View port vs. view plane camera (was Re: Quesa - "Most Wanted" list)

[Edward K. C. <ek...@lg...>]

On Jun 2, 2004, at 22:44, James W. Walker wrote:

> On Jun 2, 2004, at 7:42 AM, Edward K. Chew wrote:
>
>> 6. View plane camera?
>>
>> Hey, I thought I'd toss that one out FWIW, as it is the last 
>> remaining unimplemented feature which continues to break my app.  
>> Then again, maybe I'm the only one who ever used it.  :-)
>>
>> Mostly, it came in handy for generating high-res and occasionally 
>> multipage printouts, but I have had to disable that feature under 
>> Quesa.  It's also nice at times to be able to pan around a scene 
>> without having the perspective shift.
>
> It's possible to do much the same things (maybe not as easily) using 
> Q3DrawContext_SetPane, Q3DrawContext_SetPaneState, and 
> Q3Camera_SetViewPort.  Quesa's documentation on TQ3CameraViewPort even 
> suggests that it can be used to divide an image into strips for 
> printing.

Interesting!  I never thought of using the view port that way, but I 
guess it ought to work.  So let's say I want to get my "hand" tool 
working the way it once did.  Right now, I am moving the point of 
interest laterally, but this makes it look like I'm flying over the 
view below rather than moving around a large, static snapshot of it.

Since you are confined within the 2 x 2 view port dimensions, I guess 
the only way to move away from the point of interest would be to shrink 
down the view port and offset it from (0,0).  The further away from the 
point of interest the user goes, the more you would have to shrink it.  
At the same time, you would need to move the camera further out (and 
adjust hither and yon accordingly) to make up for having an 
ever-smaller portion of the view being rendered in the same-sized 
window pane.  Am I on the right track?

-Ted