GENERAL OVERVIEW

Croquet is, for the casual user, like a Browser, an application that the general user will open over his desktop. But it is also a tool for the creation of 3D environments that can have usual 2D applications (a commercial application, by example)inside a window inside the 3D environment - we call these applications: "projects". And it is also something like a webserver (Croquet is a peer-to-peer environment).

IMPORTANT DIFFERENCE: Really Croquet IS NOT a web browser because a web browser downloads a page automaticaly when we write its address. The Croquet "browser" will access an "island" - a 3D space having objects, 2D windows, sound, other visitants available for chat etc. - that was downloaded not using the "browser" and not automaticaly in the moment when we do a first contact with the machine having the island . We will learn how to do this download soon.

The appearance of Croquet in the 1.0 version, for the casual user - not a developer - will be not like the actual that you have downloaded and open. Will be only a "viewer" having an empty "island" - like a Browser in the about:blank page.

To open a contact to other visitants of the"island" you need to specify something like the "address+port" of the owner of the island. If you are in a Local Area Network the islands available for contact will appear in a list:

This is valid if the island is "public". If it's private you need to be "invited". Using something like an IM (a Messenger), someone knows that you are online and invites you to visit his island, sending to you an "invite" having something like the "secret" address of it. You can invite other people to visit YOUR island - they need to have, of course, a copy of your island downloaded before.

If you are authorized to access an island (or if it's public) a Portal will appear. A Portal is a 3D window where the avatar can cross. The visitor can execute applications that are in the environment he is with some other visitor (important to remember that a copy of these application was downloaded before, beeing part of the "island download".

If you are inside the other island you can create a Portal to come back to the original island. The Portal you have greate "to go" doesn't exist in that island. Only YOU can use this portal to come back to your world. For the other visitors it will be a mirror.

TIP: An open Portal, if you are "looking" trought it, will use lots of your CPU. So, is a good habit to close it.

NOTE OF THE BETA VERSION: Nothing of this is working 100% OK at this beta version. If you try the samples available, your machine can crash. The menus and pop-windows need to be "cleaned". There are not an easy way to download an island. Etc. Etc.

A Croquet island can have applications or to be something like a website.

Is Croquet only an "academic toy" open source or can be a serious commercial 3D interface?

An "island" is downloaded to the client and the code can be viewed, like we have with web pages having JavaScript code. But remember that a modern network application has three tiers.

We are presenting, in the figure, two professional sceneries: the first uses Java and the other the .NET architecture.

The use of Squeak-Croquet and databases is out of the scope of this course.

An application using Croquet in the first tier can be a mix of "Peer-to-Peer" and " Client-Server" architecture:

IMPORTANT OBSERVATION: We need to make clear a concept. For DMU (we did not invent this), there are 4 levels of Croqueteers:

1 - "Consumers": that know how to use the "navigator" (the "SimpleDemo" included in the download is a navigator for us). They go to available islands in the LAN or internet. They receive visitors for chat.They use 2D "projects" (we will talk about this soon) available at the "hoster islands". They customize their islands adding 3D objects using the graphic resource of the navigator and will use "Brie" - a new Croquet resource that will be available soon.

2 - Authors: do "1" + they know how to create 2D "projects" using the Squeak graphics resourse (not code). They have a "hoster" (the "MPEGDemo" included in the download is a hoster for us) that has his projects added graphicaly to his "hoster island".

3 - Programers: do "1" + "2" + they write code for the projects, using the Smalltalk/Squeak API .

4 - Wizards: do "1" + "2" + "3" + they write code using the Croquet API (for animated, interactive objects, 3D simulations etc. etc). They know Java or .NET and database programming for the creation of the 2nd and 3th tiers, for security and persistence of data on applications using Croquet in the 1st tier.

This tutorials serie is for the level 3 only. We will present a few lessons "using" - copy and paste - the Croquet API but no explanations about the Classes.

We think that the creators of 3D objects (using "3ds max" or any modeler+converter to ASE or MDL file) can be or not Croquet users at any level. But we will have many lessons about how to create 3D objects using Blender at THIS tutorials serie.

May be all of this is a little confuse for you now but will be more clear soon. 


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