localhost:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:true,slave:false,fovMult:1.0,rotYMult:0}}
9. In the left window use this URL
   http://localhost:8080/aquarium/aquarium.html?settings={net:{sync:true,ui:false,slave:true,fovMult:1.0,rotYMult:-1}}

It will take up a few seconds for them to sync I think but it was working for me ;-)

To run it across machines, change "localhost" to the ip address of the machine running node.js

Note: you might have to stop and start node.js which you can do by pressing Ctrl+Break twice in it's window

## Implemenation Notes:

The aquarium runs almost entirely based on a clock. That means the position of the camera and every fish will be the same across machines if their clocks are in sync. When in networked mode each machine keeps its clock in sync by periodically asking the server for the current time. Otherwise, using node.js and the websocket library the master sends a JSON string with any new settings to the server. The server then broadcasts those settings to each of the machines.