[FreePV-dev] Class structure

[Thomas R. <th...@pa...>]

Hello everybody,

as I said, I would like to work more the "Extreme Programming" way,
not in a "Waterfall" model, so I would like to start with some
design work. We all know that what we want to do, can be done (look at
Quicktime!) so the open question for the plugins are just
implementation details.

What I want to start with is a discussion of the basic object model.
If this is clear, I would suggest we can start implementing a
standalone viewer prototype (because it's much easier to debug) and
implant this code into the different platform specific plugins.

In my opinion, the rough class structure should look like this:

* panorama

abstract base class, platform independent

These objects should hold all
the image data and viewing parameters of one panoramic image (node)
for example [min,max,default] X [pan,tilt,fov]
HDR, Hotspots,...

Subclasses: 

-- cubic
6 cubefaces like QTVR

-- cylindrical
One image in cylindrical projection

-- equirectlinear
One image in equirectlinear projection
....


* controller

Platform independent class to manage user interaction, like
turn, tilt, ... goto next node,...
contains [current] X [pan,tilt,fov]

listens to browser events
provide events

* Render
abstract baseclass. Platform dependent.
Displays the image on the screen

Subclasses: 
-- Legacy
simple draw pixel method

-- Direct2D
draw pixel method for older Computers/to less VRAM

-- DirectX
Win32

-- OpenGLBase
Win32, Linux, MacOS,....

-- OpenGLEx
Use Hardware accelerated HDR display 

....

* loader
abstract baseclass, platform independent

Decodes input files to panorama objects

Subclasses: 
-- Quicktime VR

-- PTViewer

-- SPi-V

.....


All these classes are packed into a small platform dependent
plugin/stand alone player, which handles the low level input/output
and distributes it to the classes, and listens to events of the
controller/render class.

The code structure/sharing will be more complex, because some things
can be shared for the platform (Win32: activeX/Netscape/Standalone,
...) and some things for the browser (netscape: Win32/MacOS/Linux,...)
but for this I would need to know more about all this things.

But I think these layers are very small, so we can start with some
prototypes for each platform, and than look, whats simmilar/reuseable.

What do you think about these ideas?

MfG, 
     Thomas.