Re: [Gzz] 10th & 11th (jvk)

[Tuomas Lukka]

> 
> The current implementation just divides the paper into 
> a 17x17 mesh and modulates the vertex distance from the 
> bulge origin (which should animate better than modulating the
> paper coordinates). 

The bulging looks EXCELLENT. Great work!

> Fisheye parameters: 
>       cs1: paper-to-vertex coordinate mapping
>       cs2: bulge-to-vertex coordinate mapping
>       x0,y0,x1,y1: 
>               the region of the paper (in paper coords) 
>               that is drawn
> 
> Are these ok?

These need to be adjusted a little: when I increase the size of the bulge,
the paper grows too much; the outer coordinate system should define
an approximate bounding box and the whole paper shrunk to better fit
there with the bulge. 

This is because with the buoy view, we need some control on where the
paper actually lies. How about something like "90% of the paper area
will be inside the unit circle (not square) of cs1"?

This is a little more difficult and should maybe be implemented in the Java
side.

Another thing is that it should be EASY to create an interpolation from a bulged
state into a completely non-bulged state: what's the coordinate system when
there's no bulge?

> Possible improvements:
>       - try to find good grid size based on x0,y0,x1,y1
>       - use less vertices where the distortion is close to linear
>       - use projective texture mapping 
>       - implement distortion in vertex programs
>       - use better distortion function
>       - do not evaluate points twice 
>       
> What improvements should be done?

Only the parameter adjustment at first. The next one would be

        - find a reasonable parameter to adjust using Joystick throttle,
          mouse wheel or some other similar 1D controller.

        Tuomas